Refactor sr-api to not depend on client anymore (#4086)

* Refactor sr-api to not depend on client anymore * Fix benches * Apply suggestions from code review Co-Authored-By: Tomasz Drwięga <tomusdrw@users.noreply.github.com> * Apply suggestions from code review
2026-05-07 21:18:01 +00:00 · 2019-11-11 16:26:49 +01:00
parent e26d1a0b3e
commit 2ecffa1cd0
140 changed files with 1514 additions and 984 deletions
@@ -125,7 +125,7 @@ version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -785,7 +785,7 @@ version = "0.1.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -1074,7 +1074,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
 "synstructure 0.12.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

@@ -1308,7 +1308,7 @@ dependencies = [
 "proc-macro-hack 0.5.10 (registry+https://github.com/rust-lang/crates.io-index)",
 "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -1746,7 +1746,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -1855,7 +1855,7 @@ dependencies = [
 "proc-macro-crate 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
 "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -2806,6 +2806,7 @@ dependencies = [
 "rustc-hex 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "safe-mix 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "serde 1.0.102 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-api 2.0.0",
 "sr-io 2.0.0",
 "sr-primitives 2.0.0",
 "sr-staking-primitives 2.0.0",
@@ -2840,12 +2841,14 @@ dependencies = [
 "srml-transaction-payment-rpc-runtime-api 2.0.0",
 "srml-treasury 2.0.0",
 "srml-utility 2.0.0",
- "substrate-client 2.0.0",
+ "substrate-block-builder-runtime-api 2.0.0",
 "substrate-consensus-babe-primitives 2.0.0",
+ "substrate-inherents 2.0.0",
 "substrate-keyring 2.0.0",
 "substrate-offchain-primitives 2.0.0",
 "substrate-primitives 2.0.0",
 "substrate-session 2.0.0",
+ "substrate-transaction-pool-runtime-api 2.0.0",
 "substrate-wasm-builder-runner 1.0.4",
 ]

@@ -2889,6 +2892,7 @@ dependencies = [
 "parity-scale-codec 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "safe-mix 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "serde 1.0.102 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-api 2.0.0",
 "sr-io 2.0.0",
 "sr-primitives 2.0.0",
 "sr-std 2.0.0",
@@ -2904,11 +2908,13 @@ dependencies = [
 "srml-system 2.0.0",
 "srml-timestamp 2.0.0",
 "srml-transaction-payment 2.0.0",
- "substrate-client 2.0.0",
+ "substrate-block-builder-runtime-api 2.0.0",
 "substrate-consensus-aura-primitives 2.0.0",
+ "substrate-inherents 2.0.0",
 "substrate-offchain-primitives 2.0.0",
 "substrate-primitives 2.0.0",
 "substrate-session 2.0.0",
+ "substrate-transaction-pool-runtime-api 2.0.0",
 "substrate-wasm-builder-runner 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

@@ -3274,7 +3280,7 @@ dependencies = [
 "proc-macro-hack 0.5.10 (registry+https://github.com/rust-lang/crates.io-index)",
 "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -3372,7 +3378,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -3382,7 +3388,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -3901,7 +3907,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -4064,7 +4070,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -4228,24 +4234,47 @@ version = "0.5.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"

 [[package]]
-name = "sr-api-macros"
+name = "sr-api"
 version = "2.0.0"
 dependencies = [
- "blake2-rfc 0.2.18 (registry+https://github.com/rust-lang/crates.io-index)",
 "criterion 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "parity-scale-codec 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "proc-macro-crate 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustversion 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-api-proc-macro 2.0.0",
 "sr-primitives 2.0.0",
+ "sr-std 2.0.0",
 "sr-version 2.0.0",
- "substrate-client 2.0.0",
- "substrate-consensus-common 2.0.0",
 "substrate-primitives 2.0.0",
 "substrate-state-machine 2.0.0",
 "substrate-test-runtime-client 2.0.0",
- "syn 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "sr-api-proc-macro"
+version = "2.0.0"
+dependencies = [
+ "blake2-rfc 0.2.18 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro-crate 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-api 2.0.0",
+ "sr-primitives 2.0.0",
+ "sr-version 2.0.0",
+ "substrate-test-runtime-client 2.0.0",
+ "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "sr-api-test"
+version = "2.0.0"
+dependencies = [
+ "parity-scale-codec 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustversion 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-api 2.0.0",
+ "sr-primitives 2.0.0",
+ "sr-version 2.0.0",
+ "substrate-consensus-common 2.0.0",
+ "substrate-state-machine 2.0.0",
+ "substrate-test-runtime-client 2.0.0",
 "trybuild 1.0.17 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

@@ -4296,6 +4325,7 @@ dependencies = [
 "sr-io 2.0.0",
 "sr-std 2.0.0",
 "substrate-application-crypto 2.0.0",
+ "substrate-inherents 2.0.0",
 "substrate-offchain 2.0.0",
 "substrate-primitives 2.0.0",
 ]
@@ -4510,9 +4540,9 @@ version = "2.0.0"
 dependencies = [
 "parity-scale-codec 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "serde 1.0.102 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-api 2.0.0",
 "sr-primitives 2.0.0",
 "sr-std 2.0.0",
- "substrate-client 2.0.0",
 ]

 [[package]]
@@ -4838,7 +4868,7 @@ dependencies = [
 "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "sr-primitives 2.0.0",
- "syn 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -4884,9 +4914,8 @@ version = "2.0.0"
 dependencies = [
 "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "sr-api-macros 2.0.0",
 "srml-support-procedural-tools 2.0.0",
- "syn 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -4897,7 +4926,7 @@ dependencies = [
 "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "srml-support-procedural-tools-derive 2.0.0",
- "syn 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -4906,7 +4935,7 @@ version = "2.0.0"
 dependencies = [
 "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -4983,7 +5012,7 @@ name = "srml-system-rpc-runtime-api"
 version = "2.0.0"
 dependencies = [
 "parity-scale-codec 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "substrate-client 2.0.0",
+ "sr-api 2.0.0",
 ]

 [[package]]
@@ -5039,9 +5068,9 @@ version = "2.0.0"
 dependencies = [
 "parity-scale-codec 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "serde 1.0.102 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-api 2.0.0",
 "sr-primitives 2.0.0",
 "sr-std 2.0.0",
- "substrate-client 2.0.0",
 ]

 [[package]]
@@ -5136,7 +5165,7 @@ dependencies = [
 "proc-macro-error 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -5204,6 +5233,7 @@ dependencies = [
 "prost 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "prost-build 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "serde_json 1.0.41 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-api 2.0.0",
 "sr-primitives 2.0.0",
 "substrate-authority-discovery-primitives 2.0.0",
 "substrate-client 2.0.0",
@@ -5218,9 +5248,9 @@ name = "substrate-authority-discovery-primitives"
 version = "2.0.0"
 dependencies = [
 "parity-scale-codec 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-api 2.0.0",
 "sr-primitives 2.0.0",
 "sr-std 2.0.0",
- "substrate-client 2.0.0",
 ]

 [[package]]
@@ -5231,6 +5261,7 @@ dependencies = [
 "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
 "parity-scale-codec 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "sr-primitives 2.0.0",
+ "substrate-block-builder 2.0.0",
 "substrate-client 2.0.0",
 "substrate-consensus-common 2.0.0",
 "substrate-inherents 2.0.0",
@@ -5251,6 +5282,28 @@ dependencies = [
 "sha2 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

+[[package]]
+name = "substrate-block-builder"
+version = "2.0.0"
+dependencies = [
+ "parity-scale-codec 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-api 2.0.0",
+ "sr-primitives 2.0.0",
+ "substrate-block-builder-runtime-api 2.0.0",
+ "substrate-primitives 2.0.0",
+ "substrate-state-machine 2.0.0",
+]
+
+[[package]]
+name = "substrate-block-builder-runtime-api"
+version = "2.0.0"
+dependencies = [
+ "sr-api 2.0.0",
+ "sr-primitives 2.0.0",
+ "sr-std 2.0.0",
+ "substrate-inherents 2.0.0",
+]
+
 [[package]]
 name = "substrate-build-script-utils"
 version = "2.0.0"
@@ -5276,7 +5329,7 @@ dependencies = [
 "proc-macro-crate 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
 "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -5331,10 +5384,11 @@ dependencies = [
 "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
 "parity-scale-codec 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "sr-api-macros 2.0.0",
+ "sr-api 2.0.0",
 "sr-primitives 2.0.0",
 "sr-std 2.0.0",
 "sr-version 2.0.0",
+ "substrate-block-builder 2.0.0",
 "substrate-client-db 2.0.0",
 "substrate-consensus-common 2.0.0",
 "substrate-executor 2.0.0",
@@ -5388,12 +5442,14 @@ dependencies = [
 "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
 "parity-scale-codec 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-api 2.0.0",
 "sr-io 2.0.0",
 "sr-primitives 2.0.0",
 "sr-version 2.0.0",
 "srml-aura 2.0.0",
 "srml-support 2.0.0",
 "substrate-application-crypto 2.0.0",
+ "substrate-block-builder-runtime-api 2.0.0",
 "substrate-client 2.0.0",
 "substrate-consensus-aura-primitives 2.0.0",
 "substrate-consensus-common 2.0.0",
@@ -5416,10 +5472,10 @@ name = "substrate-consensus-aura-primitives"
 version = "2.0.0"
 dependencies = [
 "parity-scale-codec 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-api 2.0.0",
 "sr-primitives 2.0.0",
 "sr-std 2.0.0",
 "substrate-application-crypto 2.0.0",
- "substrate-client 2.0.0",
 ]

 [[package]]
@@ -5442,12 +5498,15 @@ dependencies = [
 "pdqselect 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "rand 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "schnorrkel 0.8.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-api 2.0.0",
 "sr-io 2.0.0",
 "sr-primitives 2.0.0",
 "sr-version 2.0.0",
 "srml-babe 2.0.0",
 "srml-support 2.0.0",
 "substrate-application-crypto 2.0.0",
+ "substrate-block-builder 2.0.0",
+ "substrate-block-builder-runtime-api 2.0.0",
 "substrate-client 2.0.0",
 "substrate-consensus-babe-primitives 2.0.0",
 "substrate-consensus-common 2.0.0",
@@ -5473,10 +5532,10 @@ version = "2.0.0"
 dependencies = [
 "parity-scale-codec 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "schnorrkel 0.8.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-api 2.0.0",
 "sr-primitives 2.0.0",
 "sr-std 2.0.0",
 "substrate-application-crypto 2.0.0",
- "substrate-client 2.0.0",
 "substrate-consensus-slots 2.0.0",
 ]

@@ -5509,6 +5568,7 @@ dependencies = [
 "parity-scale-codec 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "sr-primitives 2.0.0",
 "srml-timestamp 2.0.0",
+ "substrate-block-builder-runtime-api 2.0.0",
 "substrate-client 2.0.0",
 "substrate-consensus-common 2.0.0",
 "substrate-consensus-pow-primitives 2.0.0",
@@ -5521,9 +5581,9 @@ name = "substrate-consensus-pow-primitives"
 version = "2.0.0"
 dependencies = [
 "parity-scale-codec 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-api 2.0.0",
 "sr-primitives 2.0.0",
 "sr-std 2.0.0",
- "substrate-client 2.0.0",
 "substrate-primitives 2.0.0",
 ]

@@ -5588,7 +5648,7 @@ version = "2.0.0"
 dependencies = [
 "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -5655,6 +5715,7 @@ dependencies = [
 "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "rand 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "serde_json 1.0.41 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-api 2.0.0",
 "sr-primitives 2.0.0",
 "srml-finality-tracker 2.0.0",
 "substrate-client 2.0.0",
@@ -5682,10 +5743,10 @@ version = "2.0.0"
 dependencies = [
 "parity-scale-codec 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "serde 1.0.102 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-api 2.0.0",
 "sr-primitives 2.0.0",
 "sr-std 2.0.0",
 "substrate-application-crypto 2.0.0",
- "substrate-client 2.0.0",
 ]

 [[package]]
@@ -5701,10 +5762,11 @@ dependencies = [
 name = "substrate-inherents"
 version = "2.0.0"
 dependencies = [
+ "derive_more 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "parity-scale-codec 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "sr-primitives 2.0.0",
 "sr-std 2.0.0",
+ "substrate-primitives 2.0.0",
 ]

 [[package]]
@@ -5764,6 +5826,7 @@ dependencies = [
 "slog_derive 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "smallvec 0.6.10 (registry+https://github.com/rust-lang/crates.io-index)",
 "sr-primitives 2.0.0",
+ "substrate-block-builder 2.0.0",
 "substrate-client 2.0.0",
 "substrate-consensus-babe-primitives 2.0.0",
 "substrate-consensus-common 2.0.0",
@@ -5799,6 +5862,7 @@ dependencies = [
 "parity-scale-codec 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "rand 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-api 2.0.0",
 "sr-primitives 2.0.0",
 "substrate-client 2.0.0",
 "substrate-client-db 2.0.0",
@@ -5816,8 +5880,8 @@ dependencies = [
 name = "substrate-offchain-primitives"
 version = "2.0.0"
 dependencies = [
+ "sr-api 2.0.0",
 "sr-primitives 2.0.0",
- "substrate-client 2.0.0",
 ]

 [[package]]
@@ -5920,6 +5984,7 @@ dependencies = [
 "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "rustc-hex 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "serde_json 1.0.41 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-api 2.0.0",
 "sr-io 2.0.0",
 "sr-primitives 2.0.0",
 "sr-version 2.0.0",
@@ -6011,7 +6076,7 @@ dependencies = [
 "rustversion 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "substrate-externalities 2.0.0",
 "substrate-runtime-interface 2.0.0",
- "syn 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
 "trybuild 1.0.17 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

@@ -6065,6 +6130,7 @@ dependencies = [
 "serde 1.0.102 (registry+https://github.com/rust-lang/crates.io-index)",
 "serde_json 1.0.41 (registry+https://github.com/rust-lang/crates.io-index)",
 "slog 2.5.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-api 2.0.0",
 "sr-io 2.0.0",
 "sr-primitives 2.0.0",
 "substrate-application-crypto 2.0.0",
@@ -6086,6 +6152,7 @@ dependencies = [
 "substrate-telemetry 2.0.0",
 "substrate-test-runtime-client 2.0.0",
 "substrate-transaction-pool 2.0.0",
+ "substrate-transaction-pool-runtime-api 2.0.0",
 "sysinfo 0.9.5 (registry+https://github.com/rust-lang/crates.io-index)",
 "target_info 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "tokio 0.1.22 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -6116,10 +6183,9 @@ dependencies = [
 name = "substrate-session"
 version = "2.0.0"
 dependencies = [
+ "sr-api 2.0.0",
 "sr-primitives 2.0.0",
 "sr-std 2.0.0",
- "substrate-client 2.0.0",
- "substrate-primitives 2.0.0",
 ]

 [[package]]
@@ -6199,6 +6265,7 @@ dependencies = [
 "memory-db 0.15.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "parity-scale-codec 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "serde 1.0.102 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-api 2.0.0",
 "sr-io 2.0.0",
 "sr-primitives 2.0.0",
 "sr-std 2.0.0",
@@ -6210,6 +6277,7 @@ dependencies = [
 "srml-system-rpc-runtime-api 2.0.0",
 "srml-timestamp 2.0.0",
 "substrate-application-crypto 2.0.0",
+ "substrate-block-builder-runtime-api 2.0.0",
 "substrate-client 2.0.0",
 "substrate-consensus-aura-primitives 2.0.0",
 "substrate-consensus-babe-primitives 2.0.0",
@@ -6222,6 +6290,7 @@ dependencies = [
 "substrate-session 2.0.0",
 "substrate-state-machine 2.0.0",
 "substrate-test-runtime-client 2.0.0",
+ "substrate-transaction-pool-runtime-api 2.0.0",
 "substrate-trie 2.0.0",
 "substrate-wasm-builder-runner 1.0.4",
 "trie-db 0.15.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -6233,6 +6302,7 @@ version = "2.0.0"
 dependencies = [
 "parity-scale-codec 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "sr-primitives 2.0.0",
+ "substrate-block-builder 2.0.0",
 "substrate-primitives 2.0.0",
 "substrate-test-client 2.0.0",
 "substrate-test-runtime 2.0.0",
@@ -6265,12 +6335,22 @@ dependencies = [
 "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
 "parity-scale-codec 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-api 2.0.0",
 "sr-primitives 2.0.0",
- "substrate-client 2.0.0",
 "substrate-keyring 2.0.0",
 "substrate-primitives 2.0.0",
 "substrate-test-runtime-client 2.0.0",
 "substrate-transaction-graph 2.0.0",
+ "substrate-transaction-pool-runtime-api 2.0.0",
+]
+
+[[package]]
+name = "substrate-transaction-pool-runtime-api"
+version = "2.0.0"
+dependencies = [
+ "sr-api 2.0.0",
+ "sr-primitives 2.0.0",
+ "substrate-primitives 2.0.0",
 ]

 [[package]]
@@ -6344,7 +6424,7 @@ dependencies = [

 [[package]]
 name = "syn"
-version = "1.0.7"
+version = "1.0.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -6370,7 +6450,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
 "unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

@@ -6444,7 +6524,7 @@ dependencies = [
 "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
 "version_check 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

@@ -6745,7 +6825,9 @@ version = "0.0.1"
 dependencies = [
 "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
 "parity-scale-codec 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-api 2.0.0",
 "sr-primitives 2.0.0",
+ "substrate-block-builder-runtime-api 2.0.0",
 "substrate-cli 2.0.0",
 "substrate-client 2.0.0",
 "substrate-consensus-common 2.0.0",
@@ -7039,7 +7121,7 @@ dependencies = [
 "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
 "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
 "wasm-bindgen-shared 0.2.51 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

@@ -7071,7 +7153,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
 "wasm-bindgen-backend 0.2.51 (registry+https://github.com/rust-lang/crates.io-index)",
 "wasm-bindgen-shared 0.2.51 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -7091,7 +7173,7 @@ dependencies = [
 "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
 "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
 "wasm-bindgen-backend 0.2.51 (registry+https://github.com/rust-lang/crates.io-index)",
 "weedle 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -7889,7 +7971,7 @@ dependencies = [
 "checksum subtle 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "2d67a5a62ba6e01cb2192ff309324cb4875d0c451d55fe2319433abe7a05a8ee"
 "checksum subtle 2.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "ab3af2eb31c42e8f0ccf43548232556c42737e01a96db6e1777b0be108e79799"
 "checksum syn 0.15.44 (registry+https://github.com/rust-lang/crates.io-index)" = "9ca4b3b69a77cbe1ffc9e198781b7acb0c7365a883670e8f1c1bc66fba79a5c5"
-"checksum syn 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)" = "0e7bedb3320d0f3035594b0b723c8a28d7d336a3eda3881db79e61d676fb644c"
+"checksum syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)" = "661641ea2aa15845cddeb97dad000d22070bb5c1fb456b96c1cba883ec691e92"
 "checksum synstructure 0.10.2 (registry+https://github.com/rust-lang/crates.io-index)" = "02353edf96d6e4dc81aea2d8490a7e9db177bf8acb0e951c24940bf866cb313f"
 "checksum synstructure 0.12.1 (registry+https://github.com/rust-lang/crates.io-index)" = "3f085a5855930c0441ca1288cf044ea4aecf4f43a91668abdb870b4ba546a203"
 "checksum sysinfo 0.9.5 (registry+https://github.com/rust-lang/crates.io-index)" = "d5bd3b813d94552a8033c650691645f8dd5a63d614dddd62428a95d3931ef7b6"
@@ -15,6 +15,8 @@ members = [
 	"core/consensus/slots",
 	"core/consensus/uncles",
 	"core/consensus/pow",
+	"core/block-builder",
+	"core/block-builder/runtime-api",
 	"core/executor",
 	"core/executor/runtime-test",
 	"core/externalities",
@@ -36,7 +38,9 @@ members = [
 	"core/service",
 	"core/service/test",
 	"core/session",
-	"core/sr-api-macros",
+	"core/sr-api",
+	"core/sr-api/proc-macro",
+	"core/sr-api/test",
 	"core/sr-arithmetic",
 	"core/sr-io",
 	"core/sr-primitives",
@@ -51,6 +55,7 @@ members = [
 	"core/test-runtime/client",
 	"core/transaction-pool",
 	"core/transaction-pool/graph",
+	"core/transaction-pool/runtime-api",
 	"core/trie",
 	"core/utils/fork-tree",
 	"core/utils/wasm-builder",
@@ -28,3 +28,4 @@ futures-timer = "0.4"
 parking_lot = "0.9.0"
 peerset = { package = "substrate-peerset", path = "../../core/peerset" }
 test-client = { package = "substrate-test-runtime-client", path = "../../core/test-runtime/client" }
+sr-api = { path = "../sr-api" }
@@ -7,15 +7,15 @@ edition = "2018"

 [dependencies]
 codec = { package = "parity-scale-codec", default-features = false, version = "1.0.3" }
-client = { package = "substrate-client", path = "../../client", default-features = false }
+sr-api = { path = "../../sr-api", default-features = false }
 sr-primitives = { path = "../../sr-primitives", default-features = false }
 rstd = { package = "sr-std", path = "../../sr-std", default-features = false }

 [features]
 default = ["std"]
 std = [
-    "rstd/std",
-    "client/std",
-    "codec/std",
-    "sr-primitives/std"
+	"rstd/std",
+	"sr-api/std",
+	"codec/std",
+	"sr-primitives/std"
 ]
@@ -18,7 +18,6 @@

 #![cfg_attr(not(feature = "std"), no_std)]

-use client::decl_runtime_apis;
 use rstd::vec::Vec;
 use sr_primitives::RuntimeDebug;

@@ -29,7 +28,7 @@ pub struct Signature(pub Vec<u8>);
 #[cfg_attr(feature = "std", derive(Hash))]
 pub struct AuthorityId(pub Vec<u8>);

-decl_runtime_apis! {
+sr_api::decl_runtime_apis! {
 	/// The authority discovery api.
 	///
 	/// This api is used by the `core/authority-discovery` module to retrieve our
@@ -105,7 +105,7 @@ where
 	Block: BlockT + Unpin + 'static,
 	Network: NetworkProvider,
 	Client: ProvideRuntimeApi + Send + Sync + 'static + HeaderBackend<Block>,
-	<Client as ProvideRuntimeApi>::Api: AuthorityDiscoveryApi<Block>,
+	<Client as ProvideRuntimeApi>::Api: AuthorityDiscoveryApi<Block, Error = client::error::Error>,
 	Self: Future<Output = ()>,
 {
 	/// Return a new authority discovery.
@@ -303,7 +303,7 @@ where
 	Block: BlockT + Unpin + 'static,
 	Network: NetworkProvider,
 	Client: ProvideRuntimeApi + Send + Sync + 'static + HeaderBackend<Block>,
-	<Client as ProvideRuntimeApi>::Api: AuthorityDiscoveryApi<Block>,
+	<Client as ProvideRuntimeApi>::Api: AuthorityDiscoveryApi<Block, Error = client::error::Error>,
 {
 	type Output = ();

@@ -404,7 +404,7 @@ fn hash_authority_id(id: &[u8]) -> Result<libp2p::kad::record::Key> {
 #[cfg(test)]
 mod tests {
 	use super::*;
-	use client::runtime_api::{ApiExt, Core, RuntimeVersion, StorageProof};
+	use sr_api::{ApiExt, Core, RuntimeVersion, StorageProof};
 	use futures::channel::mpsc::channel;
 	use futures::executor::block_on;
 	use futures::future::poll_fn;
@@ -501,6 +501,8 @@ mod tests {
 	}

 	impl ApiExt<Block> for RuntimeApi {
+		type Error = client::error::Error;
+
 		fn map_api_result<F: FnOnce(&Self) -> std::result::Result<R, E>, R, E>(
 			&self,
 			_: F,
@@ -14,7 +14,8 @@ client = { package = "substrate-client", path = "../../core/client" }
 consensus_common = { package = "substrate-consensus-common", path = "../../core/consensus/common" }
 inherents = { package = "substrate-inherents", path = "../inherents" }
 substrate-telemetry = { path = "../telemetry" }
-transaction_pool = { package = "substrate-transaction-pool", path = "../../core/transaction-pool" }
+transaction_pool = { package = "substrate-transaction-pool", path = "../transaction-pool" }
+block-builder = { package = "substrate-block-builder", path = "../block-builder" }

 [dev-dependencies]
 test-client = { package = "substrate-test-runtime-client", path = "../../core/test-runtime/client" }
@@ -20,10 +20,7 @@
 //

 use std::{time, sync::Arc};
-use client::{
-	error, Client as SubstrateClient, CallExecutor,
-	block_builder::api::BlockBuilder as BlockBuilderApi,
-};
+use client::{error, Client as SubstrateClient, CallExecutor};
 use codec::Decode;
 use consensus_common::{evaluation};
 use inherents::InherentData;
@@ -37,6 +34,7 @@ use sr_primitives::{
 };
 use transaction_pool::txpool::{self, Pool as TransactionPool};
 use substrate_telemetry::{telemetry, CONSENSUS_INFO};
+use block_builder::BlockBuilderApi;

 /// Proposer factory.
 pub struct ProposerFactory<C, A> where A: txpool::ChainApi {
@@ -55,7 +53,8 @@ where
 	Block: BlockT<Hash=H256>,
 	RA: Send + Sync + 'static,
 	SubstrateClient<B, E, Block, RA>: ProvideRuntimeApi,
-	<SubstrateClient<B, E, Block, RA> as ProvideRuntimeApi>::Api: BlockBuilderApi<Block>,
+	<SubstrateClient<B, E, Block, RA> as ProvideRuntimeApi>::Api:
+		BlockBuilderApi<Block, Error = client::error::Error>,
 {
 	type Proposer = Proposer<Block, SubstrateClient<B, E, Block, RA>, A>;
 	type Error = error::Error;
@@ -102,7 +101,8 @@ where
 	Block: BlockT<Hash=H256>,
 	RA: Send + Sync + 'static,
 	SubstrateClient<B, E, Block, RA>: ProvideRuntimeApi,
-	<SubstrateClient<B, E, Block, RA> as ProvideRuntimeApi>::Api: BlockBuilderApi<Block>,
+	<SubstrateClient<B, E, Block, RA> as ProvideRuntimeApi>::Api:
+		BlockBuilderApi<Block, Error = client::error::Error>,
 {
 	type Create = futures::future::Ready<Result<Block, error::Error>>;
 	type Error = error::Error;
@@ -126,7 +126,8 @@ impl<Block, B, E, RA, A> Proposer<Block, SubstrateClient<B, E, Block, RA>, A>	wh
 	Block: BlockT<Hash=H256>,
 	RA: Send + Sync + 'static,
 	SubstrateClient<B, E, Block, RA>: ProvideRuntimeApi,
-	<SubstrateClient<B, E, Block, RA> as ProvideRuntimeApi>::Api: BlockBuilderApi<Block>,
+	<SubstrateClient<B, E, Block, RA> as ProvideRuntimeApi>::Api:
+		BlockBuilderApi<Block, Error = client::error::Error>,
 {
 	fn propose_with(
 		&self,
@@ -167,7 +168,7 @@ impl<Block, B, E, RA, A> Proposer<Block, SubstrateClient<B, E, Block, RA>, A>	wh
 			}

 			trace!("[{:?}] Pushing to the block.", pending.hash);
-			match client::block_builder::BlockBuilder::push(&mut block_builder, pending.data.clone()) {
+			match block_builder::BlockBuilder::push(&mut block_builder, pending.data.clone()) {
 				Ok(()) => {
 					debug!("[{:?}] Pushed to the block.", pending.hash);
 				}
@@ -0,0 +1,14 @@
+[package]
+name = "substrate-block-builder"
+version = "2.0.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2018"
+
+[dependencies]
+state-machine = { package = "substrate-state-machine", path = "../state-machine" }
+sr-primitives = { path = "../sr-primitives" }
+primitives = { package = "substrate-primitives", path = "../primitives" }
+codec = { package = "parity-scale-codec", version = "1.0.6", features = ["derive"] }
+runtime_api = { package = "substrate-block-builder-runtime-api", path = "runtime-api" }
+sr-api = { path = "../sr-api" }
+
@@ -0,0 +1,20 @@
+[package]
+name = "substrate-block-builder-runtime-api"
+version = "2.0.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2018"
+
+[dependencies]
+sr-primitives = { path = "../../sr-primitives", default-features = false }
+sr-api = { path = "../../sr-api", default-features = false }
+rstd = { package = "sr-std", path = "../../sr-std", default-features = false }
+inherents = { package = "substrate-inherents", path = "../../inherents", default-features = false }
+
+[features]
+default = [ "std" ]
+std = [
+	"sr-primitives/std",
+	"inherents/std",
+	"sr-api/std",
+	"rstd/std",
+]
@@ -1,4 +1,4 @@
-// Copyright 2018-2019 Parity Technologies (UK) Ltd.
+// Copyright 2019 Parity Technologies (UK) Ltd.
 // This file is part of Substrate.

 // Substrate is free software: you can redistribute it and/or modify
@@ -14,15 +14,16 @@
 // You should have received a copy of the GNU General Public License
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.

-//! The runtime api for building blocks.
+//! The block builder runtime api.
+
+#![cfg_attr(not(feature = "std"), no_std)]

 use sr_primitives::{traits::Block as BlockT, ApplyResult};
-use rstd::vec::Vec;
-use sr_api_macros::decl_runtime_apis;
-pub use inherents::{InherentData, CheckInherentsResult};

-decl_runtime_apis! {
-	/// The `BlockBuilder` api trait that provides required functions for building a block for a runtime.
+use inherents::{InherentData, CheckInherentsResult};
+
+sr_api::decl_runtime_apis! {
+	/// The `BlockBuilder` api trait that provides the required functionality for building a block.
 	#[api_version(3)]
 	pub trait BlockBuilder {
 		/// Apply the given extrinsics.
@@ -31,7 +32,9 @@ decl_runtime_apis! {
 		#[renamed("finalise_block", 3)]
 		fn finalize_block() -> <Block as BlockT>::Header;
 		/// Generate inherent extrinsics. The inherent data will vary from chain to chain.
-		fn inherent_extrinsics(inherent: InherentData) -> Vec<<Block as BlockT>::Extrinsic>;
+		fn inherent_extrinsics(
+			inherent: InherentData,
+		) -> rstd::vec::Vec<<Block as BlockT>::Extrinsic>;
 		/// Check that the inherents are valid. The inherent data will vary from chain to chain.
 		fn check_inherents(block: Block, data: InherentData) -> CheckInherentsResult;
 		/// Generate a random seed.
@@ -14,59 +14,66 @@
 // You should have received a copy of the GNU General Public License
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.

-use super::api::BlockBuilder as BlockBuilderApi;
-use std::vec::Vec;
+//! Substrate block builder
+//!
+//! This crate provides the [`BlockBuilder`] utility and the corresponding runtime api
+//! [`BlockBuilder`](api::BlockBuilder).
+//!
+//! The block builder utility is used in the node as an abstraction over the runtime api to
+//! initialize a block, to push extrinsics and to finalize a block.
+
+#![warn(missing_docs)]
+
 use codec::Encode;
-use sr_primitives::generic::BlockId;
-use sr_primitives::traits::{
-	Header as HeaderT, Hash, Block as BlockT, One, HashFor, ProvideRuntimeApi, ApiRef, DigestFor,
+
+use sr_primitives::{
+	generic::BlockId,
+	traits::{
+		Header as HeaderT, Hash, Block as BlockT, HashFor, ProvideRuntimeApi, ApiRef, DigestFor,
+		NumberFor, One,
+	},
 };
-use primitives::{H256, ExecutionContext};
+
+use primitives::ExecutionContext;
+
 use state_machine::StorageProof;
-use crate::blockchain::HeaderBackend;
-use crate::runtime_api::{Core, ApiExt};
-use crate::error;
+
+use sr_api::{Core, ApiExt, ApiErrorFor};
+
+pub use runtime_api::BlockBuilder as BlockBuilderApi;
+
+/// Error when the runtime failed to apply an extrinsic.
+pub struct ApplyExtrinsicFailed(pub sr_primitives::ApplyError);

 /// Utility for building new (valid) blocks from a stream of extrinsics.
-pub struct BlockBuilder<'a, Block, A: ProvideRuntimeApi> where Block: BlockT {
-	header: <Block as BlockT>::Header,
-	extrinsics: Vec<<Block as BlockT>::Extrinsic>,
+pub struct BlockBuilder<'a, Block: BlockT, A: ProvideRuntimeApi> {
+	header: Block::Header,
+	extrinsics: Vec<Block::Extrinsic>,
 	api: ApiRef<'a, A::Api>,
 	block_id: BlockId<Block>,
 }

 impl<'a, Block, A> BlockBuilder<'a, Block, A>
 where
-	Block: BlockT<Hash=H256>,
-	A: ProvideRuntimeApi + HeaderBackend<Block> + 'a,
+	Block: BlockT,
+	A: ProvideRuntimeApi + 'a,
 	A::Api: BlockBuilderApi<Block>,
+	ApiErrorFor<A, Block>: From<ApplyExtrinsicFailed>,
 {
-	/// Create a new instance of builder from the given client, building on the
-	/// latest block.
-	pub fn new(api: &'a A, inherent_digests: DigestFor<Block>) -> error::Result<Self> {
-		Self::at_block(&BlockId::Hash(api.info().best_hash), api, false, inherent_digests)
-	}
-
-	/// Create a new instance of builder from the given client using a
-	/// particular block's ID to build upon with optional proof recording enabled.
+	/// Create a new instance of builder based on the given `parent_hash` and `parent_number`.
 	///
 	/// While proof recording is enabled, all accessed trie nodes are saved.
 	/// These recorded trie nodes can be used by a third party to prove the
 	/// output of this block builder without having access to the full storage.
-	pub fn at_block(
-		block_id: &BlockId<Block>,
+	pub fn new(
 		api: &'a A,
+		parent_hash: Block::Hash,
+		parent_number: NumberFor<Block>,
 		proof_recording: bool,
 		inherent_digests: DigestFor<Block>,
-	) -> error::Result<Self> {
-		let number = api.block_number_from_id(block_id)?
-			.ok_or_else(|| error::Error::UnknownBlock(format!("{}", block_id)))?
-			+ One::one();
-
-		let parent_hash = api.block_hash_from_id(block_id)?
-			.ok_or_else(|| error::Error::UnknownBlock(format!("{}", block_id)))?;
+	) -> Result<Self, ApiErrorFor<A, Block>> {
 		let header = <<Block as BlockT>::Header as HeaderT>::new(
-			number,
+			parent_number + One::one(),
 			Default::default(),
 			Default::default(),
 			parent_hash,
@@ -79,22 +86,24 @@ where
 			api.record_proof();
 		}

+		let block_id = BlockId::Hash(parent_hash);
+
 		api.initialize_block_with_context(
-			block_id, ExecutionContext::BlockConstruction, &header,
+			&block_id, ExecutionContext::BlockConstruction, &header,
 		)?;

-		Ok(BlockBuilder {
+		Ok(Self {
 			header,
 			extrinsics: Vec::new(),
 			api,
-			block_id: *block_id,
+			block_id,
 		})
 	}

 	/// Push onto the block's list of extrinsics.
 	///
 	/// This will ensure the extrinsic can be validly executed (by executing it);
-	pub fn push(&mut self, xt: <Block as BlockT>::Extrinsic) -> error::Result<()> {
+	pub fn push(&mut self, xt: <Block as BlockT>::Extrinsic) -> Result<(), ApiErrorFor<A, Block>> {
 		let block_id = &self.block_id;
 		let extrinsics = &mut self.extrinsics;

@@ -109,19 +118,19 @@ where
 					Ok(())
 				}
 				Err(e) => {
-					Err(error::Error::ApplyExtrinsicFailed(e))
+					Err(ApplyExtrinsicFailed(e))?
 				}
 			}
 		})
 	}

 	/// Consume the builder to return a valid `Block` containing all pushed extrinsics.
-	pub fn bake(mut self) -> error::Result<Block> {
+	pub fn bake(mut self) -> Result<Block, ApiErrorFor<A, Block>> {
 		self.bake_impl()?;
 		Ok(<Block as BlockT>::new(self.header, self.extrinsics))
 	}

-	fn bake_impl(&mut self) -> error::Result<()> {
+	fn bake_impl(&mut self) -> Result<(), ApiErrorFor<A, Block>> {
 		self.header = self.api.finalize_block_with_context(
 			&self.block_id, ExecutionContext::BlockConstruction
 		)?;
@@ -141,7 +150,9 @@ where
 	///
 	/// The proof will be `Some(_)`, if proof recording was enabled while creating
 	/// the block builder.
-	pub fn bake_and_extract_proof(mut self) -> error::Result<(Block, Option<StorageProof>)> {
+	pub fn bake_and_extract_proof(mut self)
+		-> Result<(Block, Option<StorageProof>), ApiErrorFor<A, Block>>
+	{
 		self.bake_impl()?;

 		let proof = self.api.extract_proof();
@@ -5,29 +5,30 @@ authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"

 [dependencies]
-derive_more = { version = "0.15.0", optional = true }
-fnv = { version = "1.0.6", optional = true }
-log = { version = "0.4.8", optional = true }
-parking_lot = { version = "0.9.0", optional = true }
-hex-literal = { version = "0.2.1", optional = true }
-futures = { version = "0.1.29", optional = true }
-futures03 = { package = "futures-preview", version = "0.3.0-alpha.19", features = ["compat"], optional = true }
-consensus = { package = "substrate-consensus-common", path = "../consensus/common", optional = true }
-executor = { package = "substrate-executor", path = "../executor", optional = true }
-state-machine = { package = "substrate-state-machine", path = "../state-machine", optional = true }
-keyring = { package = "substrate-keyring", path = "../keyring", optional = true }
-trie = { package = "substrate-trie", path = "../trie", optional = true }
-substrate-telemetry = { path = "../telemetry", optional = true }
-hash-db = { version = "0.15.2", default-features = false }
-kvdb = { git = "https://github.com/paritytech/parity-common", optional = true, rev="b0317f649ab2c665b7987b8475878fc4d2e1f81d" }
-codec = { package = "parity-scale-codec", version = "1.0.0", default-features = false, features = ["derive"] }
-primitives = { package = "substrate-primitives", path = "../primitives", default-features = false }
-sr-primitives = { path = "../sr-primitives", default-features = false }
-runtime-version = { package = "sr-version", path = "../sr-version", default-features = false }
-rstd = { package = "sr-std", path = "../sr-std", default-features = false }
-inherents = { package = "substrate-inherents", path = "../inherents", default-features = false }
-sr-api-macros = { path = "../sr-api-macros" }
-header-metadata = { package = "substrate-header-metadata", path = "header-metadata", optional = true }
+derive_more = { version = "0.15.0" }
+fnv = { version = "1.0.6" }
+log = { version = "0.4.8" }
+parking_lot = { version = "0.9.0" }
+hex-literal = { version = "0.2.1" }
+futures = { version = "0.1.29" }
+futures03 = { package = "futures-preview", version = "0.3.0-alpha.19", features = ["compat"] }
+consensus = { package = "substrate-consensus-common", path = "../consensus/common" }
+executor = { package = "substrate-executor", path = "../executor" }
+state-machine = { package = "substrate-state-machine", path = "../state-machine" }
+keyring = { package = "substrate-keyring", path = "../keyring" }
+trie = { package = "substrate-trie", path = "../trie" }
+substrate-telemetry = { path = "../telemetry" }
+hash-db = { version = "0.15.2" }
+kvdb = { git = "https://github.com/paritytech/parity-common", rev="b0317f649ab2c665b7987b8475878fc4d2e1f81d" }
+codec = { package = "parity-scale-codec", version = "1.0.0", features = ["derive"] }
+primitives = { package = "substrate-primitives", path = "../primitives" }
+sr-primitives = { path = "../sr-primitives" }
+runtime-version = { package = "sr-version", path = "../sr-version" }
+rstd = { package = "sr-std", path = "../sr-std" }
+inherents = { package = "substrate-inherents", path = "../inherents" }
+sr-api = { path = "../sr-api" }
+header-metadata = { package = "substrate-header-metadata", path = "header-metadata" }
+block-builder = { package = "substrate-block-builder", path = "../block-builder" }

 [dev-dependencies]
 env_logger = "0.7.0"
@@ -37,29 +38,3 @@ test-client = { package = "substrate-test-runtime-client", path = "../test-runti
 kvdb-memorydb = { git = "https://github.com/paritytech/parity-common", rev="b0317f649ab2c665b7987b8475878fc4d2e1f81d" }
 panic-handler = { package = "substrate-panic-handler", path = "../panic-handler" }

-[features]
-default = ["std"]
-std = [
-	"rstd/std",
-	"codec/std",
-	"primitives/std",
-	"inherents/std",
-	"sr-primitives/std",
-	"runtime-version/std",
-	"hash-db/std",
-	"header-metadata",
-	"consensus",
-	"parking_lot",
-	"derive_more",
-	"fnv",
-	"log",
-	"hex-literal",
-	"futures",
-	"futures03",
-	"executor",
-	"state-machine",
-	"keyring",
-	"trie",
-	"substrate-telemetry",
-	"kvdb"
-]
@@ -30,7 +30,7 @@ use primitives::{
 	traits::{CodeExecutor, KeystoreExt},
 };

-use crate::runtime_api::{ProofRecorder, InitializeBlock};
+use sr_api::{ProofRecorder, InitializeBlock};
 use crate::backend;
 use crate::error;

@@ -53,11 +53,10 @@ use consensus::{
 };
 use header_metadata::{HeaderMetadata, CachedHeaderMetadata};

+use sr_api::{CallRuntimeAt, ConstructRuntimeApi, Core as CoreApi, ProofRecorder, InitializeBlock};
+use block_builder::BlockBuilderApi;
+
 use crate::{
-	runtime_api::{
-		CallRuntimeAt, ConstructRuntimeApi, Core as CoreApi, ProofRecorder,
-		InitializeBlock,
-	},
 	backend::{
 		self, BlockImportOperation, PrunableStateChangesTrieStorage,
 		ClientImportOperation, Finalizer, ImportSummary,
@@ -70,9 +69,7 @@ use crate::{
 	call_executor::{CallExecutor, LocalCallExecutor},
 	notifications::{StorageNotifications, StorageEventStream},
 	light::{call_executor::prove_execution, fetcher::ChangesProof},
-	block_builder::{self, api::BlockBuilder as BlockBuilderAPI},
-	error::Error,
-	cht, error, in_mem, genesis
+	error::Error, cht, error, in_mem, genesis
 };

 /// Type that implements `futures::Stream` of block import events.
@@ -749,9 +746,16 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 		E: Clone + Send + Sync,
 		RA: Send + Sync,
 		Self: ProvideRuntimeApi,
-		<Self as ProvideRuntimeApi>::Api: BlockBuilderAPI<Block>
+		<Self as ProvideRuntimeApi>::Api: BlockBuilderApi<Block, Error = Error>
 	{
-		block_builder::BlockBuilder::new(self, inherent_digests)
+		let info = self.info();
+		block_builder::BlockBuilder::new(
+			self,
+			info.chain.best_hash,
+			info.chain.best_number,
+			false,
+			inherent_digests,
+		)
 	}

 	/// Create a new block, built on top of `parent`.
@@ -763,9 +767,15 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 		E: Clone + Send + Sync,
 		RA: Send + Sync,
 		Self: ProvideRuntimeApi,
-		<Self as ProvideRuntimeApi>::Api: BlockBuilderAPI<Block>
+		<Self as ProvideRuntimeApi>::Api: BlockBuilderApi<Block, Error = Error>
 	{
-		block_builder::BlockBuilder::at_block(parent, &self, false, inherent_digests)
+		block_builder::BlockBuilder::new(
+			self,
+			self.expect_block_hash_from_id(parent)?,
+			self.expect_block_number_from_id(parent)?,
+			false,
+			inherent_digests,
+		)
 	}

 	/// Create a new block, built on top of `parent` with proof recording enabled.
@@ -781,9 +791,15 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 		E: Clone + Send + Sync,
 		RA: Send + Sync,
 		Self: ProvideRuntimeApi,
-		<Self as ProvideRuntimeApi>::Api: BlockBuilderAPI<Block>
+		<Self as ProvideRuntimeApi>::Api: BlockBuilderApi<Block, Error = Error>
 	{
-		block_builder::BlockBuilder::at_block(parent, &self, true, inherent_digests)
+		block_builder::BlockBuilder::new(
+			self,
+			self.expect_block_hash_from_id(parent)?,
+			self.expect_block_number_from_id(parent)?,
+			true,
+			inherent_digests,
+		)
 	}

 	/// Lock the import lock, and run operations inside.
@@ -1367,7 +1383,7 @@ impl<B, E, Block, RA> ChainHeaderBackend<Block> for Client<B, E, Block, RA> wher
 	B: backend::Backend<Block, Blake2Hasher>,
 	E: CallExecutor<Block, Blake2Hasher> + Send + Sync,
 	Block: BlockT<Hash=H256>,
-	RA: Send + Sync
+	RA: Send + Sync,
 {
 	fn header(&self, id: BlockId<Block>) -> error::Result<Option<Block::Header>> {
 		self.backend.blockchain().header(id)
@@ -1390,6 +1406,23 @@ impl<B, E, Block, RA> ChainHeaderBackend<Block> for Client<B, E, Block, RA> wher
 	}
 }

+impl<B, E, Block, RA> sr_primitives::traits::BlockIdTo<Block> for Client<B, E, Block, RA> where
+	B: backend::Backend<Block, Blake2Hasher>,
+	E: CallExecutor<Block, Blake2Hasher> + Send + Sync,
+	Block: BlockT<Hash=H256>,
+	RA: Send + Sync,
+{
+	type Error = Error;
+
+	fn to_hash(&self, block_id: &BlockId<Block>) -> error::Result<Option<Block::Hash>> {
+		self.block_hash_from_id(block_id)
+	}
+
+	fn to_number(&self, block_id: &BlockId<Block>) -> error::Result<Option<NumberFor<Block>>> {
+		self.block_number_from_id(block_id)
+	}
+}
+
 impl<B, E, Block, RA> ChainHeaderBackend<Block> for &Client<B, E, Block, RA> where
 	B: backend::Backend<Block, Blake2Hasher>,
 	E: CallExecutor<Block, Blake2Hasher> + Send + Sync,
@@ -1444,11 +1477,13 @@ impl<B, E, Block, RA> CallRuntimeAt<Block> for Client<B, E, Block, RA> where
 	E: CallExecutor<Block, Blake2Hasher> + Clone + Send + Sync,
 	Block: BlockT<Hash=H256>,
 {
+	type Error = Error;
+
 	fn call_api_at<
 		'a,
 		R: Encode + Decode + PartialEq,
 		NC: FnOnce() -> result::Result<R, String> + UnwindSafe,
-		C: CoreApi<Block>,
+		C: CoreApi<Block, Error = Error>,
 	>(
 		&self,
 		core_api: &C,
@@ -124,6 +124,12 @@ impl<'a> From<&'a str> for Error {
 	}
 }

+impl From<block_builder::ApplyExtrinsicFailed> for Error {
+	fn from(err: block_builder::ApplyExtrinsicFailed) -> Self {
+		Self::ApplyExtrinsicFailed(err.0)
+	}
+}
+
 impl Error {
 	/// Chain a blockchain error.
 	pub fn from_blockchain(e: Box<Error>) -> Self {
@@ -73,44 +73,25 @@
 //! ```
 //!

-#![cfg_attr(not(feature = "std"), no_std)]
 #![warn(missing_docs)]
 #![recursion_limit="128"]

-#[macro_use]
-pub mod runtime_api;
-#[cfg(feature = "std")]
 pub mod error;
-#[cfg(feature = "std")]
 pub mod blockchain;
-#[cfg(feature = "std")]
 pub mod backend;
-#[cfg(feature = "std")]
 pub mod cht;
-#[cfg(feature = "std")]
 pub mod in_mem;
-#[cfg(feature = "std")]
 pub mod genesis;
-pub mod block_builder;
-#[cfg(feature = "std")]
 pub mod light;
-#[cfg(feature = "std")]
 pub mod leaves;
-#[cfg(feature = "std")]
 pub mod children;
-#[cfg(feature = "std")]
 mod call_executor;
-#[cfg(feature = "std")]
 mod client;
-#[cfg(feature = "std")]
 mod notifications;


-#[cfg(feature = "std")]
 pub use crate::blockchain::Info as ChainInfo;
-#[cfg(feature = "std")]
 pub use crate::call_executor::{CallExecutor, LocalCallExecutor};
-#[cfg(feature = "std")]
 pub use crate::client::{
 	new_with_backend,
 	new_in_mem,
@@ -119,14 +100,7 @@ pub use crate::client::{
 	LongestChain, BlockOf, ProvideUncles, ForkBlocks,
 	utils, apply_aux,
 };
-#[cfg(feature = "std")]
 pub use crate::notifications::{StorageEventStream, StorageChangeSet};
-#[cfg(feature = "std")]
 pub use state_machine::{ExecutionStrategy, StorageProof};
-#[cfg(feature = "std")]
 pub use crate::leaves::LeafSet;
-#[cfg(feature = "std")]
 pub use crate::blockchain::well_known_cache_keys;
-
-#[doc(inline)]
-pub use sr_api_macros::{decl_runtime_apis, impl_runtime_apis};
@@ -33,7 +33,8 @@ use state_machine::{
 };
 use hash_db::Hasher;

-use crate::runtime_api::{ProofRecorder, InitializeBlock};
+use sr_api::{ProofRecorder, InitializeBlock};
+
 use crate::backend::RemoteBackend;
 use crate::call_executor::CallExecutor;
 use crate::error::{Error as ClientError, Result as ClientResult};
@@ -20,13 +20,15 @@ client = { package = "substrate-client", path = "../../client" }
 substrate-telemetry = { path = "../../telemetry" }
 keystore = { package = "substrate-keystore", path = "../../keystore" }
 consensus_common = { package = "substrate-consensus-common", path = "../common" }
-sr-primitives = {  path = "../../sr-primitives" }
+sr-primitives = { path = "../../sr-primitives" }
+sr-api = { path = "../../sr-api" }
 futures-preview = { version = "0.3.0-alpha.19", features = ["compat"] }
 futures01 = { package = "futures", version = "0.1" }
 futures-timer = "0.4.0"
 parking_lot = "0.9.0"
 log = "0.4.8"
 derive_more = "0.15.0"
+block-builder-api = { package = "substrate-block-builder-runtime-api", path = "../../block-builder/runtime-api" }

 [dev-dependencies]
 keyring = { package = "substrate-keyring", path = "../../keyring" }
@@ -7,7 +7,7 @@ edition = "2018"

 [dependencies]
 codec = { package = "parity-scale-codec", version = "1.0.0", default-features = false }
-substrate-client = { path = "../../../client", default-features = false }
+sr-api = { path = "../../../sr-api", default-features = false }
 app-crypto = { package = "substrate-application-crypto", path = "../../../application-crypto", default-features = false }
 rstd = { package = "sr-std", path = "../../../sr-std", default-features = false }
 sr-primitives = { path = "../../../sr-primitives", default-features = false }
@@ -18,6 +18,6 @@ std = [
 	"rstd/std",
 	"codec/std",
 	"sr-primitives/std",
-	"substrate-client/std",
+	"sr-api/std",
 	"app-crypto/std",
 ]
@@ -19,7 +19,6 @@
 #![cfg_attr(not(feature = "std"), no_std)]

 use codec::{Encode, Decode, Codec};
-use substrate_client::decl_runtime_apis;
 use rstd::vec::Vec;
 use sr_primitives::ConsensusEngineId;

@@ -74,7 +73,7 @@ pub enum ConsensusLog<AuthorityId: Codec> {
 	OnDisabled(AuthorityIndex),
 }

-decl_runtime_apis! {
+sr_api::decl_runtime_apis! {
 	/// API necessary for block authorship with aura.
 	pub trait AuraApi<AuthorityId: Codec> {
 		/// Return the slot duration in seconds for Aura.
@@ -39,16 +39,17 @@ use consensus_common::import_queue::{
 	Verifier, BasicQueue, BoxBlockImport, BoxJustificationImport, BoxFinalityProofImport,
 };
 use client::{
-	block_builder::api::BlockBuilder as BlockBuilderApi, blockchain::ProvideCache,
-	runtime_api::ApiExt, error::Result as CResult, backend::AuxStore, BlockOf,
+	blockchain::ProvideCache, error::Result as CResult, backend::AuxStore, BlockOf,
 	well_known_cache_keys::{self, Id as CacheKeyId},
 };

+use block_builder_api::BlockBuilder as BlockBuilderApi;
+
 use sr_primitives::{generic::{BlockId, OpaqueDigestItemId}, Justification};
 use sr_primitives::traits::{Block as BlockT, Header, DigestItemFor, ProvideRuntimeApi, Zero, Member};

 use primitives::crypto::Pair;
-use inherents::{InherentDataProviders, InherentData, RuntimeString};
+use inherents::{InherentDataProviders, InherentData};

 use futures::prelude::*;
 use parking_lot::Mutex;
@@ -65,6 +66,8 @@ use slots::check_equivocation;

 use keystore::KeyStorePtr;

+use sr_api::ApiExt;
+
 pub use aura_primitives::*;
 pub use consensus_common::SyncOracle;
 pub use digest::CompatibleDigestItem;
@@ -85,7 +88,7 @@ impl SlotDuration {
 		A: Codec,
 		B: BlockT,
 		C: AuxStore + ProvideRuntimeApi,
-		C::Api: AuraApi<B, A>,
+		C::Api: AuraApi<B, A, Error = client::error::Error>,
 	{
 		slots::SlotDuration::get_or_compute(client, |a, b| a.slot_duration(b)).map(Self)
 	}
@@ -332,7 +335,7 @@ enum Error<B: BlockT> {
 	TooFarInFuture,
 	Client(client::error::Error),
 	DataProvider(String),
-	Runtime(RuntimeString)
+	Runtime(String),
 }

 fn find_pre_digest<B: BlockT, P: Pair>(header: &B::Header) -> Result<u64, Error<B>>
@@ -438,7 +441,7 @@ impl<C, P, T> AuraVerifier<C, P, T>
 		inherent_data: InherentData,
 		timestamp_now: u64,
 	) -> Result<(), Error<B>>
-		where C: ProvideRuntimeApi, C::Api: BlockBuilderApi<B>
+		where C: ProvideRuntimeApi, C::Api: BlockBuilderApi<B, Error = client::error::Error>
 	{
 		const MAX_TIMESTAMP_DRIFT_SECS: u64 = 60;

@@ -471,7 +474,7 @@ impl<C, P, T> AuraVerifier<C, P, T>
 						thread::sleep(Duration::from_secs(diff));
 						Ok(())
 					},
-					Some(TIError::Other(e)) => Err(Error::Runtime(e)),
+					Some(TIError::Other(e)) => Err(Error::Runtime(e.into())),
 					None => Err(Error::DataProvider(
 						self.inherent_data_providers.error_to_string(&i, &e)
 					)),
@@ -485,7 +488,7 @@ impl<C, P, T> AuraVerifier<C, P, T>
 #[forbid(deprecated)]
 impl<B: BlockT, C, P, T> Verifier<B> for AuraVerifier<C, P, T> where
 	C: ProvideRuntimeApi + Send + Sync + client::backend::AuxStore + ProvideCache<B> + BlockOf,
-	C::Api: BlockBuilderApi<B> + AuraApi<B, AuthorityId<P>>,
+	C::Api: BlockBuilderApi<B> + AuraApi<B, AuthorityId<P>> + ApiExt<B, Error = client::error::Error>,
 	DigestItemFor<B>: CompatibleDigestItem<P>,
 	P: Pair + Send + Sync + 'static,
 	P::Public: Send + Sync + Hash + Eq + Clone + Decode + Encode + Debug + 'static,
@@ -499,7 +502,9 @@ impl<B: BlockT, C, P, T> Verifier<B> for AuraVerifier<C, P, T> where
 		justification: Option<Justification>,
 		mut body: Option<Vec<B::Extrinsic>>,
 	) -> Result<(BlockImportParams<B>, Option<Vec<(CacheKeyId, Vec<u8>)>>), String> {
-		let mut inherent_data = self.inherent_data_providers.create_inherent_data().map_err(String::from)?;
+		let mut inherent_data = self.inherent_data_providers
+			.create_inherent_data()
+			.map_err(|e| e.into_string())?;
 		let (timestamp_now, slot_now, _) = AuraSlotCompatible.extract_timestamp_and_slot(&inherent_data)
 			.map_err(|e| format!("Could not extract timestamp and slot: {:?}", e))?;
 		let hash = header.hash();
@@ -530,7 +535,10 @@ impl<B: BlockT, C, P, T> Verifier<B> for AuraVerifier<C, P, T> where
 					// skip the inherents verification if the runtime API is old.
 					if self.client
 						.runtime_api()
-						.has_api_with::<dyn BlockBuilderApi<B>, _>(&BlockId::Hash(parent_hash), |v| v >= 2)
+						.has_api_with::<dyn BlockBuilderApi<B, Error = ()>, _>(
+							&BlockId::Hash(parent_hash),
+							|v| v >= 2,
+						)
 						.map_err(|e| format!("{:?}", e))?
 					{
 						self.check_inherents(
@@ -667,7 +675,7 @@ pub fn import_queue<B, C, P, T>(
 ) -> Result<AuraImportQueue<B>, consensus_common::Error> where
 	B: BlockT,
 	C: 'static + ProvideRuntimeApi + BlockOf + ProvideCache<B> + Send + Sync + AuxStore,
-	C::Api: BlockBuilderApi<B> + AuraApi<B, AuthorityId<P>>,
+	C::Api: BlockBuilderApi<B> + AuraApi<B, AuthorityId<P>> + ApiExt<B, Error = client::error::Error>,
 	DigestItemFor<B>: CompatibleDigestItem<P>,
 	P: Pair + Send + Sync + 'static,
 	P::Public: Clone + Eq + Send + Sync + Hash + Debug + Encode + Decode,
@@ -21,6 +21,8 @@ substrate-telemetry = { path = "../../telemetry" }
 keystore = { package = "substrate-keystore", path = "../../keystore" }
 srml-babe = { path = "../../../srml/babe" }
 client = { package = "substrate-client", path = "../../client" }
+sr-api = { path = "../../sr-api" }
+block-builder-api = { package = "substrate-block-builder-runtime-api", path = "../../block-builder/runtime-api" }
 header-metadata = { package = "substrate-header-metadata", path = "../../client/header-metadata" }
 consensus-common = { package = "substrate-consensus-common", path = "../common" }
 uncles = { package = "substrate-consensus-uncles", path = "../uncles" }
@@ -44,6 +46,7 @@ substrate-executor = { path = "../../executor" }
 network = { package = "substrate-network", path = "../../network", features = ["test-helpers"]}
 service = { package = "substrate-service", path = "../../service" }
 test-client = { package = "substrate-test-runtime-client", path = "../../test-runtime/client" }
+block-builder = { package = "substrate-block-builder", path = "../../block-builder" }
 tokio = "0.1.22"
 env_logger = "0.7.0"
 tempfile = "3.1.0"
@@ -6,7 +6,7 @@ description = "Primitives for BABE consensus"
 edition = "2018"

 [dependencies]
-substrate-client = { path = "../../../client", default-features = false }
+sr-api = { path = "../../../sr-api", default-features = false }
 rstd = { package = "sr-std", path = "../../../sr-std", default-features = false }
 sr-primitives = {  path = "../../../sr-primitives", default-features = false }
 app-crypto = { package = "substrate-application-crypto", path = "../../../application-crypto", default-features = false }
@@ -19,7 +19,7 @@ default = ["std"]
 std = [
 	"rstd/std",
 	"sr-primitives/std",
-	"substrate-client/std",
+	"sr-api/std",
 	"codec/std",
 	"schnorrkel",
 	"slots",
@@ -24,7 +24,6 @@ mod digest;
 use codec::{Encode, Decode};
 use rstd::vec::Vec;
 use sr_primitives::{ConsensusEngineId, RuntimeDebug};
-use substrate_client::decl_runtime_apis;

 #[cfg(feature = "std")]
 pub use digest::{BabePreDigest, CompatibleDigestItem};
@@ -165,7 +164,7 @@ impl slots::SlotData for BabeConfiguration {
 	const SLOT_KEY: &'static [u8] = b"babe_configuration";
 }

-decl_runtime_apis! {
+sr_api::decl_runtime_apis! {
 	/// API necessary for block authorship with BABE.
 	pub trait BabeApi {
 		/// Return the configuration for BABE. Currently,
@@ -66,7 +66,7 @@ use consensus_common::ImportResult;
 use consensus_common::import_queue::{
 	BoxJustificationImport, BoxFinalityProofImport,
 };
-use sr_primitives::{generic::{BlockId, OpaqueDigestItemId}, Justification, RuntimeString};
+use sr_primitives::{generic::{BlockId, OpaqueDigestItemId}, Justification};
 use sr_primitives::traits::{
 	Block as BlockT, Header, DigestItemFor, ProvideRuntimeApi,
 	Zero,
@@ -75,11 +75,7 @@ use keystore::KeyStorePtr;
 use parking_lot::Mutex;
 use primitives::{Blake2Hasher, H256, Pair};
 use inherents::{InherentDataProviders, InherentData};
-use substrate_telemetry::{
-	telemetry,
-	CONSENSUS_TRACE,
-	CONSENSUS_DEBUG,
-};
+use substrate_telemetry::{telemetry, CONSENSUS_TRACE, CONSENSUS_DEBUG};
 use consensus_common::{
 	self, BlockImport, Environment, Proposer, BlockCheckParams,
 	ForkChoiceStrategy, BlockImportParams, BlockOrigin, Error as ConsensusError,
@@ -91,11 +87,13 @@ use srml_babe::{
 use consensus_common::SelectChain;
 use consensus_common::import_queue::{Verifier, BasicQueue, CacheKeyId};
 use client::{
-	block_builder::api::BlockBuilder as BlockBuilderApi,
 	blockchain::{self, HeaderBackend, ProvideCache}, BlockchainEvents, CallExecutor, Client,
 	error::Result as ClientResult, error::Error as ClientError, backend::{AuxStore, Backend},
 	ProvideUncles,
 };
+
+use block_builder_api::BlockBuilder as BlockBuilderApi;
+
 use slots::{CheckedHeader, check_equivocation};
 use futures::prelude::*;
 use log::{warn, debug, info, trace};
@@ -104,6 +102,8 @@ use epoch_changes::descendent_query;
 use header_metadata::HeaderMetadata;
 use schnorrkel::SignatureError;

+use sr_api::ApiExt;
+
 mod aux_schema;
 mod verification;
 mod epoch_changes;
@@ -167,7 +167,7 @@ enum Error<B: BlockT> {
 	#[display(fmt = "Checking inherents failed: {}", _0)]
 	CheckInherents(String),
 	Client(client::error::Error),
-	Runtime(RuntimeString),
+	Runtime(inherents::Error),
 	ForkTree(Box<fork_tree::Error<client::error::Error>>),
 }

@@ -202,7 +202,7 @@ impl Config {
 	/// Either fetch the slot duration from disk or compute it from the genesis
 	/// state.
 	pub fn get_or_compute<B: BlockT, C>(client: &C) -> ClientResult<Self> where
-		C: AuxStore + ProvideRuntimeApi, C::Api: BabeApi<B>,
+		C: AuxStore + ProvideRuntimeApi, C::Api: BabeApi<B, Error = client::error::Error>,
 	{
 		trace!(target: "babe", "Getting slot duration");
 		match slots::SlotDuration::get_or_compute(client, |a, b| a.configuration(b)).map(Self) {
@@ -554,7 +554,7 @@ impl<B, E, Block: BlockT, RA, PRA> BabeVerifier<B, E, Block, RA, PRA> {
 		block_id: BlockId<Block>,
 		inherent_data: InherentData,
 	) -> Result<(), Error<Block>>
-		where PRA: ProvideRuntimeApi, PRA::Api: BlockBuilderApi<Block>
+		where PRA: ProvideRuntimeApi, PRA::Api: BlockBuilderApi<Block, Error = client::error::Error>
 	{
 		let inherent_res = self.api.runtime_api().check_inherents(
 			&block_id,
@@ -623,7 +623,8 @@ impl<B, E, Block, RA, PRA> Verifier<Block> for BabeVerifier<B, E, Block, RA, PRA
 	E: CallExecutor<Block, Blake2Hasher> + 'static + Clone + Send + Sync,
 	RA: Send + Sync,
 	PRA: ProvideRuntimeApi + Send + Sync + AuxStore + ProvideCache<Block>,
-	PRA::Api: BlockBuilderApi<Block> + BabeApi<Block>,
+	PRA::Api: BlockBuilderApi<Block, Error = client::error::Error>
+		+ BabeApi<Block, Error = client::error::Error>,
 {
 	fn verify(
 		&mut self,
@@ -1141,7 +1142,7 @@ pub fn import_queue<B, E, Block: BlockT<Hash=H256>, I, RA, PRA>(
 	E: CallExecutor<Block, Blake2Hasher> + Clone + Send + Sync + 'static,
 	RA: Send + Sync + 'static,
 	PRA: ProvideRuntimeApi + ProvideCache<Block> + Send + Sync + AuxStore + 'static,
-	PRA::Api: BlockBuilderApi<Block> + BabeApi<Block>,
+	PRA::Api: BlockBuilderApi<Block> + BabeApi<Block> + ApiExt<Block, Error = client::error::Error>,
 {
 	register_babe_inherent_data_provider(&inherent_data_providers, babe_link.config.slot_duration)?;

@@ -23,7 +23,7 @@ use super::*;
 use authorship::claim_slot;

 use babe_primitives::{AuthorityPair, SlotNumber};
-use client::block_builder::BlockBuilder;
+use block_builder::BlockBuilder;
 use consensus_common::NoNetwork as DummyOracle;
 use consensus_common::import_queue::{
 	BoxBlockImport, BoxJustificationImport, BoxFinalityProofImport,
@@ -36,7 +36,7 @@ pub enum Error {
 	FaultyTimer(std::io::Error),
 	/// Error while working with inherent data.
 	#[display(fmt="InherentData error: {}", _0)]
-	InherentData(String),
+	InherentData(inherents::Error),
 	/// Unable to propose a block.
 	#[display(fmt="Unable to create block proposal.")]
 	CannotPropose,
@@ -10,6 +10,7 @@ codec = { package = "parity-scale-codec", version = "1.0.0", features = ["derive
 primitives = { package = "substrate-primitives", path = "../../primitives" }
 sr-primitives = { path = "../../sr-primitives" }
 client = { package = "substrate-client", path = "../../client" }
+block-builder-api = { package = "substrate-block-builder-runtime-api", path = "../../block-builder/runtime-api" }
 srml-timestamp = { path = "../../../srml/timestamp" }
 inherents = { package = "substrate-inherents", path = "../../inherents" }
 pow-primitives = { package = "substrate-consensus-pow-primitives", path = "primitives" }
@@ -6,7 +6,7 @@ description = "Primitives for Aura consensus"
 edition = "2018"

 [dependencies]
-substrate-client = { path = "../../../client", default-features = false }
+sr-api = { path = "../../../sr-api", default-features = false }
 rstd = { package = "sr-std", path = "../../../sr-std", default-features = false }
 sr-primitives = { path = "../../../sr-primitives", default-features = false }
 primitives = { package = "substrate-primitives", path = "../../../primitives", default-features = false }
@@ -16,7 +16,7 @@ codec = { package = "parity-scale-codec", version = "1.0.0", default-features =
 default = ["std"]
 std = [
 	"rstd/std",
-	"substrate-client/std",
+	"sr-api/std",
 	"sr-primitives/std",
 	"primitives/std",
 	"codec/std",
@@ -21,7 +21,6 @@
 use rstd::vec::Vec;
 use sr_primitives::ConsensusEngineId;
 use codec::Decode;
-use substrate_client::decl_runtime_apis;

 /// The `ConsensusEngineId` of PoW.
 pub const POW_ENGINE_ID: ConsensusEngineId = [b'p', b'o', b'w', b'_'];
@@ -48,7 +47,7 @@ impl TotalDifficulty for u128 {
 	}
 }

-decl_runtime_apis! {
+sr_api::decl_runtime_apis! {
 	/// API necessary for timestamp-based difficulty adjustment algorithms.
 	pub trait TimestampApi<Moment: Decode> {
 		/// Return the timestamp in the current block.
@@ -33,10 +33,10 @@ use std::sync::Arc;
 use std::thread;
 use std::collections::HashMap;
 use client::{
-	BlockOf, blockchain::{HeaderBackend, ProvideCache},
-	block_builder::api::BlockBuilder as BlockBuilderApi, backend::AuxStore,
+	BlockOf, blockchain::{HeaderBackend, ProvideCache}, backend::AuxStore,
 	well_known_cache_keys::Id as CacheKeyId,
 };
+use block_builder_api::BlockBuilder as BlockBuilderApi;
 use sr_primitives::{Justification, RuntimeString};
 use sr_primitives::generic::{BlockId, Digest, DigestItem};
 use sr_primitives::traits::{Block as BlockT, Header as HeaderT, ProvideRuntimeApi};
@@ -75,7 +75,7 @@ pub enum Error<B: BlockT> {
 	#[display(fmt = "Error with block built on {:?}: {:?}", _0, _1)]
 	BlockBuiltError(B::Hash, ConsensusError),
 	#[display(fmt = "Creating inherents failed: {}", _0)]
-	CreateInherents(RuntimeString),
+	CreateInherents(inherents::Error),
 	#[display(fmt = "Checking inherents failed: {}", _0)]
 	CheckInherents(String),
 	Client(client::error::Error),
@@ -210,7 +210,7 @@ impl<B: BlockT<Hash=H256>, C, S, Algorithm> PowVerifier<B, C, S, Algorithm> {
 		inherent_data: InherentData,
 		timestamp_now: u64,
 	) -> Result<(), Error<B>> where
-		C: ProvideRuntimeApi, C::Api: BlockBuilderApi<B>
+		C: ProvideRuntimeApi, C::Api: BlockBuilderApi<B, Error = client::error::Error>
 	{
 		const MAX_TIMESTAMP_DRIFT_SECS: u64 = 60;

@@ -248,7 +248,7 @@ impl<B: BlockT<Hash=H256>, C, S, Algorithm> PowVerifier<B, C, S, Algorithm> {

 impl<B: BlockT<Hash=H256>, C, S, Algorithm> Verifier<B> for PowVerifier<B, C, S, Algorithm> where
 	C: ProvideRuntimeApi + Send + Sync + HeaderBackend<B> + AuxStore + ProvideCache<B> + BlockOf,
-	C::Api: BlockBuilderApi<B>,
+	C::Api: BlockBuilderApi<B, Error = client::error::Error>,
 	S: SelectChain<B>,
 	Algorithm: PowAlgorithm<B> + Send + Sync,
 {
@@ -260,8 +260,8 @@ impl<B: BlockT<Hash=H256>, C, S, Algorithm> Verifier<B> for PowVerifier<B, C, S,
 		mut body: Option<Vec<B::Extrinsic>>,
 	) -> Result<(BlockImportParams<B>, Option<Vec<(CacheKeyId, Vec<u8>)>>), String> {
 		let inherent_data = self.inherent_data_providers
-			.create_inherent_data().map_err(String::from)?;
-		let timestamp_now = inherent_data.timestamp_inherent_data().map_err(String::from)?;
+			.create_inherent_data().map_err(|e| e.into_string())?;
+		let timestamp_now = inherent_data.timestamp_inherent_data().map_err(|e| e.into_string())?;

 		let best_hash = match self.select_chain.as_ref() {
 			Some(select_chain) => select_chain.best_chain()
@@ -340,7 +340,7 @@ pub fn import_queue<B, C, S, Algorithm>(
 	B: BlockT<Hash=H256>,
 	C: ProvideRuntimeApi + HeaderBackend<B> + BlockOf + ProvideCache<B> + AuxStore,
 	C: Send + Sync + AuxStore + 'static,
-	C::Api: BlockBuilderApi<B>,
+	C::Api: BlockBuilderApi<B, Error = client::error::Error>,
 	Algorithm: PowAlgorithm<B> + Send + Sync + 'static,
 	S: SelectChain<B> + 'static,
 {
@@ -146,7 +146,7 @@ impl<SC: SlotCompatible + Unpin> Stream for Slots<SC> {

 			let inherent_data = match self.inherent_data_providers.create_inherent_data() {
 				Ok(id) => id,
-				Err(err) => return Poll::Ready(Some(Err(consensus_common::Error::InherentData(err.into_owned())))),
+				Err(err) => return Poll::Ready(Some(Err(consensus_common::Error::InherentData(err)))),
 			};
 			let result = self.timestamp_extractor.extract_timestamp_and_slot(&inherent_data);
 			let (timestamp, slot_num, offset) = match result {
@@ -38,3 +38,4 @@ state_machine = { package = "substrate-state-machine", path = "../state-machine"
 env_logger = "0.7.0"
 tokio = "0.1.22"
 tempfile = "3.1.0"
+sr-api = { path = "../sr-api" }
@@ -5,7 +5,7 @@ authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"

 [dependencies]
-client = { package = "substrate-client", path = "../../client", default-features = false }
+sr-api = { path = "../../sr-api", default-features = false }
 app-crypto = { package = "substrate-application-crypto", path = "../../application-crypto", default-features = false }
 codec = { package = "parity-scale-codec", version = "1.0.0", default-features = false, features = ["derive"] }
 sr-primitives = { path = "../../sr-primitives", default-features = false }
@@ -15,7 +15,7 @@ serde = { version = "1.0.101", optional = true, features = ["derive"] }
 [features]
 default = ["std"]
 std = [
-	"client/std",
+	"sr-api/std",
 	"codec/std",
 	"sr-primitives/std",
 	"rstd/std",
@@ -25,7 +25,6 @@ extern crate alloc;
 use serde::Serialize;
 use codec::{Encode, Decode, Input, Codec};
 use sr_primitives::{ConsensusEngineId, RuntimeDebug};
-use client::decl_runtime_apis;
 use rstd::borrow::Cow;
 use rstd::vec::Vec;

@@ -211,7 +210,7 @@ impl<'a> Decode for VersionedAuthorityList<'a> {
 	}
 }

-decl_runtime_apis! {
+sr_api::decl_runtime_apis! {
 	/// APIs for integrating the GRANDPA finality gadget into runtimes.
 	/// This should be implemented on the runtime side.
 	///
@@ -25,11 +25,8 @@ use parking_lot::Mutex;
 use futures03::{StreamExt as _, TryStreamExt as _};
 use tokio::runtime::current_thread;
 use keyring::Ed25519Keyring;
-use client::{
-	error::Result,
-	runtime_api::{Core, RuntimeVersion, ApiExt, StorageProof},
-	LongestChain,
-};
+use client::{error::Result, LongestChain};
+use sr_api::{Core, RuntimeVersion, ApiExt, StorageProof};
 use test_client::{self, runtime::BlockNumber};
 use consensus_common::{BlockOrigin, ForkChoiceStrategy, ImportedAux, BlockImportParams, ImportResult};
 use consensus_common::import_queue::{BoxBlockImport, BoxJustificationImport, BoxFinalityProofImport};
@@ -244,6 +241,8 @@ impl Core<Block> for RuntimeApi {
 }

 impl ApiExt<Block> for RuntimeApi {
+	type Error = client::error::Error;
+
 	fn map_api_result<F: FnOnce(&Self) -> result::Result<R, E>, R, E>(
 		&self,
 		_: F
@@ -7,8 +7,9 @@ edition = "2018"
 [dependencies]
 parking_lot = { version = "0.9.0", optional = true }
 rstd = { package = "sr-std", path = "../sr-std", default-features = false }
-codec = { package = "parity-scale-codec", version = "1.0.0", default-features = false, features = ["derive"] }
-sr-primitives = {  path = "../sr-primitives", default-features = false }
+primitives = { package = "substrate-primitives", path = "../primitives", default-features = false }
+codec = { package = "parity-scale-codec", version = "1.0.6", default-features = false, features = ["derive"] }
+derive_more = { version = "0.15.0", optional = true }

 [features]
 default = [ "std" ]
@@ -16,5 +17,6 @@ std = [
 	"parking_lot",
 	"rstd/std",
 	"codec/std",
-	"sr-primitives/std",
+	"primitives/std",
+	"derive_more",
 ]
@@ -43,7 +43,37 @@ use parking_lot::RwLock;
 #[cfg(feature = "std")]
 use std::{sync::Arc, format};

-pub use sr_primitives::RuntimeString;
+/// An error that can occur within the inherent data system.
+#[derive(Debug, Encode, Decode, derive_more::Display)]
+#[cfg(feature = "std")]
+pub struct Error(String);
+
+#[cfg(feature = "std")]
+impl<T: Into<String>> From<T> for Error {
+	fn from(data: T) -> Error {
+		Self(data.into())
+	}
+}
+
+#[cfg(feature = "std")]
+impl Error {
+	/// Convert this error into a `String`.
+	pub fn into_string(self) -> String {
+		self.0
+	}
+}
+
+/// An error that can occur within the inherent data system.
+#[derive(Encode, primitives::RuntimeDebug)]
+#[cfg(not(feature = "std"))]
+pub struct Error(&'static str);
+
+#[cfg(not(feature = "std"))]
+impl From<&'static str> for Error {
+	fn from(data: &'static str) -> Error {
+		Self(data)
+	}
+}

 /// An identifier for an inherent.
 pub type InherentIdentifier = [u8; 8];
@@ -73,7 +103,7 @@ impl InherentData {
 		&mut self,
 		identifier: InherentIdentifier,
 		inherent: &I,
-	) -> Result<(), RuntimeString> {
+	) -> Result<(), Error> {
 		match self.data.entry(identifier) {
 			Entry::Vacant(entry) => {
 				entry.insert(inherent.encode());
@@ -106,7 +136,7 @@ impl InherentData {
 	pub fn get_data<I: codec::Decode>(
 		&self,
 		identifier: &InherentIdentifier,
-	) -> Result<Option<I>, RuntimeString> {
+	) -> Result<Option<I>, Error> {
 		match self.data.get(identifier) {
 			Some(inherent) =>
 				I::decode(&mut &inherent[..])
@@ -163,7 +193,7 @@ impl CheckInherentsResult {
 		&mut self,
 		identifier: InherentIdentifier,
 		error: &E,
-	) -> Result<(), RuntimeString> {
+	) -> Result<(), Error> {
 		// Don't accept any other error
 		if self.fatal_error {
 			return Err("No other errors are accepted after an hard error!".into())
@@ -191,7 +221,7 @@ impl CheckInherentsResult {
 	pub fn get_error<E: codec::Decode>(
 		&self,
 		identifier: &InherentIdentifier,
-	) -> Result<Option<E>, RuntimeString> {
+	) -> Result<Option<E>, Error> {
 		self.errors.get_data(identifier)
 	}

@@ -245,7 +275,7 @@ impl InherentDataProviders {
 	pub fn register_provider<P: ProvideInherentData + Send + Sync +'static>(
 		&self,
 		provider: P,
-	) -> Result<(), RuntimeString> {
+	) -> Result<(), Error> {
 		if self.has_provider(&provider.inherent_identifier()) {
 			Err(
 				format!(
@@ -266,7 +296,7 @@ impl InherentDataProviders {
 	}

 	/// Create inherent data.
-	pub fn create_inherent_data(&self) -> Result<InherentData, RuntimeString> {
+	pub fn create_inherent_data(&self) -> Result<InherentData, Error> {
 		let mut data = InherentData::new();
 		self.providers.read().iter().try_for_each(|p| {
 			p.provide_inherent_data(&mut data)
@@ -305,7 +335,7 @@ impl InherentDataProviders {
 pub trait ProvideInherentData {
 	/// Is called when this inherent data provider is registered at the given
 	/// `InherentDataProviders`.
-	fn on_register(&self, _: &InherentDataProviders) -> Result<(), RuntimeString> {
+	fn on_register(&self, _: &InherentDataProviders) -> Result<(), Error> {
 		Ok(())
 	}

@@ -315,7 +345,7 @@ pub trait ProvideInherentData {
 	/// Provide inherent data that should be included in a block.
 	///
 	/// The data should be stored in the given `InherentData` structure.
-	fn provide_inherent_data(&self, inherent_data: &mut InherentData) -> Result<(), RuntimeString>;
+	fn provide_inherent_data(&self, inherent_data: &mut InherentData) -> Result<(), Error>;

 	/// Convert the given encoded error to a string.
 	///
@@ -445,7 +475,7 @@ mod tests {
 	const ERROR_TO_STRING: &str = "Found error!";

 	impl ProvideInherentData for TestInherentDataProvider {
-		fn on_register(&self, _: &InherentDataProviders) -> Result<(), RuntimeString> {
+		fn on_register(&self, _: &InherentDataProviders) -> Result<(), Error> {
 			*self.registered.write() = true;
 			Ok(())
 		}
@@ -454,7 +484,7 @@ mod tests {
 			&TEST_INHERENT_0
 		}

-		fn provide_inherent_data(&self, data: &mut InherentData) -> Result<(), RuntimeString> {
+		fn provide_inherent_data(&self, data: &mut InherentData) -> Result<(), Error> {
 			data.put_data(TEST_INHERENT_0, &42)
 		}

@@ -26,6 +26,7 @@ libp2p = { version = "0.13.0", default-features = false, features = ["libp2p-web
 fork-tree = { path = "../../core/utils/fork-tree" }
 consensus = { package = "substrate-consensus-common", path = "../../core/consensus/common" }
 client = { package = "substrate-client", path = "../../core/client" }
+block-builder = { package = "substrate-block-builder", path = "../../core/block-builder" }
 header_metadata = { package = "substrate-header-metadata", path = "../../core/client/header-metadata" }
 sr-primitives = { path = "../../core/sr-primitives" }
 primitives = { package = "substrate-primitives", path = "../../core/primitives" }
@@ -34,7 +34,7 @@ use client::{
 	error::Result as ClientResult,
 	well_known_cache_keys::{self, Id as CacheKeyId},
 };
-use client::block_builder::BlockBuilder;
+use block_builder::BlockBuilder;
 use client::backend::{AuxStore, Backend, Finalizer};
 use crate::config::Roles;
 use consensus::block_validation::DefaultBlockAnnounceValidator;
@@ -8,7 +8,8 @@ edition = "2018"

 [dependencies]
 bytes = "0.4.12"
-client = { package = "substrate-client", path = "../../core/client" }
+client = { package = "substrate-client", path = "../client" }
+sr-api = { path = "../sr-api" }
 fnv = "1.0.6"
 futures01 = { package = "futures", version = "0.1" }
 futures-preview = "0.3.0-alpha.19"
@@ -7,12 +7,12 @@ authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"

 [dependencies]
-client = { package = "substrate-client", path = "../../client", default-features = false }
+sr-api = { path = "../../sr-api", default-features = false }
 sr-primitives = {  path = "../../sr-primitives", default-features = false }

 [features]
 default = ["std"]
 std = [
-	"client/std",
+	"sr-api/std",
 	"sr-primitives/std"
 ]
@@ -19,13 +19,12 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 #![warn(missing_docs)]

-use client::decl_runtime_apis;
 use sr_primitives::traits::NumberFor;

 /// Local Storage Prefix used by the Offchain Worker API to
 pub const STORAGE_PREFIX: &[u8] = b"storage";

-decl_runtime_apis! {
+sr_api::decl_runtime_apis! {
 	/// The offchain worker api.
 	pub trait OffchainWorkerApi {
 		/// Starts the off-chain task for given block number.
@@ -33,15 +33,11 @@

 #![warn(missing_docs)]

-use std::{
-	fmt,
-	marker::PhantomData,
-	sync::Arc,
-};
+use std::{fmt, marker::PhantomData, sync::Arc};

 use parking_lot::Mutex;
 use threadpool::ThreadPool;
-use client::runtime_api::ApiExt;
+use sr_api::ApiExt;
 use futures::future::Future;
 use log::{debug, warn};
 use network::NetworkStateInfo;
@@ -106,7 +102,7 @@ impl<Client, Storage, Block> OffchainWorkers<
 	) -> impl Future<Output = ()> where A: ChainApi<Block=Block> + 'static {
 		let runtime = self.client.runtime_api();
 		let at = BlockId::number(*number);
-		let has_api = runtime.has_api::<dyn OffchainWorkerApi<Block>>(&at);
+		let has_api = runtime.has_api::<dyn OffchainWorkerApi<Block, Error = ()>>(&at);
 		debug!("Checking offchain workers at {:?}: {:?}", at, has_api);

 		if has_api.unwrap_or(false) {
@@ -38,9 +38,9 @@ use std::borrow::Cow;
 #[cfg(feature = "std")]
 use serde::{Serialize, Deserialize};
 #[cfg(feature = "std")]
-pub use serde;// << for macro
+pub use serde;
 #[doc(hidden)]
-pub use codec::{Encode, Decode};// << for macro
+pub use codec::{Encode, Decode};

 pub use substrate_debug_derive::RuntimeDebug;

@@ -7,6 +7,7 @@ edition = "2018"
 [dependencies]
 api = { package = "substrate-rpc-api", path = "./api" }
 client = { package = "substrate-client", path = "../client" }
+sr-api = { path = "../sr-api" }
 codec = { package = "parity-scale-codec", version = "1.0.0" }
 futures03 = { package = "futures-preview", version = "0.3.0-alpha.19", features = ["compat"] }
 jsonrpc-pubsub = "14.0.3"
@@ -23,7 +23,8 @@ use std::{sync::Arc, convert::TryInto};
 use futures03::future::{FutureExt, TryFutureExt};
 use log::warn;

-use client::{self, Client};
+use client::{Client, error::Error as ClientError};
+
 use rpc::futures::{
 	Sink, Future,
 	future::result,
@@ -87,7 +88,8 @@ impl<B, E, P, RA> AuthorApi<ExHash<P>, BlockHash<P>> for Author<B, E, P, RA> whe
 	P::Error: 'static,
 	RA: Send + Sync + 'static,
 	Client<B, E, P::Block, RA>: ProvideRuntimeApi,
-	<Client<B, E, P::Block, RA> as ProvideRuntimeApi>::Api: SessionKeys<P::Block>,
+	<Client<B, E, P::Block, RA> as ProvideRuntimeApi>::Api:
+		SessionKeys<P::Block, Error = ClientError>,
 {
 	type Metadata = crate::metadata::Metadata;

@@ -131,8 +133,9 @@ impl<B, E, P, RA> AuthorApi<ExHash<P>, BlockHash<P>> for Author<B, E, P, RA> whe
 		Ok(self.pool.ready().map(|tx| tx.data.encode().into()).collect())
 	}

-	fn remove_extrinsic(&self,
-		bytes_or_hash: Vec<hash::ExtrinsicOrHash<ExHash<P>>>
+	fn remove_extrinsic(
+		&self,
+		bytes_or_hash: Vec<hash::ExtrinsicOrHash<ExHash<P>>>,
 	) -> Result<Vec<ExHash<P>>> {
 		let hashes = bytes_or_hash.into_iter()
 			.map(|x| match x {
@@ -155,7 +158,7 @@ impl<B, E, P, RA> AuthorApi<ExHash<P>, BlockHash<P>> for Author<B, E, P, RA> whe
 	fn watch_extrinsic(&self,
 		_metadata: Self::Metadata,
 		subscriber: Subscriber<Status<ExHash<P>, BlockHash<P>>>,
-		xt: Bytes
+		xt: Bytes,
 	) {
 		let submit = || -> Result<_> {
 			let best_block_hash = self.client.info().chain.best_hash;
@@ -24,17 +24,10 @@ mod tests;

 use std::sync::Arc;
 use jsonrpc_pubsub::{typed::Subscriber, SubscriptionId};
-use rpc::{
-	Result as RpcResult,
-	futures::Future,
-};
+use rpc::{Result as RpcResult, futures::Future};

 use api::Subscriptions;
-use client::{
-	Client, CallExecutor,
-	runtime_api::Metadata,
-	light::{blockchain::RemoteBlockchain, fetcher::Fetcher},
-};
+use client::{Client, CallExecutor, light::{blockchain::RemoteBlockchain, fetcher::Fetcher}};
 use primitives::{
 	Blake2Hasher, Bytes, H256,
 	storage::{StorageKey, StorageData, StorageChangeSet},
@@ -44,6 +37,8 @@ use sr_primitives::{
 	traits::{Block as BlockT, ProvideRuntimeApi},
 };

+use sr_api::Metadata;
+
 use self::error::{Error, FutureResult};

 pub use api::state::*;
@@ -188,7 +183,8 @@ pub fn new_full<B, E, Block: BlockT, RA>(
 		E: CallExecutor<Block, Blake2Hasher> + Send + Sync + 'static + Clone,
 		RA: Send + Sync + 'static,
 		Client<B, E, Block, RA>: ProvideRuntimeApi,
-		<Client<B, E, Block, RA> as ProvideRuntimeApi>::Api: Metadata<Block>,
+		<Client<B, E, Block, RA> as ProvideRuntimeApi>::Api:
+			Metadata<Block, Error = client::error::Error>,
 {
 	State {
 		backend: Box::new(self::state_full::FullState::new(client, subscriptions)),
@@ -29,8 +29,7 @@ use rpc::{

 use api::Subscriptions;
 use client::{
-	Client, CallExecutor, BlockchainEvents, runtime_api::Metadata,
-	backend::Backend, error::Result as ClientResult,
+	Client, CallExecutor, BlockchainEvents, backend::Backend, error::Result as ClientResult,
 };
 use primitives::{
 	H256, Blake2Hasher, Bytes, storage::{well_known_keys, StorageKey, StorageData, StorageChangeSet},
@@ -42,6 +41,8 @@ use sr_primitives::{
 	traits::{Block as BlockT, Header, NumberFor, ProvideRuntimeApi, SaturatedConversion},
 };

+use sr_api::Metadata;
+
 use super::{StateBackend, error::{FutureResult, Error, Result}, client_err};

 /// Ranges to query in state_queryStorage.
@@ -229,7 +230,8 @@ impl<B, E, Block, RA> StateBackend<B, E, Block, RA> for FullState<B, E, Block, R
 		E: CallExecutor<Block, Blake2Hasher> + Send + Sync + 'static + Clone,
 		RA: Send + Sync + 'static,
 		Client<B, E, Block, RA>: ProvideRuntimeApi,
-		<Client<B, E, Block, RA> as ProvideRuntimeApi>::Api: Metadata<Block>,
+		<Client<B, E, Block, RA> as ProvideRuntimeApi>::Api:
+			Metadata<Block, Error = client::error::Error>,
 {
 	fn call(
 		&self,
@@ -326,7 +328,9 @@ impl<B, E, Block, RA> StateBackend<B, E, Block, RA> for FullState<B, E, Block, R
 	fn metadata(&self, block: Option<Block::Hash>) -> FutureResult<Bytes> {
 		Box::new(result(
 			self.block_or_best(block)
-				.and_then(|block| self.client.runtime_api().metadata(&BlockId::Hash(block)).map(Into::into))
+				.and_then(|block|
+					self.client.runtime_api().metadata(&BlockId::Hash(block)).map(Into::into)
+				)
 				.map_err(client_err)))
 	}

@@ -10,7 +10,7 @@ default = ["rocksdb"]
 # a path to a database, an error will be produced at runtime.
 rocksdb = ["client_db/kvdb-rocksdb"]
 wasmtime = [
-    "substrate-executor/wasmtime",
+	"substrate-executor/wasmtime",
 ]

 [dependencies]
@@ -38,6 +38,8 @@ consensus_common = { package = "substrate-consensus-common", path = "../../core/
 network = { package = "substrate-network", path = "../../core/network" }
 chain-spec = { package = "substrate-chain-spec", path = "../chain-spec" }
 client = { package = "substrate-client", path = "../../core/client" }
+sr-api = { path = "../sr-api" }
+tx-pool-api = { package = "substrate-transaction-pool-runtime-api", path = "../transaction-pool/runtime-api" }
 client_db = { package = "substrate-client-db", path = "../../core/client/db" }
 codec = { package = "parity-scale-codec", version = "1.0.0" }
 substrate-executor = { path = "../../core/executor" }
@@ -19,8 +19,7 @@ use crate::{SpawnTaskHandle, start_rpc_servers, build_network_future, Transactio
 use crate::status_sinks;
 use crate::config::{Configuration, DatabaseConfig};
 use client::{
-	BlockchainEvents, Client, runtime_api,
-	backend::RemoteBackend, light::blockchain::RemoteBlockchain,
+	BlockchainEvents, Client, backend::RemoteBackend, light::blockchain::RemoteBlockchain,
 };
 use chain_spec::{RuntimeGenesis, Extension};
 use codec::{Decode, Encode, IoReader};
@@ -757,10 +756,11 @@ ServiceBuilder<
 > where
 	Client<TBackend, TExec, TBl, TRtApi>: ProvideRuntimeApi,
 	<Client<TBackend, TExec, TBl, TRtApi> as ProvideRuntimeApi>::Api:
-		runtime_api::Metadata<TBl> +
+		sr_api::Metadata<TBl> +
 		offchain::OffchainWorkerApi<TBl> +
-		runtime_api::TaggedTransactionQueue<TBl> +
-		session::SessionKeys<TBl>,
+		tx_pool_api::TaggedTransactionQueue<TBl> +
+		session::SessionKeys<TBl> +
+		sr_api::ApiExt<TBl, Error = client::error::Error>,
 	TBl: BlockT<Hash = <Blake2Hasher as Hasher>::Out>,
 	TRtApi: 'static + Send + Sync,
 	TCfg: Default,
@@ -808,7 +808,8 @@ ServiceBuilder<

 		session::generate_initial_session_keys(
 			client.clone(),
-			config.dev_key_seed.clone().map(|s| vec![s]).unwrap_or_default()
+			&BlockId::Hash(client.info().chain.best_hash),
+			config.dev_key_seed.clone().map(|s| vec![s]).unwrap_or_default(),
 		)?;

 		let (signal, exit) = exit_future::signal();
@@ -1162,7 +1163,8 @@ pub(crate) fn maintain_transaction_pool<Api, Backend, Block, Executor, PoolApi>(
 	Block: BlockT<Hash = <Blake2Hasher as primitives::Hasher>::Out>,
 	Backend: 'static + client::backend::Backend<Block, Blake2Hasher>,
 	Client<Backend, Executor, Block, Api>: ProvideRuntimeApi,
-	<Client<Backend, Executor, Block, Api> as ProvideRuntimeApi>::Api: runtime_api::TaggedTransactionQueue<Block>,
+	<Client<Backend, Executor, Block, Api> as ProvideRuntimeApi>::Api:
+		tx_pool_api::TaggedTransactionQueue<Block>,
 	Executor: 'static + client::CallExecutor<Block, Blake2Hasher>,
 	PoolApi: 'static + txpool::ChainApi<Hash = Block::Hash, Block = Block>,
 	Api: 'static,
@@ -36,7 +36,7 @@ use std::time::{Duration, Instant};
 use futures::sync::mpsc;
 use parking_lot::Mutex;

-use client::{runtime_api::BlockT, Client};
+use client::Client;
 use exit_future::Signal;
 use futures::prelude::*;
 use futures03::{
@@ -51,7 +51,7 @@ use log::{log, warn, debug, error, Level};
 use codec::{Encode, Decode};
 use primitives::{Blake2Hasher, H256};
 use sr_primitives::generic::BlockId;
-use sr_primitives::traits::NumberFor;
+use sr_primitives::traits::{NumberFor, Block as BlockT};

 pub use self::error::Error;
 pub use self::builder::{ServiceBuilder, ServiceBuilderExport, ServiceBuilderImport, ServiceBuilderRevert};
@@ -5,11 +5,10 @@ authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"

 [dependencies]
-client = { package = "substrate-client", path = "../client", default-features = false }
+sr-api = { path = "../sr-api", default-features = false }
 rstd = { package = "sr-std", path = "../sr-std", default-features = false }
 sr-primitives = { path = "../sr-primitives", optional = true }
-primitives = { package = "substrate-primitives", path = "../primitives", optional = true }

 [features]
 default = [ "std" ]
-std = [ "client/std", "rstd/std", "sr-primitives", "primitives" ]
+std = [ "sr-api/std", "rstd/std", "sr-primitives" ]
@@ -21,11 +21,9 @@
 use rstd::vec::Vec;

 #[cfg(feature = "std")]
-use sr_primitives::traits::{ProvideRuntimeApi, Block as BlockT};
-#[cfg(feature = "std")]
-use primitives::{H256, Blake2Hasher};
+use sr_primitives::{generic::BlockId, traits::{ProvideRuntimeApi, Block as BlockT}};

-client::decl_runtime_apis! {
+sr_api::decl_runtime_apis! {
 	/// Session keys runtime api.
 	pub trait SessionKeys {
 		/// Generate a set of session keys with optionally using the given seed.
@@ -39,28 +37,23 @@ client::decl_runtime_apis! {
 	}
 }

-/// Generate the initial session keys with the given seeds and store them in
+/// Generate the initial session keys with the given seeds, at the given block and store them in
 /// the client's keystore.
 #[cfg(feature = "std")]
-pub fn generate_initial_session_keys<B, E, Block, RA>(
-	client: std::sync::Arc<client::Client<B, E, Block, RA>>,
+pub fn generate_initial_session_keys<Block, T>(
+	client: std::sync::Arc<T>,
+	at: &BlockId<Block>,
 	seeds: Vec<String>,
-) -> Result<(), client::error::Error>
+) -> Result<(), <<T as ProvideRuntimeApi>::Api as sr_api::ApiExt<Block>>::Error>
 where
-	B: client::backend::Backend<Block, Blake2Hasher>,
-	E: client::CallExecutor<Block, Blake2Hasher>,
-	Block: BlockT<Hash=H256>,
-	client::Client<B, E, Block, RA>: ProvideRuntimeApi,
-	<client::Client<B, E, Block, RA> as ProvideRuntimeApi>::Api: SessionKeys<Block>,
+	Block: BlockT,
+	T: ProvideRuntimeApi,
+	<T as ProvideRuntimeApi>::Api: SessionKeys<Block>,
 {
-	let info = client.info().chain;
 	let runtime_api = client.runtime_api();

 	for seed in seeds {
-		runtime_api.generate_session_keys(
-			&sr_primitives::generic::BlockId::Number(info.best_number),
-			Some(seed.as_bytes().to_vec()),
-		)?;
+		runtime_api.generate_session_keys(at, Some(seed.as_bytes().to_vec()))?;
 	}

 	Ok(())
@@ -1,37 +0,0 @@
-[package]
-name = "sr-api-macros"
-version = "2.0.0"
-authors = ["Parity Technologies <admin@parity.io>"]
-edition = "2018"
-
-[lib]
-proc-macro = true
-
-[dependencies]
-quote = "1.0.2"
-syn = { version = "1.0.7", features = [ "full", "fold", "extra-traits", "visit" ] }
-proc-macro2 = "1.0.6"
-blake2-rfc = "0.2.18"
-proc-macro-crate = "0.1.4"
-
-[dev-dependencies]
-client = { package = "substrate-client", path = "../client" }
-test-client = { package = "substrate-test-runtime-client", path = "../test-runtime/client" }
-state_machine = { package = "substrate-state-machine", path = "../state-machine" }
-sr-primitives = {  path = "../sr-primitives" }
-sr-version = { path = "../sr-version" }
-primitives = { package = "substrate-primitives",  path = "../primitives" }
-criterion = "0.3.0"
-consensus_common = { package = "substrate-consensus-common", path = "../consensus/common" }
-codec = { package = "parity-scale-codec", version = "1.0.0" }
-trybuild = "1.0.17"
-rustversion = "1.0.0"
-
-[[bench]]
-name = "bench"
-harness = false
-
-# We actually don't need the `std` feature in this crate, but the tests require it.
-[features]
-default = [ "std" ]
-std = []
@@ -1,5 +0,0 @@
-error: `self` as argument not supported.
- --> $DIR/adding_self_parameter.rs:5:11
-  |
-5 |         fn test(&self);
-  |                 ^
@@ -1,5 +0,0 @@
-error: No api implementation given!
-  --> $DIR/empty_impl_runtime_apis_call.rs:18:1
-   |
-18 | impl_runtime_apis! {}
-   | ^^^^^^^^^^^^^^^^^^^^^ in this macro invocation
@@ -1,64 +0,0 @@
-error[E0053]: method `test` has an incompatible type for trait
-  --> $DIR/impl_incorrect_method_signature.rs:20:17
-   |
-14 |         fn test(data: u64);
-   |                       --- type in trait
-...
-20 |         fn test(data: String) {}
-   |                       ^^^^^^ expected u64, found struct `std::string::String`
-   |
-   = note: expected type `fn(u64)`
-              found type `fn(std::string::String)`
-
-error[E0053]: method `Api_test_runtime_api_impl` has an incompatible type for trait
-  --> $DIR/impl_incorrect_method_signature.rs:18:1
-   |
-12 | / decl_runtime_apis! {
-13 | |     pub trait Api {
-14 | |         fn test(data: u64);
-15 | |     }
-16 | | }
-   | |_- type in trait
-17 | 
-18 |   impl_runtime_apis! {
-   |   -^^^^^^^^^^^^^^^^^
-   |   |
-   |  _expected u64, found struct `std::string::String`
-   | |
-19 | |     impl self::Api<Block> for Runtime {
-20 | |         fn test(data: String) {}
-21 | |     }
-...  |
-33 | |     }
-34 | | }
-   | |_- in this macro invocation
-   |
-   = note: expected type `fn(&RuntimeApiImpl<RuntimeApiImplCall>, &sr_primitives::generic::block::BlockId<sr_primitives::generic::block::Block<sr_primitives::generic::header::Header<u64, sr_primitives::traits::BlakeTwo256>, substrate_test_runtime::Extrinsic>>, sr_api_hidden_includes_DECL_RUNTIME_APIS::sr_api_client::runtime_api::ExecutionContext, std::option::Option<u64>, std::vec::Vec<u8>) -> std::result::Result<sr_api_hidden_includes_DECL_RUNTIME_APIS::sr_api_client::runtime_api::NativeOrEncoded<()>, sr_api_hidden_includes_DECL_RUNTIME_APIS::sr_api_client::error::Error>`
-              found type `fn(&RuntimeApiImpl<RuntimeApiImplCall>, &sr_primitives::generic::block::BlockId<sr_primitives::generic::block::Block<sr_primitives::generic::header::Header<u64, sr_primitives::traits::BlakeTwo256>, substrate_test_runtime::Extrinsic>>, sr_api_hidden_includes_DECL_RUNTIME_APIS::sr_api_client::runtime_api::ExecutionContext, std::option::Option<std::string::String>, std::vec::Vec<u8>) -> std::result::Result<sr_api_hidden_includes_DECL_RUNTIME_APIS::sr_api_client::runtime_api::NativeOrEncoded<()>, sr_api_hidden_includes_DECL_RUNTIME_APIS::sr_api_client::error::Error>`
-
-error[E0308]: mismatched types
-  --> $DIR/impl_incorrect_method_signature.rs:18:1
-   |
-18 | / impl_runtime_apis! {
-19 | |     impl self::Api<Block> for Runtime {
-20 | |         fn test(data: String) {}
-21 | |     }
-...  |
-33 | |     }
-34 | | }
-   | | ^
-   | | |
-   | |_expected u64, found struct `std::string::String`
-   |   in this macro invocation
-   |
-   = note: expected type `u64`
-              found type `std::string::String`
-
-error[E0308]: mismatched types
-  --> $DIR/impl_incorrect_method_signature.rs:20:11
-   |
-20 |         fn test(data: String) {}
-   |                 ^^^^ expected u64, found struct `std::string::String`
-   |
-   = note: expected type `u64`
-              found type `std::string::String`
@@ -1,17 +0,0 @@
-error: Two traits with the same name detected! The trait name is used to generate its ID. Please rename one trait at the declaration!
-  --> $DIR/impl_two_traits_with_same_name.rs:33:15
-   |
-33 |     impl second::Api<Block> for Runtime {
-   |                  ^^^
-
-error[E0277]: the trait bound `RuntimeApiImpl<RuntimeApiImplCall>: sr_api_hidden_includes_DECL_RUNTIME_APIS::sr_api_client::runtime_api::Core<sr_primitives::generic::block::Block<sr_primitives::generic::header::Header<u64, sr_primitives::traits::BlakeTwo256>, substrate_test_runtime::Extrinsic>>` is not satisfied
-  --> $DIR/impl_two_traits_with_same_name.rs:29:7
-   |
-29 |     impl self::Api<Block> for Runtime {
-   |          ^^^^^^^^^^^^^^^^ the trait `sr_api_hidden_includes_DECL_RUNTIME_APIS::sr_api_client::runtime_api::Core<sr_primitives::generic::block::Block<sr_primitives::generic::header::Header<u64, sr_primitives::traits::BlakeTwo256>, substrate_test_runtime::Extrinsic>>` is not implemented for `RuntimeApiImpl<RuntimeApiImplCall>`
-
-error[E0277]: the trait bound `RuntimeApiImpl<RuntimeApiImplCall>: sr_api_hidden_includes_DECL_RUNTIME_APIS::sr_api_client::runtime_api::Core<sr_primitives::generic::block::Block<sr_primitives::generic::header::Header<u64, sr_primitives::traits::BlakeTwo256>, substrate_test_runtime::Extrinsic>>` is not satisfied
-  --> $DIR/impl_two_traits_with_same_name.rs:33:7
-   |
-33 |     impl second::Api<Block> for Runtime {
-   |          ^^^^^^^^^^^^^^^^^^ the trait `sr_api_hidden_includes_DECL_RUNTIME_APIS::sr_api_client::runtime_api::Core<sr_primitives::generic::block::Block<sr_primitives::generic::header::Header<u64, sr_primitives::traits::BlakeTwo256>, substrate_test_runtime::Extrinsic>>` is not implemented for `RuntimeApiImpl<RuntimeApiImplCall>`
@@ -1,33 +0,0 @@
-error: can't qualify macro invocation with `pub`
- --> $DIR/invalid_api_version_2.rs:3:1
-  |
-3 | / decl_runtime_apis! {
-4 | |     #[api_version("1")]
-5 | |     pub trait Api {
-6 | |         fn test(data: u64);
-7 | |     }
-8 | | }
-  | | ^ in this macro invocation
-  | |_|
-  | 
-  |
-  = help: try adjusting the macro to put `pub` inside the invocation
-
-error: Unexpected `api_version` attribute. The supported format is `api_version(1)`
- --> $DIR/invalid_api_version_2.rs:3:1
-  |
-3 | / decl_runtime_apis! {
-4 | |     #[api_version("1")]
-5 | |     pub trait Api {
-6 | |         fn test(data: u64);
-7 | |     }
-8 | | }
-  | | ^ in this macro invocation
-  | |_|
-  | 
-
-error: Unexpected `api_version` attribute. The supported format is `api_version(1)`
- --> $DIR/invalid_api_version_2.rs:4:4
-  |
-4 |     #[api_version("1")]
-  |       ^^^^^^^^^^^
@@ -1,33 +0,0 @@
-error: can't qualify macro invocation with `pub`
- --> $DIR/invalid_api_version_3.rs:3:1
-  |
-3 | / decl_runtime_apis! {
-4 | |     #[api_version()]
-5 | |     pub trait Api {
-6 | |         fn test(data: u64);
-7 | |     }
-8 | | }
-  | | ^ in this macro invocation
-  | |_|
-  | 
-  |
-  = help: try adjusting the macro to put `pub` inside the invocation
-
-error: Unexpected `api_version` attribute. The supported format is `api_version(1)`
- --> $DIR/invalid_api_version_3.rs:3:1
-  |
-3 | / decl_runtime_apis! {
-4 | |     #[api_version()]
-5 | |     pub trait Api {
-6 | |         fn test(data: u64);
-7 | |     }
-8 | | }
-  | | ^ in this macro invocation
-  | |_|
-  | 
-
-error: Unexpected `api_version` attribute. The supported format is `api_version(1)`
- --> $DIR/invalid_api_version_3.rs:4:4
-  |
-4 |     #[api_version()]
-  |       ^^^^^^^^^^^
@@ -1,13 +0,0 @@
-error: Missing `Block` generic parameter.
-  --> $DIR/missing_block_generic_parameter.rs:19:13
-   |
-19 |     impl self::Api for Runtime {
-   |                ^^^
-
-error[E0107]: wrong number of type arguments: expected 1, found 0
-  --> $DIR/missing_block_generic_parameter.rs:19:7
-   |
-19 |     impl self::Api for Runtime {
-   |          ^^^^^^^^^ expected 1 type argument
-
-For more information about this error, try `rustc --explain E0107`.
@@ -1,67 +0,0 @@
-error[E0053]: method `test` has an incompatible type for trait
-  --> $DIR/type_reference_in_impl_runtime_apis_call.rs:20:17
-   |
-14 |         fn test(data: u64);
-   |                       --- type in trait
-...
-20 |         fn test(data: &u64) {
-   |                       ^^^^ expected u64, found &u64
-   |
-   = note: expected type `fn(u64)`
-              found type `fn(&u64)`
-
-error[E0053]: method `Api_test_runtime_api_impl` has an incompatible type for trait
-  --> $DIR/type_reference_in_impl_runtime_apis_call.rs:18:1
-   |
-12 | / decl_runtime_apis! {
-13 | |     pub trait Api {
-14 | |         fn test(data: u64);
-15 | |     }
-16 | | }
-   | |_- type in trait
-17 | 
-18 |   impl_runtime_apis! {
-   |   -^^^^^^^^^^^^^^^^^
-   |   |
-   |  _expected u64, found &u64
-   | |
-19 | |     impl self::Api<Block> for Runtime {
-20 | |         fn test(data: &u64) {
-21 | |             unimplemented!()
-...  |
-35 | |     }
-36 | | }
-   | |_- in this macro invocation
-   |
-   = note: expected type `fn(&RuntimeApiImpl<RuntimeApiImplCall>, &sr_primitives::generic::block::BlockId<sr_primitives::generic::block::Block<sr_primitives::generic::header::Header<u64, sr_primitives::traits::BlakeTwo256>, substrate_test_runtime::Extrinsic>>, sr_api_hidden_includes_DECL_RUNTIME_APIS::sr_api_client::runtime_api::ExecutionContext, std::option::Option<u64>, std::vec::Vec<u8>) -> std::result::Result<sr_api_hidden_includes_DECL_RUNTIME_APIS::sr_api_client::runtime_api::NativeOrEncoded<()>, sr_api_hidden_includes_DECL_RUNTIME_APIS::sr_api_client::error::Error>`
-              found type `fn(&RuntimeApiImpl<RuntimeApiImplCall>, &sr_primitives::generic::block::BlockId<sr_primitives::generic::block::Block<sr_primitives::generic::header::Header<u64, sr_primitives::traits::BlakeTwo256>, substrate_test_runtime::Extrinsic>>, sr_api_hidden_includes_DECL_RUNTIME_APIS::sr_api_client::runtime_api::ExecutionContext, std::option::Option<&u64>, std::vec::Vec<u8>) -> std::result::Result<sr_api_hidden_includes_DECL_RUNTIME_APIS::sr_api_client::runtime_api::NativeOrEncoded<()>, sr_api_hidden_includes_DECL_RUNTIME_APIS::sr_api_client::error::Error>`
-
-error[E0308]: mismatched types
-  --> $DIR/type_reference_in_impl_runtime_apis_call.rs:18:1
-   |
-18 | / impl_runtime_apis! {
-19 | |     impl self::Api<Block> for Runtime {
-20 | |         fn test(data: &u64) {
-21 | |             unimplemented!()
-...  |
-35 | |     }
-36 | | }
-   | | ^
-   | | |
-   | |_expected u64, found &u64
-   |   in this macro invocation
-   |
-   = note: expected type `u64`
-              found type `&u64`
-
-error[E0308]: mismatched types
-  --> $DIR/type_reference_in_impl_runtime_apis_call.rs:20:11
-   |
-20 |         fn test(data: &u64) {
-   |                 ^^^^^^^
-   |                 |
-   |                 expected u64, found &u64
-   |                 help: consider removing the borrow: `data`
-   |
-   = note: expected type `u64`
-              found type `&u64`
@@ -0,0 +1,33 @@
+[package]
+name = "sr-api"
+version = "2.0.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2018"
+
+[dependencies]
+codec = { package = "parity-scale-codec", version = "1.0.0", default-features = false }
+sr-api-proc-macro = { path = "proc-macro" }
+primitives = { package = "substrate-primitives", path = "../primitives", default-features = false }
+rstd = { package = "sr-std", path = "../sr-std", default-features = false }
+sr-primitives = { path = "../sr-primitives", default-features = false }
+sr-version = { path = "../sr-version", default-features = false }
+state-machine = { package = "substrate-state-machine", path = "../state-machine", optional = true }
+
+[dev-dependencies]
+criterion = "0.3.0"
+test-client = { package = "substrate-test-runtime-client", path = "../test-runtime/client" }
+
+[[bench]]
+name = "bench"
+harness = false
+
+[features]
+default = [ "std" ]
+std = [
+	"codec/std",
+	"primitives/std",
+	"rstd/std",
+	"sr-primitives/std",
+	"state-machine",
+	"sr-version/std",
+]
@@ -16,8 +16,8 @@

 use criterion::{Criterion, criterion_group, criterion_main};
 use test_client::{
-    DefaultTestClientBuilderExt, TestClientBuilder,
-    TestClientBuilderExt, runtime::TestAPI,
+	DefaultTestClientBuilderExt, TestClientBuilder,
+	TestClientBuilderExt, runtime::TestAPI,
 };
 use sr_primitives::{generic::BlockId, traits::ProvideRuntimeApi};
 use state_machine::ExecutionStrategy;
@@ -0,0 +1,26 @@
+[package]
+name = "sr-api-proc-macro"
+version = "2.0.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2018"
+
+[lib]
+proc-macro = true
+
+[dependencies]
+quote = "1.0.2"
+syn = { version = "1.0.8", features = [ "full", "fold", "extra-traits", "visit" ] }
+proc-macro2 = "1.0.6"
+blake2-rfc = "0.2.18"
+proc-macro-crate = "0.1.4"
+
+[dev-dependencies]
+sr-api = { path = ".." }
+sr-primitives = { path = "../../sr-primitives" }
+sr-version = { path = "../../sr-version" }
+test-client = { package = "substrate-test-runtime-client", path = "../../test-runtime/client" }
+
+# Required for the doc tests
+[features]
+default = [ "std" ]
+std = []
@@ -96,7 +96,7 @@ fn extend_generics_with_block(generics: &mut Generics) {
 	let c = generate_crate_access(HIDDEN_INCLUDES_ID);

 	generics.lt_token = Some(Default::default());
-	generics.params.insert(0, parse_quote!( Block: #c::runtime_api::BlockT ));
+	generics.params.insert(0, parse_quote!( Block: #c::BlockT ));
 	generics.gt_token = Some(Default::default());
 }

@@ -186,12 +186,12 @@ fn generate_native_call_generators(decl: &ItemTrait) -> Result<TokenStream> {
 	result.push(quote!(
 		#[cfg(any(feature = "std", test))]
 		fn convert_between_block_types
-			<I: #crate_::runtime_api::Encode, R: #crate_::runtime_api::Decode>(
+			<I: #crate_::Encode, R: #crate_::Decode>(
 				input: &I, error_desc: &'static str,
 			) -> std::result::Result<R, String>
 		{
-			<R as #crate_::runtime_api::Decode>::decode(
-				&mut &#crate_::runtime_api::Encode::encode(input)[..],
+			<R as #crate_::Decode>::decode(
+				&mut &#crate_::Encode::encode(input)[..],
 			).map_err(|e| format!("{} {}", error_desc, e.what()))
 		}
 	));
@@ -272,7 +272,7 @@ fn generate_native_call_generators(decl: &ItemTrait) -> Result<TokenStream> {
 		result.push(quote!(
 			#[cfg(any(feature = "std", test))]
 			pub fn #fn_name<
-				'a, ApiImpl: #trait_ #ty_generics, NodeBlock: #crate_::runtime_api::BlockT
+				'a, ApiImpl: #trait_ #ty_generics, NodeBlock: #crate_::BlockT
 				#(, #impl_generics_params)*
 			>(
 				#( #fn_inputs ),*
@@ -396,24 +396,24 @@ fn generate_call_api_at_calls(decl: &ItemTrait) -> Result<TokenStream> {
 		result.push(quote!(
 			#[cfg(any(feature = "std", test))]
 			pub fn #fn_name<
-				R: #crate_::runtime_api::Encode + #crate_::runtime_api::Decode + PartialEq,
+				R: #crate_::Encode + #crate_::Decode + PartialEq,
 				NC: FnOnce() -> std::result::Result<R, String> + std::panic::UnwindSafe,
-				Block: #crate_::runtime_api::BlockT,
-				T: #crate_::runtime_api::CallRuntimeAt<Block>,
-				C: #crate_::runtime_api::Core<Block>,
+				Block: #crate_::BlockT,
+				T: #crate_::CallRuntimeAt<Block>,
+				C: #crate_::Core<Block, Error = T::Error>,
 			>(
 				call_runtime_at: &T,
 				core_api: &C,
-				at: &#crate_::runtime_api::BlockId<Block>,
+				at: &#crate_::BlockId<Block>,
 				args: Vec<u8>,
-				changes: &std::cell::RefCell<#crate_::runtime_api::OverlayedChanges>,
-				initialized_block: &std::cell::RefCell<Option<#crate_::runtime_api::BlockId<Block>>>,
+				changes: &std::cell::RefCell<#crate_::OverlayedChanges>,
+				initialized_block: &std::cell::RefCell<Option<#crate_::BlockId<Block>>>,
 				native_call: Option<NC>,
-				context: #crate_::runtime_api::ExecutionContext,
-				recorder: &Option<std::rc::Rc<std::cell::RefCell<#crate_::runtime_api::ProofRecorder<Block>>>>,
-			) -> #crate_::error::Result<#crate_::runtime_api::NativeOrEncoded<R>> {
+				context: #crate_::ExecutionContext,
+				recorder: &Option<std::rc::Rc<std::cell::RefCell<#crate_::ProofRecorder<Block>>>>,
+			) -> std::result::Result<#crate_::NativeOrEncoded<R>, T::Error> {
 				let version = call_runtime_at.runtime_version_at(at)?;
-				use #crate_::runtime_api::InitializeBlock;
+				use #crate_::InitializeBlock;
 				let initialize_block = if #skip_initialize_block {
 					InitializeBlock::Skip
 				} else {
@@ -553,7 +553,7 @@ impl<'a> ToClientSideDecl<'a> {
 	fn fold_trait_item_method(&mut self, method: TraitItemMethod)
 		-> (TraitItemMethod, Option<TraitItemMethod>, TraitItemMethod) {
 		let crate_ = self.crate_;
-		let context = quote!( #crate_::runtime_api::ExecutionContext::OffchainCall(None) );
+		let context = quote!( #crate_::ExecutionContext::OffchainCall(None) );
 		let fn_impl = self.create_method_runtime_api_impl(method.clone());
 		let fn_decl = self.create_method_decl(method.clone(), context);
 		let fn_decl_ctx = self.create_method_decl_with_context(method);
@@ -563,7 +563,7 @@ impl<'a> ToClientSideDecl<'a> {

 	fn create_method_decl_with_context(&mut self, method: TraitItemMethod) -> TraitItemMethod {
 		let crate_ = self.crate_;
-		let context_arg: syn::FnArg = parse_quote!( context: #crate_::runtime_api::ExecutionContext );
+		let context_arg: syn::FnArg = parse_quote!( context: #crate_::ExecutionContext );
 		let mut fn_decl_ctx = self.create_method_decl(method, quote!( context ));
 		fn_decl_ctx.sig.ident = Ident::new(&format!("{}_with_context", &fn_decl_ctx.sig.ident), Span::call_site());
 		fn_decl_ctx.sig.inputs.insert(2, context_arg);
@@ -604,10 +604,10 @@ impl<'a> ToClientSideDecl<'a> {
 				fn #name(
 					&self,
 					at: &#block_id,
-					context: #crate_::runtime_api::ExecutionContext,
+					context: #crate_::ExecutionContext,
 					params: Option<( #( #param_types ),* )>,
 					params_encoded: Vec<u8>,
-				) -> #crate_::error::Result<#crate_::runtime_api::NativeOrEncoded<#ret_type>>;
+				) -> std::result::Result<#crate_::NativeOrEncoded<#ret_type>, Self::Error>;
 			}
 		)
 	}
@@ -630,7 +630,7 @@ impl<'a> ToClientSideDecl<'a> {
 		let params2 = params.clone();
 		let ret_type = return_type_extract_type(&method.sig.output);

-		fold_fn_decl_for_client_side(&mut method.sig, &self.block_id, &self.crate_);
+		fold_fn_decl_for_client_side(&mut method.sig, &self.block_id);

 		let name_impl = generate_method_runtime_api_impl_name(&self.trait_, &method.sig.ident);
 		let crate_ = self.crate_;
@@ -674,7 +674,7 @@ impl<'a> ToClientSideDecl<'a> {
 			parse_quote! {
 				{
 					let runtime_api_impl_params_encoded =
-						#crate_::runtime_api::Encode::encode(&( #( &#params ),* ));
+						#crate_::Encode::encode(&( #( &#params ),* ));

 					self.#name_impl(
 						__runtime_api_at_param__,
@@ -683,14 +683,16 @@ impl<'a> ToClientSideDecl<'a> {
 						runtime_api_impl_params_encoded,
 					).and_then(|r|
 						match r {
-							#crate_::runtime_api::NativeOrEncoded::Native(n) => {
+							#crate_::NativeOrEncoded::Native(n) => {
 								#native_handling
 							},
-							#crate_::runtime_api::NativeOrEncoded::Encoded(r) => {
-								<#ret_type as #crate_::runtime_api::Decode>::decode(&mut &r[..])
+							#crate_::NativeOrEncoded::Encoded(r) => {
+								<#ret_type as #crate_::Decode>::decode(&mut &r[..])
 									.map_err(|err|
-										#crate_::error::Error::CallResultDecode(
-											#function_name, err
+										format!(
+											"Failed to decode result of `{}`: {}",
+											#function_name,
+											err.what(),
 										).into()
 									)
 							}
@@ -720,12 +722,12 @@ impl<'a> Fold for ToClientSideDecl<'a> {
 				'static
 				+ Send
 				+ Sync
-				+ #crate_::runtime_api::ApiExt<#block_ident>
+				+ #crate_::ApiExt<#block_ident>
 			);
 		} else {
 			// Add the `Core` runtime api as super trait.
 			let crate_ = &self.crate_;
-			input.supertraits.push(parse_quote!( #crate_::runtime_api::Core<#block_ident> ));
+			input.supertraits.push(parse_quote!( #crate_::Core<#block_ident> ));
 		}

 		// The client side trait is only required when compiling with the feature `std` or `test`.
@@ -783,12 +785,24 @@ fn generate_runtime_info_impl(trait_: &ItemTrait, version: u64) -> TokenStream {
 	let crate_ = generate_crate_access(HIDDEN_INCLUDES_ID);
 	let id = generate_runtime_api_id(&trait_name.to_string());
 	let version = generate_runtime_api_version(version as u32);
-	let (impl_generics, ty_generics, where_clause) = trait_.generics.split_for_impl();
+
+	let impl_generics = trait_.generics.type_params().map(|t| {
+		let ident = &t.ident;
+		let colon_token = &t.colon_token;
+		let bounds = &t.bounds;
+
+		quote! { #ident #colon_token #bounds }
+	}).chain(std::iter::once(quote! { __Sr_Api_Error__ }));
+
+	let ty_generics = trait_.generics.type_params().map(|t| {
+		let ident = &t.ident;
+		quote! { #ident }
+	}).chain(std::iter::once(quote! { Error = __Sr_Api_Error__ }));

 	quote!(
 		#[cfg(any(feature = "std", test))]
-		impl #impl_generics #crate_::runtime_api::RuntimeApiInfo
-			for #trait_name #ty_generics #where_clause
+		impl < #( #impl_generics, )* > #crate_::RuntimeApiInfo
+			for #trait_name < #( #ty_generics, )* >
 		{
 			#id
 			#version
@@ -816,7 +830,7 @@ fn generate_client_side_decls(decls: &[ItemTrait]) -> TokenStream {
 		let decl = decl.clone();

 		let crate_ = generate_crate_access(HIDDEN_INCLUDES_ID);
-		let block_id = quote!( #crate_::runtime_api::BlockId<Block> );
+		let block_id = quote!( #crate_::BlockId<Block> );
 		let mut found_attributes = HashMap::new();
 		let mut errors = Vec::new();
 		let trait_ = decl.ident.clone();
@@ -76,7 +76,7 @@ fn generate_impl_call(
 	Ok(
 		quote!(
 			#(
-				let #pnames : #ptypes = match #c_iter::runtime_api::Decode::decode(&mut #input) {
+				let #pnames : #ptypes = match #c_iter::Decode::decode(&mut #input) {
 					Ok(input) => input,
 					Err(e) => panic!("Bad input data provided to {}: {}", #fn_name_str, e.what()),
 				};
@@ -175,7 +175,7 @@ fn generate_dispatch_function(impls: &[ItemImpl]) -> Result<TokenStream> {
 		.into_iter()
 		.map(|(trait_, fn_name, impl_)| {
 			let name = prefix_function_with_trait(&trait_, &fn_name);
-			quote!( #name => Some(#c::runtime_api::Encode::encode(&{ #impl_ })), )
+			quote!( #name => Some(#c::Encode::encode(&{ #impl_ })), )
 		});

 	Ok(quote!(
@@ -209,12 +209,12 @@ fn generate_wasm_interface(impls: &[ItemImpl]) -> Result<TokenStream> {
 						&[0u8; 0]
 					} else {
 						unsafe {
-							#c::runtime_api::slice::from_raw_parts(input_data, input_len)
+							#c::slice::from_raw_parts(input_data, input_len)
 						}
 					};

 					let output = { #impl_ };
-					#c::runtime_api::to_substrate_wasm_fn_return_value(&output)
+					#c::to_substrate_wasm_fn_return_value(&output)
 				}
 			)
 		});
@@ -231,8 +231,8 @@ fn generate_block_and_block_id_ty(
 	let trait_ = Ident::new(trait_, Span::call_site());
 	let assoc_type = Ident::new(assoc_type, Span::call_site());

-	let block = quote!( <#runtime as #crate_::runtime_api::#trait_>::#assoc_type );
-	let block_id = quote!( #crate_::runtime_api::BlockId<#block> );
+	let block = quote!( <#runtime as #crate_::#trait_>::#assoc_type );
+	let block_id = quote!( #crate_::BlockId<#block> );

 	(block, block_id)
 }
@@ -252,30 +252,30 @@ fn generate_runtime_api_base_structures(impls: &[ItemImpl]) -> Result<TokenStrea
 		pub struct RuntimeApi {}
 		/// Implements all runtime apis for the client side.
 		#[cfg(any(feature = "std", test))]
-		pub struct RuntimeApiImpl<C: #crate_::runtime_api::CallRuntimeAt<#block> + 'static> {
+		pub struct RuntimeApiImpl<C: #crate_::CallRuntimeAt<#block> + 'static> {
 			call: &'static C,
 			commit_on_success: std::cell::RefCell<bool>,
 			initialized_block: std::cell::RefCell<Option<#block_id>>,
-			changes: std::cell::RefCell<#crate_::runtime_api::OverlayedChanges>,
-			recorder: Option<std::rc::Rc<std::cell::RefCell<#crate_::runtime_api::ProofRecorder<#block>>>>,
+			changes: std::cell::RefCell<#crate_::OverlayedChanges>,
+			recorder: Option<std::rc::Rc<std::cell::RefCell<#crate_::ProofRecorder<#block>>>>,
 		}

 		// `RuntimeApi` itself is not threadsafe. However, an instance is only available in a
 		// `ApiRef` object and `ApiRef` also has an associated lifetime. This lifetimes makes it
 		// impossible to move `RuntimeApi` into another thread.
 		#[cfg(any(feature = "std", test))]
-		unsafe impl<C: #crate_::runtime_api::CallRuntimeAt<#block>> Send for RuntimeApiImpl<C> {}
+		unsafe impl<C: #crate_::CallRuntimeAt<#block>> Send for RuntimeApiImpl<C> {}
 		#[cfg(any(feature = "std", test))]
-		unsafe impl<C: #crate_::runtime_api::CallRuntimeAt<#block>> Sync for RuntimeApiImpl<C> {}
+		unsafe impl<C: #crate_::CallRuntimeAt<#block>> Sync for RuntimeApiImpl<C> {}

 		#[cfg(any(feature = "std", test))]
-		impl<C: #crate_::runtime_api::CallRuntimeAt<#block>> #crate_::runtime_api::ApiExt<#block>
-			for RuntimeApiImpl<C>
-		{
+		impl<C: #crate_::CallRuntimeAt<#block>> #crate_::ApiExt<#block> for RuntimeApiImpl<C> {
+			type Error = C::Error;
+
 			fn map_api_result<F: FnOnce(&Self) -> std::result::Result<R, E>, R, E>(
 				&self,
 				map_call: F
-			) -> ::std::result::Result<R, E> where Self: Sized {
+			) -> std::result::Result<R, E> where Self: Sized {
 				*self.commit_on_success.borrow_mut() = false;
 				let res = map_call(self);
 				*self.commit_on_success.borrow_mut() = true;
@@ -288,7 +288,7 @@ fn generate_runtime_api_base_structures(impls: &[ItemImpl]) -> Result<TokenStrea
 			fn runtime_version_at(
 				&self,
 				at: &#block_id
-			) -> #crate_::error::Result<#crate_::runtime_api::RuntimeVersion> {
+			) -> std::result::Result<#crate_::RuntimeVersion, C::Error> {
 				self.call.runtime_version_at(at)
 			}

@@ -296,7 +296,7 @@ fn generate_runtime_api_base_structures(impls: &[ItemImpl]) -> Result<TokenStrea
 				self.recorder = Some(Default::default());
 			}

-			fn extract_proof(&mut self) -> Option<#crate_::runtime_api::StorageProof> {
+			fn extract_proof(&mut self) -> Option<#crate_::StorageProof> {
 				self.recorder
 					.take()
 					.map(|recorder| {
@@ -306,22 +306,22 @@ fn generate_runtime_api_base_structures(impls: &[ItemImpl]) -> Result<TokenStrea
 							.into_iter()
 							.map(|record| record.data)
 							.collect();
-						#crate_::runtime_api::StorageProof::new(trie_nodes)
+						#crate_::StorageProof::new(trie_nodes)
 					})
 			}
 		}

 		#[cfg(any(feature = "std", test))]
-		impl<C: #crate_::runtime_api::CallRuntimeAt<#block> + 'static>
-			#crate_::runtime_api::ConstructRuntimeApi<#block, C> for RuntimeApi
+		impl<C: #crate_::CallRuntimeAt<#block> + 'static> #crate_::ConstructRuntimeApi<#block, C>
+			for RuntimeApi
 		{
 			type RuntimeApi = RuntimeApiImpl<C>;

 			fn construct_runtime_api<'a>(
 				call: &'a C,
-			) -> #crate_::runtime_api::ApiRef<'a, Self::RuntimeApi> {
+			) -> #crate_::ApiRef<'a, Self::RuntimeApi> {
 				RuntimeApiImpl {
-					call: unsafe { ::std::mem::transmute(call) },
+					call: unsafe { std::mem::transmute(call) },
 					commit_on_success: true.into(),
 					initialized_block: None.into(),
 					changes: Default::default(),
@@ -331,29 +331,28 @@ fn generate_runtime_api_base_structures(impls: &[ItemImpl]) -> Result<TokenStrea
 		}

 		#[cfg(any(feature = "std", test))]
-		impl<C: #crate_::runtime_api::CallRuntimeAt<#block>> RuntimeApiImpl<C> {
+		impl<C: #crate_::CallRuntimeAt<#block>> RuntimeApiImpl<C> {
 			fn call_api_at<
-				R: #crate_::runtime_api::Encode + #crate_::runtime_api::Decode + PartialEq,
+				R: #crate_::Encode + #crate_::Decode + PartialEq,
 				F: FnOnce(
 					&C,
 					&Self,
-					&std::cell::RefCell<#crate_::runtime_api::OverlayedChanges>,
-					&std::cell::RefCell<Option<#crate_::runtime_api::BlockId<#block>>>,
-					&Option<std::rc::Rc<std::cell::RefCell<#crate_::runtime_api::ProofRecorder<#block>>>>,
-				) -> #crate_::error::Result<#crate_::runtime_api::NativeOrEncoded<R>>,
+					&std::cell::RefCell<#crate_::OverlayedChanges>,
+					&std::cell::RefCell<Option<#crate_::BlockId<#block>>>,
+					&Option<std::rc::Rc<std::cell::RefCell<#crate_::ProofRecorder<#block>>>>,
+				) -> std::result::Result<#crate_::NativeOrEncoded<R>, E>,
+				E,
 			>(
 				&self,
 				call_api_at: F,
-			) -> #crate_::error::Result<#crate_::runtime_api::NativeOrEncoded<R>> {
-				let res = unsafe {
-					call_api_at(
-						&self.call,
-						self,
-						&self.changes,
-						&self.initialized_block,
-						&self.recorder,
-					)
-				};
+			) -> std::result::Result<#crate_::NativeOrEncoded<R>, E> {
+				let res = call_api_at(
+					&self.call,
+					self,
+					&self.changes,
+					&self.initialized_block,
+					&self.recorder,
+				);

 				self.commit_on_ok(&res);
 				res
@@ -475,7 +474,7 @@ impl<'a> Fold for ApiRuntimeImplToApiRuntimeApiImpl<'a> {
 			input.sig.inputs = parse_quote! {
 				&self,
 				at: &#block_id,
-				context: #crate_::runtime_api::ExecutionContext,
+				context: #crate_::ExecutionContext,
 				params: Option<( #( #param_types ),* )>,
 				params_encoded: Vec<u8>,
 			};
@@ -488,7 +487,7 @@ impl<'a> Fold for ApiRuntimeImplToApiRuntimeApiImpl<'a> {

 			// Generate the correct return type.
 			input.sig.output = parse_quote!(
-				-> #crate_::error::Result<#crate_::runtime_api::NativeOrEncoded<#ret_type>>
+				-> std::result::Result<#crate_::NativeOrEncoded<#ret_type>, RuntimeApiImplCall::Error>
 			);

 			// Generate the new method implementation that calls into the runtime.
@@ -535,7 +534,7 @@ impl<'a> Fold for ApiRuntimeImplToApiRuntimeApiImpl<'a> {
 		let crate_ = generate_crate_access(HIDDEN_INCLUDES_ID);
 		let block = self.node_block;
 		input.generics.params.push(
-			parse_quote!( RuntimeApiImplCall: #crate_::runtime_api::CallRuntimeAt<#block> + 'static )
+			parse_quote!( RuntimeApiImplCall: #crate_::CallRuntimeAt<#block> + 'static )
 		);

 		// The implementation for the `RuntimeApiImpl` is only required when compiling with
@@ -621,8 +620,7 @@ fn generate_runtime_api_versions(impls: &[ItemImpl]) -> Result<TokenStream> {
 	let c = generate_crate_access(HIDDEN_INCLUDES_ID);

 	Ok(quote!(
-		const RUNTIME_API_VERSIONS: #c::runtime_api::ApisVec =
-			#c::runtime_api::create_apis_vec!([ #( #result ),* ]);
+		const RUNTIME_API_VERSIONS: #c::ApisVec = #c::create_apis_vec!([ #( #result ),* ]);
 	))
 }

@@ -44,14 +44,7 @@ mod utils;
 /// # Example
 ///
 /// ```rust
-/// #[macro_use]
-/// extern crate client;
-/// extern crate sr_version as version;
-///
-/// use version::create_runtime_str;
-/// # extern crate test_client;
-/// # extern crate sr_primitives;
-/// # extern crate primitives;
+/// use sr_version::create_runtime_str;
 /// #
 /// # use sr_primitives::traits::GetNodeBlockType;
 /// # use test_client::runtime::{Block, Header};
@@ -63,7 +56,7 @@ mod utils;
 /// #     type NodeBlock = Block;
 /// # }
 /// #
-/// # decl_runtime_apis! {
+/// # sr_api::decl_runtime_apis! {
 /// #     /// Declare the api trait.
 /// #     pub trait Balance {
 /// #         /// Get the balance.
@@ -77,9 +70,9 @@ mod utils;
 /// # }
 ///
 /// /// All runtime api implementations need to be done in one call of the macro!
-/// impl_runtime_apis! {
-/// #   impl client::runtime_api::Core<Block> for Runtime {
-/// #       fn version() -> client::runtime_api::RuntimeVersion {
+/// sr_api::impl_runtime_apis! {
+/// #   impl sr_api::Core<Block> for Runtime {
+/// #       fn version() -> sr_version::RuntimeVersion {
 /// #           unimplemented!()
 /// #       }
 /// #       fn execute_block(_block: Block) {}
@@ -103,7 +96,7 @@ mod utils;
 /// }
 ///
 /// /// Runtime version. This needs to be declared for each runtime.
-/// pub const VERSION: version::RuntimeVersion = version::RuntimeVersion {
+/// pub const VERSION: sr_version::RuntimeVersion = sr_version::RuntimeVersion {
 ///     spec_name: create_runtime_str!("node"),
 ///     impl_name: create_runtime_str!("test-node"),
 ///     authoring_version: 1,
@@ -134,10 +127,7 @@ pub fn impl_runtime_apis(input: TokenStream) -> TokenStream {
 /// # Example
 ///
 /// ```rust
-/// #[macro_use]
-/// extern crate client;
-///
-/// decl_runtime_apis! {
+/// sr_api::decl_runtime_apis! {
 ///     /// Declare the api trait.
 ///     pub trait Balance {
 ///         /// Get the balance.
@@ -169,10 +159,7 @@ pub fn impl_runtime_apis(input: TokenStream) -> TokenStream {
 /// spec version!). Such a method also does not need to be implemented in the runtime.
 ///
 /// ```rust
-/// #[macro_use]
-/// extern crate client;
-///
-/// decl_runtime_apis! {
+/// sr_api::decl_runtime_apis! {
 ///     /// Declare the api trait.
 ///     #[api_version(2)]
 ///     pub trait Balance {
@@ -37,17 +37,17 @@ fn generate_hidden_includes_mod_name(unique_id: &'static str) -> Ident {

 /// Generates the hidden includes that are required to make the macro independent from its scope.
 pub fn generate_hidden_includes(unique_id: &'static str) -> TokenStream {
-	if env::var("CARGO_PKG_NAME").unwrap() == "substrate-client" {
+	if env::var("CARGO_PKG_NAME").unwrap() == "sr-api" {
 		TokenStream::new()
 	} else {
 		let mod_name = generate_hidden_includes_mod_name(unique_id);
-		match crate_name("substrate-client") {
+		match crate_name("sr-api") {
 			Ok(client_name) => {
 				let client_name = Ident::new(&client_name, Span::call_site());
 				quote!(
 					#[doc(hidden)]
 					mod #mod_name {
-						pub extern crate #client_name as sr_api_client;
+						pub extern crate #client_name as sr_api;
 					}
 				)
 			},
@@ -62,11 +62,11 @@ pub fn generate_hidden_includes(unique_id: &'static str) -> TokenStream {

 /// Generates the access to the `substrate_client` crate.
 pub fn generate_crate_access(unique_id: &'static str) -> TokenStream {
-	if env::var("CARGO_PKG_NAME").unwrap() == "substrate-client" {
+	if env::var("CARGO_PKG_NAME").unwrap() == "sr-api" {
 		quote!( crate )
 	} else {
 		let mod_name = generate_hidden_includes_mod_name(unique_id);
-		quote!( self::#mod_name::sr_api_client )
+		quote!( self::#mod_name::sr_api )
 	}.into()
 }

@@ -102,7 +102,6 @@ pub fn replace_wild_card_parameter_names(input: &mut Signature) {
 pub fn fold_fn_decl_for_client_side(
 	input: &mut Signature,
 	block_id: &TokenStream,
-	crate_: &TokenStream,
 ) {
 	replace_wild_card_parameter_names(input);

@@ -113,7 +112,7 @@ pub fn fold_fn_decl_for_client_side(
 	// Wrap the output in a `Result`
 	input.output = {
 		let ty = return_type_extract_type(&input.output);
-		parse_quote!( -> std::result::Result<#ty, #crate_::error::Error> )
+		parse_quote!( -> std::result::Result<#ty, Self::Error> )
 	};
 }

@@ -0,0 +1,206 @@
+// Copyright 2019 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Substrate is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Substrate runtime api
+//!
+//! The Substrate runtime api is the crucial interface between the node and the runtime.
+//! Every call that goes into the runtime is done with a runtime api. The runtime apis are not fixed.
+//! Every Substrate user can define its own apis with
+//! [`decl_runtime_apis`](macro.decl_runtime_apis.html) and implement them in
+//! the runtime with [`impl_runtime_apis`](macro.impl_runtime_apis.html).
+//!
+//! Every Substrate runtime needs to implement the [`Core`] runtime api. This api provides the basic
+//! functionality that every runtime needs to export.
+//!
+//! Besides the macros and the [`Core`] runtime api, this crates provides the [`Metadata`] runtime
+//! api, the [`ApiExt`] trait, the [`CallRuntimeAt`] trait and the [`ConstructRuntimeApi`] trait.
+
+#![cfg_attr(not(feature = "std"), no_std)]
+
+#[doc(hidden)]
+#[cfg(feature = "std")]
+pub use state_machine::{OverlayedChanges, StorageProof};
+#[doc(hidden)]
+#[cfg(feature = "std")]
+pub use primitives::NativeOrEncoded;
+#[doc(hidden)]
+#[cfg(not(feature = "std"))]
+pub use primitives::to_substrate_wasm_fn_return_value;
+#[doc(hidden)]
+pub use sr_primitives::{
+	traits::{
+		Block as BlockT, GetNodeBlockType, GetRuntimeBlockType,
+		Header as HeaderT, ApiRef, RuntimeApiInfo, Hash as HashT,
+	},
+	generic::BlockId, transaction_validity::TransactionValidity,
+};
+#[doc(hidden)]
+pub use primitives::{offchain, ExecutionContext};
+#[doc(hidden)]
+pub use sr_version::{ApiId, RuntimeVersion, ApisVec, create_apis_vec};
+#[doc(hidden)]
+pub use rstd::{slice, mem};
+#[cfg(feature = "std")]
+use rstd::result;
+#[doc(hidden)]
+pub use codec::{Encode, Decode};
+use primitives::OpaqueMetadata;
+#[cfg(feature = "std")]
+use std::{panic::UnwindSafe, cell::RefCell, rc::Rc};
+#[cfg(feature = "std")]
+use primitives::Hasher as HasherT;
+
+pub use sr_api_proc_macro::{decl_runtime_apis, impl_runtime_apis};
+
+#[cfg(feature = "std")]
+/// A type that records all accessed trie nodes and generates a proof out of it.
+pub type ProofRecorder<B> = state_machine::ProofRecorder<
+	<<<<B as BlockT>::Header as HeaderT>::Hashing as HashT>::Hasher as HasherT>::Out
+>;
+
+/// Something that can be constructed to a runtime api.
+#[cfg(feature = "std")]
+pub trait ConstructRuntimeApi<Block: BlockT, C: CallRuntimeAt<Block>> {
+	/// The actual runtime api that will be constructed.
+	type RuntimeApi;
+
+	/// Construct an instance of the runtime api.
+	fn construct_runtime_api<'a>(call: &'a C) -> ApiRef<'a, Self::RuntimeApi>;
+}
+
+/// An extension for the `RuntimeApi`.
+#[cfg(feature = "std")]
+pub trait ApiExt<Block: BlockT> {
+	/// Error type used by the interface.
+	type Error: std::fmt::Debug + From<String>;
+
+	/// The given closure will be called with api instance. Inside the closure any api call is
+	/// allowed. After doing the api call, the closure is allowed to map the `Result` to a
+	/// different `Result` type. This can be important, as the internal data structure that keeps
+	/// track of modifications to the storage, discards changes when the `Result` is an `Err`.
+	/// On `Ok`, the structure commits the changes to an internal buffer.
+	fn map_api_result<F: FnOnce(&Self) -> result::Result<R, E>, R, E>(
+		&self,
+		map_call: F
+	) -> result::Result<R, E> where Self: Sized;
+
+	/// Checks if the given api is implemented and versions match.
+	fn has_api<A: RuntimeApiInfo + ?Sized>(
+		&self,
+		at: &BlockId<Block>
+	) -> Result<bool, Self::Error> where Self: Sized {
+		self.runtime_version_at(at).map(|v| v.has_api::<A>())
+	}
+
+	/// Check if the given api is implemented and the version passes a predicate.
+	fn has_api_with<A: RuntimeApiInfo + ?Sized, P: Fn(u32) -> bool>(
+		&self,
+		at: &BlockId<Block>,
+		pred: P,
+	) -> Result<bool, Self::Error> where Self: Sized {
+		self.runtime_version_at(at).map(|v| v.has_api_with::<A, _>(pred))
+	}
+
+	/// Returns the runtime version at the given block id.
+	fn runtime_version_at(&self, at: &BlockId<Block>) -> Result<RuntimeVersion, Self::Error>;
+
+	/// Start recording all accessed trie nodes for generating proofs.
+	fn record_proof(&mut self);
+
+	/// Extract the recorded proof.
+	/// This stops the proof recording.
+	fn extract_proof(&mut self) -> Option<StorageProof>;
+}
+
+/// Before calling any runtime api function, the runtime need to be initialized
+/// at the requested block. However, some functions like `execute_block` or
+/// `initialize_block` itself don't require to have the runtime initialized
+/// at the requested block.
+///
+/// `call_api_at` is instructed by this enum to do the initialization or to skip
+/// it.
+#[cfg(feature = "std")]
+#[derive(Clone, Copy)]
+pub enum InitializeBlock<'a, Block: BlockT> {
+	/// Skip initializing the runtime for a given block.
+	///
+	/// This is used by functions who do the initialization by themselves or don't require it.
+	Skip,
+	/// Initialize the runtime for a given block.
+	///
+	/// If the stored `BlockId` is `Some(_)`, the runtime is currently initialized at this block.
+	Do(&'a RefCell<Option<BlockId<Block>>>),
+}
+
+/// Something that can call into the runtime at a given block.
+#[cfg(feature = "std")]
+pub trait CallRuntimeAt<Block: BlockT> {
+	/// Error type used by the interface.
+	type Error: std::fmt::Debug + From<String>;
+
+	/// Calls the given api function with the given encoded arguments at the given block and returns
+	/// the encoded result.
+	fn call_api_at<
+		'a,
+		R: Encode + Decode + PartialEq,
+		NC: FnOnce() -> result::Result<R, String> + UnwindSafe,
+		C: Core<Block, Error = Self::Error>,
+	>(
+		&self,
+		core_api: &C,
+		at: &BlockId<Block>,
+		function: &'static str,
+		args: Vec<u8>,
+		changes: &RefCell<OverlayedChanges>,
+		initialize_block: InitializeBlock<'a, Block>,
+		native_call: Option<NC>,
+		context: ExecutionContext,
+		recorder: &Option<Rc<RefCell<ProofRecorder<Block>>>>,
+	) -> Result<NativeOrEncoded<R>, Self::Error>;
+
+	/// Returns the runtime version at the given block.
+	fn runtime_version_at(&self, at: &BlockId<Block>) -> Result<RuntimeVersion, Self::Error>;
+}
+
+/// Extracts the `Api::Error` for a type that provides a runtime api.
+#[cfg(feature = "std")]
+pub type ApiErrorFor<T, Block> = <
+	<T as sr_primitives::traits::ProvideRuntimeApi>::Api as ApiExt<Block>
+>::Error;
+
+decl_runtime_apis! {
+	/// The `Core` runtime api that every Substrate runtime needs to implement.
+	#[core_trait]
+	#[api_version(2)]
+	pub trait Core {
+		/// Returns the version of the runtime.
+		fn version() -> RuntimeVersion;
+		/// Execute the given block.
+		#[skip_initialize_block]
+		fn execute_block(block: Block);
+		/// Initialize a block with the given header.
+		#[renamed("initialise_block", 2)]
+		#[skip_initialize_block]
+		#[initialize_block]
+		fn initialize_block(header: &<Block as BlockT>::Header);
+	}
+
+	/// The `Metadata` api trait that returns metadata for the runtime.
+	pub trait Metadata {
+		/// Returns the metadata of a runtime.
+		fn metadata() -> OpaqueMetadata;
+	}
+}
@@ -0,0 +1,21 @@
+[package]
+name = "sr-api-test"
+version = "2.0.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2018"
+
+[dependencies]
+sr-api = { path = "../" }
+test-client = { package = "substrate-test-runtime-client", path = "../../test-runtime/client" }
+sr-version = { path = "../../sr-version" }
+sr-primitives = { path = "../../sr-primitives" }
+consensus_common = { package = "substrate-consensus-common", path = "../../consensus/common" }
+codec = { package = "parity-scale-codec", version = "1.0.0" }
+state-machine = { package = "substrate-state-machine", path = "../../state-machine" }
+trybuild = "1.0.17"
+rustversion = "1.0.0"
+
+# We only need this to generate the correct code.
+[features]
+default = [ "std" ]
+std = []
@@ -14,11 +14,11 @@
 // You should have received a copy of the GNU General Public License
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.

-use sr_primitives::traits::{GetNodeBlockType, Block as BlockT};
-use sr_primitives::generic::BlockId;
-use client::runtime_api::{self, RuntimeApiInfo};
-use client::{error::Result, decl_runtime_apis, impl_runtime_apis};
-use test_client::runtime::Block;
+use sr_api::{RuntimeApiInfo, decl_runtime_apis, impl_runtime_apis};
+
+use sr_primitives::{traits::{GetNodeBlockType, Block as BlockT}, generic::BlockId};
+
+use test_client::{client::error::Result, runtime::Block};

 /// The declaration of the `Runtime` type and the implementation of the `GetNodeBlockType`
 /// trait are done by the `construct_runtime!` macro in a real runtime.
@@ -67,8 +67,8 @@ impl_runtime_apis! {
 		fn same_name() {}
 	}

-	impl runtime_api::Core<Block> for Runtime {
-		fn version() -> runtime_api::RuntimeVersion {
+	impl sr_api::Core<Block> for Runtime {
+		fn version() -> sr_version::RuntimeVersion {
 			unimplemented!()
 		}
 		fn execute_block(_: Block) {
@@ -80,7 +80,9 @@ impl_runtime_apis! {
 	}
 }

-type TestClient = client::Client<test_client::Backend, test_client::Executor, Block, RuntimeApi>;
+type TestClient = test_client::client::Client<
+	test_client::Backend, test_client::Executor, Block, RuntimeApi
+>;

 #[test]
 fn test_client_side_function_signature() {
@@ -98,15 +100,19 @@ fn test_client_side_function_signature() {

 #[test]
 fn check_runtime_api_info() {
-	assert_eq!(&Api::<Block>::ID, &runtime_decl_for_Api::ID);
-	assert_eq!(Api::<Block>::VERSION, runtime_decl_for_Api::VERSION);
-	assert_eq!(Api::<Block>::VERSION, 1);
+	assert_eq!(&Api::<Block, Error = ()>::ID, &runtime_decl_for_Api::ID);
+	assert_eq!(Api::<Block, Error = ()>::VERSION, runtime_decl_for_Api::VERSION);
+	assert_eq!(Api::<Block, Error = ()>::VERSION, 1);

 	assert_eq!(
-		ApiWithCustomVersion::<Block>::VERSION, runtime_decl_for_ApiWithCustomVersion::VERSION
+		ApiWithCustomVersion::<Block, Error = ()>::VERSION,
+		runtime_decl_for_ApiWithCustomVersion::VERSION,
 	);
-	assert_eq!(&ApiWithCustomVersion::<Block>::ID, &runtime_decl_for_ApiWithCustomVersion::ID);
-	assert_eq!(ApiWithCustomVersion::<Block>::VERSION, 2);
+	assert_eq!(
+		&ApiWithCustomVersion::<Block, Error = ()>::ID,
+		&runtime_decl_for_ApiWithCustomVersion::ID,
+	);
+	assert_eq!(ApiWithCustomVersion::<Block, Error = ()>::VERSION, 2);
 }

 fn check_runtime_api_versions_contains<T: RuntimeApiInfo + ?Sized>() {
@@ -115,7 +121,7 @@ fn check_runtime_api_versions_contains<T: RuntimeApiInfo + ?Sized>() {

 #[test]
 fn check_runtime_api_versions() {
-	check_runtime_api_versions_contains::<dyn Api<Block>>();
-	check_runtime_api_versions_contains::<dyn ApiWithCustomVersion<Block>>();
-	check_runtime_api_versions_contains::<dyn runtime_api::Core<Block>>();
+	check_runtime_api_versions_contains::<dyn Api<Block, Error = ()>>();
+	check_runtime_api_versions_contains::<dyn ApiWithCustomVersion<Block, Error = ()>>();
+	check_runtime_api_versions_contains::<dyn sr_api::Core<Block, Error = ()>>();
 }
@@ -1,6 +1,4 @@
-use client::decl_runtime_apis;
-
-decl_runtime_apis! {
+sr_api::decl_runtime_apis! {
 	pub trait Api {
 		fn test(&self);
 	}
@@ -0,0 +1,5 @@
+error: `self` as argument not supported.
+ --> $DIR/adding_self_parameter.rs:3:11
+  |
+3 |         fn test(&self);
+  |                 ^
@@ -1,6 +1,5 @@
 use sr_primitives::traits::GetNodeBlockType;
 use test_client::runtime::Block;
-use client::decl_runtime_apis;

 /// The declaration of the `Runtime` type and the implementation of the `GetNodeBlockType`
 /// trait are done by the `construct_runtime!` macro in a real runtime.
@@ -9,7 +8,7 @@ impl GetNodeBlockType for Runtime {
 	type NodeBlock = Block;
 }

-decl_runtime_apis! {
+sr_api::decl_runtime_apis! {
 	pub trait Api {
 		#[changed_in(2)]
 		fn test(data: u64);
@@ -1,5 +1,5 @@
 error: `changed_in` version can not be greater than the `api_version`
-  --> $DIR/changed_in_unknown_version.rs:15:3
+  --> $DIR/changed_in_unknown_version.rs:14:3
   |
-15 |         fn test(data: u64);
+14 |         fn test(data: u64);
   |         ^^
@@ -1,7 +1,6 @@
 use sr_primitives::traits::Block as BlockT;
-use client::decl_runtime_apis;

-decl_runtime_apis! {
+sr_api::decl_runtime_apis! {
 	pub trait Api<Block: BlockT> {
 		fn test();
 	}
@@ -1,13 +1,13 @@
 error: `Block: BlockT` generic parameter will be added automatically by the `decl_runtime_apis!` macro!
- --> $DIR/declaring_old_block.rs:5:16
+ --> $DIR/declaring_old_block.rs:4:16
  |
-5 |     pub trait Api<Block: BlockT> {
+4 |     pub trait Api<Block: BlockT> {
  |                   ^^^^^

 error: `Block: BlockT` generic parameter will be added automatically by the `decl_runtime_apis!` macro! If you try to use a different trait than the substrate `Block` trait, please rename it locally.
- --> $DIR/declaring_old_block.rs:5:23
+ --> $DIR/declaring_old_block.rs:4:23
  |
-5 |     pub trait Api<Block: BlockT> {
+4 |     pub trait Api<Block: BlockT> {
  |                          ^^^^^^

 warning: unused import: `sr_primitives::traits::Block as BlockT`
@@ -1,7 +1,6 @@
 use sr_primitives::traits::Block as BlockT;
-use client::decl_runtime_apis;

-decl_runtime_apis! {
+sr_api::decl_runtime_apis! {
 	pub trait Api<B: BlockT> {
 		fn test();
 	}
@@ -1,7 +1,7 @@
 error: `Block: BlockT` generic parameter will be added automatically by the `decl_runtime_apis!` macro! If you try to use a different trait than the substrate `Block` trait, please rename it locally.
- --> $DIR/declaring_own_block_with_different_name.rs:5:19
+ --> $DIR/declaring_own_block_with_different_name.rs:4:19
  |
-5 |     pub trait Api<B: BlockT> {
+4 |     pub trait Api<B: BlockT> {
  |                      ^^^^^^

 warning: unused import: `sr_primitives::traits::Block as BlockT`
@@ -1,6 +1,5 @@
 use sr_primitives::traits::GetNodeBlockType;
 use test_client::runtime::Block;
-use client::{decl_runtime_apis, impl_runtime_apis};

 /// The declaration of the `Runtime` type and the implementation of the `GetNodeBlockType`
 /// trait are done by the `construct_runtime!` macro in a real runtime.
@@ -9,12 +8,12 @@ impl GetNodeBlockType for Runtime {
 	type NodeBlock = Block;
 }

-decl_runtime_apis! {
+sr_api::decl_runtime_apis! {
 	pub trait Api {
 		fn test(data: u64);
 	}
 }

-impl_runtime_apis! {}
+sr_api::impl_runtime_apis! {}

 fn main() {}
@@ -0,0 +1,5 @@
+error: No api implementation given!
+  --> $DIR/empty_impl_runtime_apis_call.rs:17:1
+   |
+17 | sr_api::impl_runtime_apis! {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ in this macro invocation
@@ -1,6 +1,5 @@
 use sr_primitives::traits::{GetNodeBlockType, Block as BlockT};
 use test_client::runtime::Block;
-use client::{decl_runtime_apis, impl_runtime_apis, runtime_api};

 /// The declaration of the `Runtime` type and the implementation of the `GetNodeBlockType`
 /// trait are done by the `construct_runtime!` macro in a real runtime.
@@ -9,18 +8,18 @@ impl GetNodeBlockType for Runtime {
 	type NodeBlock = Block;
 }

-decl_runtime_apis! {
+sr_api::decl_runtime_apis! {
 	pub trait Api {
 		fn test(data: u64);
 	}
 }

-impl_runtime_apis! {
+sr_api::impl_runtime_apis! {
 	impl self::Api<Block> for Runtime {
 		fn test(data: String) {}
 	}

-	impl runtime_api::Core<Block> for Runtime {
+	impl sr_api::Core<Block> for Runtime {
 		fn version() -> runtime_api::RuntimeVersion {
 			unimplemented!()
 		}
@@ -0,0 +1,70 @@
+error[E0433]: failed to resolve: use of undeclared type or module `runtime_api`
+  --> $DIR/impl_incorrect_method_signature.rs:23:19
+   |
+23 |         fn version() -> runtime_api::RuntimeVersion {
+   |                         ^^^^^^^^^^^ use of undeclared type or module `runtime_api`
+
+error[E0053]: method `test` has an incompatible type for trait
+  --> $DIR/impl_incorrect_method_signature.rs:19:17
+   |
+13 |         fn test(data: u64);
+   |                       --- type in trait
+...
+19 |         fn test(data: String) {}
+   |                       ^^^^^^ expected u64, found struct `std::string::String`
+   |
+   = note: expected type `fn(u64)`
+              found type `fn(std::string::String)`
+
+error[E0053]: method `Api_test_runtime_api_impl` has an incompatible type for trait
+  --> $DIR/impl_incorrect_method_signature.rs:17:1
+   |
+11 | / sr_api::decl_runtime_apis! {
+12 | |     pub trait Api {
+13 | |         fn test(data: u64);
+14 | |     }
+15 | | }
+   | |_- type in trait
+16 | 
+17 |   sr_api::impl_runtime_apis! {
+   |   -^^^^^^^^^^^^^^^^^^^^^^^^^
+   |   |
+   |  _expected u64, found struct `std::string::String`
+   | |
+18 | |     impl self::Api<Block> for Runtime {
+19 | |         fn test(data: String) {}
+20 | |     }
+...  |
+32 | |     }
+33 | | }
+   | |_- in this macro invocation
+   |
+   = note: expected type `fn(&RuntimeApiImpl<RuntimeApiImplCall>, &sr_api_hidden_includes_DECL_RUNTIME_APIS::sr_api::BlockId<sr_primitives::generic::block::Block<sr_primitives::generic::header::Header<u64, sr_primitives::traits::BlakeTwo256>, substrate_test_runtime::Extrinsic>>, sr_api_hidden_includes_DECL_RUNTIME_APIS::sr_api::ExecutionContext, std::option::Option<u64>, std::vec::Vec<u8>) -> std::result::Result<sr_api_hidden_includes_DECL_RUNTIME_APIS::sr_api::NativeOrEncoded<()>, <RuntimeApiImplCall as sr_api_hidden_includes_DECL_RUNTIME_APIS::sr_api::CallRuntimeAt<sr_primitives::generic::block::Block<sr_primitives::generic::header::Header<u64, sr_primitives::traits::BlakeTwo256>, substrate_test_runtime::Extrinsic>>>::Error>`
+              found type `fn(&RuntimeApiImpl<RuntimeApiImplCall>, &sr_api_hidden_includes_DECL_RUNTIME_APIS::sr_api::BlockId<sr_primitives::generic::block::Block<sr_primitives::generic::header::Header<u64, sr_primitives::traits::BlakeTwo256>, substrate_test_runtime::Extrinsic>>, sr_api_hidden_includes_DECL_RUNTIME_APIS::sr_api::ExecutionContext, std::option::Option<std::string::String>, std::vec::Vec<u8>) -> std::result::Result<sr_api_hidden_includes_DECL_RUNTIME_APIS::sr_api::NativeOrEncoded<()>, <RuntimeApiImplCall as sr_api_hidden_includes_DECL_RUNTIME_APIS::sr_api::CallRuntimeAt<sr_primitives::generic::block::Block<sr_primitives::generic::header::Header<u64, sr_primitives::traits::BlakeTwo256>, substrate_test_runtime::Extrinsic>>>::Error>`
+
+error[E0308]: mismatched types
+  --> $DIR/impl_incorrect_method_signature.rs:17:1
+   |
+17 | / sr_api::impl_runtime_apis! {
+18 | |     impl self::Api<Block> for Runtime {
+19 | |         fn test(data: String) {}
+20 | |     }
+...  |
+32 | |     }
+33 | | }
+   | | ^
+   | | |
+   | |_expected u64, found struct `std::string::String`
+   |   in this macro invocation
+   |
+   = note: expected type `u64`
+              found type `std::string::String`
+
+error[E0308]: mismatched types
+  --> $DIR/impl_incorrect_method_signature.rs:19:11
+   |
+19 |         fn test(data: String) {}
+   |                 ^^^^ expected u64, found struct `std::string::String`
+   |
+   = note: expected type `u64`
+              found type `std::string::String`
@@ -1,6 +1,5 @@
 use sr_primitives::traits::GetNodeBlockType;
 use test_client::runtime::Block;
-use client::{decl_runtime_apis, impl_runtime_apis};

 /// The declaration of the `Runtime` type and the implementation of the `GetNodeBlockType`
 /// trait are done by the `construct_runtime!` macro in a real runtime.
@@ -9,7 +8,7 @@ impl GetNodeBlockType for Runtime {
 	type NodeBlock = Block;
 }

-decl_runtime_apis! {
+sr_api::decl_runtime_apis! {
 	pub trait Api {
 		fn test(data: u64);
 	}
@@ -25,7 +24,7 @@ mod second {
 	}
 }

-impl_runtime_apis! {
+sr_api::impl_runtime_apis! {
 	impl self::Api<Block> for Runtime {
 		fn test(data: u64) {}
 	}
@@ -0,0 +1,77 @@
+error: Two traits with the same name detected! The trait name is used to generate its ID. Please rename one trait at the declaration!
+  --> $DIR/impl_two_traits_with_same_name.rs:32:15
+   |
+32 |     impl second::Api<Block> for Runtime {
+   |                  ^^^
+
+error: cannot find macro `decl_runtime_apis` in this scope
+  --> $DIR/impl_two_traits_with_same_name.rs:20:2
+   |
+20 |     decl_runtime_apis! {
+   |     ^^^^^^^^^^^^^^^^^
+
+error[E0425]: cannot find function `test2_call_api_at` in `second::runtime_decl_for_Api`
+  --> $DIR/impl_two_traits_with_same_name.rs:27:1
+   |
+27 | / sr_api::impl_runtime_apis! {
+28 | |     impl self::Api<Block> for Runtime {
+29 | |         fn test(data: u64) {}
+30 | |     }
+...  |
+34 | |     }
+35 | | }
+   | | ^
+   | | |
+   | |_not found in `second::runtime_decl_for_Api`
+   |   in this macro invocation
+
+error[E0425]: cannot find function `test2_native_call_generator` in `second::runtime_decl_for_Api`
+  --> $DIR/impl_two_traits_with_same_name.rs:27:1
+   |
+27 | / sr_api::impl_runtime_apis! {
+28 | |     impl self::Api<Block> for Runtime {
+29 | |         fn test(data: u64) {}
+30 | |     }
+...  |
+34 | |     }
+35 | | }
+   | | ^
+   | | |
+   | |_not found in `second::runtime_decl_for_Api`
+   |   in this macro invocation
+
+error[E0576]: cannot find method or associated constant `test2` in `second::runtime_decl_for_Api::Api`
+  --> $DIR/impl_two_traits_with_same_name.rs:33:6
+   |
+33 |         fn test2(data: u64) {}
+   |            ^^^^^ not found in `second::runtime_decl_for_Api::Api`
+
+error[E0603]: module `runtime_decl_for_Api` is private
+  --> $DIR/impl_two_traits_with_same_name.rs:27:1
+   |
+27 | / sr_api::impl_runtime_apis! {
+28 | |     impl self::Api<Block> for Runtime {
+29 | |         fn test(data: u64) {}
+30 | |     }
+...  |
+34 | |     }
+35 | | }
+   | |_^
+
+error[E0119]: conflicting implementations of trait `runtime_decl_for_Api::Api<sr_primitives::generic::block::Block<sr_primitives::generic::header::Header<u64, sr_primitives::traits::BlakeTwo256>, substrate_test_runtime::Extrinsic>>` for type `Runtime`:
+  --> $DIR/impl_two_traits_with_same_name.rs:32:2
+   |
+28 |     impl self::Api<Block> for Runtime {
+   |     --------------------------------- first implementation here
+...
+32 |     impl second::Api<Block> for Runtime {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `Runtime`
+
+error[E0119]: conflicting implementations of trait `Api<sr_primitives::generic::block::Block<sr_primitives::generic::header::Header<u64, sr_primitives::traits::BlakeTwo256>, substrate_test_runtime::Extrinsic>>` for type `RuntimeApiImpl<_>`:
+  --> $DIR/impl_two_traits_with_same_name.rs:32:2
+   |
+28 |     impl self::Api<Block> for Runtime {
+   |     --------------------------------- first implementation here
+...
+32 |     impl second::Api<Block> for Runtime {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `RuntimeApiImpl<_>`
@@ -1,6 +1,4 @@
-use client::decl_runtime_apis;
-
-decl_runtime_apis! {
+sr_api::decl_runtime_apis! {
 	#[api_version]
 	pub trait Api {
 		fn test(data: u64);
@@ -1,12 +1,12 @@
 error: can't qualify macro invocation with `pub`
- --> $DIR/invalid_api_version.rs:3:1
+ --> $DIR/invalid_api_version.rs:1:1
  |
-3 | / decl_runtime_apis! {
-4 | |     #[api_version]
-5 | |     pub trait Api {
-6 | |         fn test(data: u64);
-7 | |     }
-8 | | }
+1 | / sr_api::decl_runtime_apis! {
+2 | |     #[api_version]
+3 | |     pub trait Api {
+4 | |         fn test(data: u64);
+5 | |     }
+6 | | }
  | | ^ in this macro invocation
  | |_|
  | 
@@ -14,20 +14,20 @@ error: can't qualify macro invocation with `pub`
  = help: try adjusting the macro to put `pub` inside the invocation

 error: Unexpected `api_version` attribute. The supported format is `api_version(1)`
- --> $DIR/invalid_api_version.rs:3:1
+ --> $DIR/invalid_api_version.rs:1:1
  |
-3 | / decl_runtime_apis! {
-4 | |     #[api_version]
-5 | |     pub trait Api {
-6 | |         fn test(data: u64);
-7 | |     }
-8 | | }
+1 | / sr_api::decl_runtime_apis! {
+2 | |     #[api_version]
+3 | |     pub trait Api {
+4 | |         fn test(data: u64);
+5 | |     }
+6 | | }
  | | ^ in this macro invocation
  | |_|
  | 

 error: Unexpected `api_version` attribute. The supported format is `api_version(1)`
- --> $DIR/invalid_api_version.rs:4:4
+ --> $DIR/invalid_api_version.rs:2:4
  |
-4 |     #[api_version]
+2 |     #[api_version]
  |       ^^^^^^^^^^^
@@ -1,6 +1,4 @@
-use client::decl_runtime_apis;
-
-decl_runtime_apis! {
+sr_api::decl_runtime_apis! {
 	#[api_version("1")]
 	pub trait Api {
 		fn test(data: u64);
@@ -0,0 +1,33 @@
+error: can't qualify macro invocation with `pub`
+ --> $DIR/invalid_api_version_2.rs:1:1
+  |
+1 | / sr_api::decl_runtime_apis! {
+2 | |     #[api_version("1")]
+3 | |     pub trait Api {
+4 | |         fn test(data: u64);
+5 | |     }
+6 | | }
+  | | ^ in this macro invocation
+  | |_|
+  | 
+  |
+  = help: try adjusting the macro to put `pub` inside the invocation
+
+error: Unexpected `api_version` attribute. The supported format is `api_version(1)`
+ --> $DIR/invalid_api_version_2.rs:1:1
+  |
+1 | / sr_api::decl_runtime_apis! {
+2 | |     #[api_version("1")]
+3 | |     pub trait Api {
+4 | |         fn test(data: u64);
+5 | |     }
+6 | | }
+  | | ^ in this macro invocation
+  | |_|
+  | 
+
+error: Unexpected `api_version` attribute. The supported format is `api_version(1)`
+ --> $DIR/invalid_api_version_2.rs:2:4
+  |
+2 |     #[api_version("1")]
+  |       ^^^^^^^^^^^
@@ -1,6 +1,4 @@
-use client::decl_runtime_apis;
-
-decl_runtime_apis! {
+sr_api::decl_runtime_apis! {
 	#[api_version()]
 	pub trait Api {
 		fn test(data: u64);
@@ -0,0 +1,33 @@
+error: can't qualify macro invocation with `pub`
+ --> $DIR/invalid_api_version_3.rs:1:1
+  |
+1 | / sr_api::decl_runtime_apis! {
+2 | |     #[api_version()]
+3 | |     pub trait Api {
+4 | |         fn test(data: u64);
+5 | |     }
+6 | | }
+  | | ^ in this macro invocation
+  | |_|
+  | 
+  |
+  = help: try adjusting the macro to put `pub` inside the invocation
+
+error: Unexpected `api_version` attribute. The supported format is `api_version(1)`
+ --> $DIR/invalid_api_version_3.rs:1:1
+  |
+1 | / sr_api::decl_runtime_apis! {
+2 | |     #[api_version()]
+3 | |     pub trait Api {
+4 | |         fn test(data: u64);
+5 | |     }
+6 | | }
+  | | ^ in this macro invocation
+  | |_|
+  | 
+
+error: Unexpected `api_version` attribute. The supported format is `api_version(1)`
+ --> $DIR/invalid_api_version_3.rs:2:4
+  |
+2 |     #[api_version()]
+  |       ^^^^^^^^^^^
@@ -1,6 +1,5 @@
 use sr_primitives::traits::GetNodeBlockType;
 use test_client::runtime::Block;
-use client::{decl_runtime_apis, impl_runtime_apis};

 /// The declaration of the `Runtime` type and the implementation of the `GetNodeBlockType`
 /// trait are done by the `construct_runtime!` macro in a real runtime.
@@ -9,13 +8,13 @@ impl GetNodeBlockType for Runtime {
 	type NodeBlock = Block;
 }

-decl_runtime_apis! {
+sr_api::decl_runtime_apis! {
 	pub trait Api {
 		fn test(data: u64);
 	}
 }

-impl_runtime_apis! {
+sr_api::impl_runtime_apis! {
 	impl self::Api for Runtime {
 		fn test(data: u64) {
 			unimplemented!()
@@ -0,0 +1,11 @@
+error: Missing `Block` generic parameter.
+  --> $DIR/missing_block_generic_parameter.rs:18:13
+   |
+18 |     impl self::Api for Runtime {
+   |                ^^^
+
+error[E0107]: wrong number of type arguments: expected 1, found 0
+  --> $DIR/missing_block_generic_parameter.rs:18:7
+   |
+18 |     impl self::Api for Runtime {
+   |          ^^^^^^^^^ expected 1 type argument
@@ -1,6 +1,5 @@
 use sr_primitives::traits::GetNodeBlockType;
 use test_client::runtime::Block;
-use client::{decl_runtime_apis, impl_runtime_apis};

 /// The declaration of the `Runtime` type and the implementation of the `GetNodeBlockType`
 /// trait are done by the `construct_runtime!` macro in a real runtime.
@@ -9,13 +8,13 @@ impl GetNodeBlockType for Runtime {
 	type NodeBlock = Block;
 }

-decl_runtime_apis! {
+sr_api::decl_runtime_apis! {
 	pub trait Api {
 		fn test(data: u64);
 	}
 }

-impl_runtime_apis! {
+sr_api::impl_runtime_apis! {
 	impl Api<Block> for Runtime {
 		fn test(data: u64) {
 			unimplemented!()
--- a/Show More
+++ b/Show More