Runtime logging. (#3821)

* Implement Printable for tuples.

* Add debugging function.

* Add debug 1.

* Implement  for everything.

* RuntimeDebug derive.

* Introduce RuntimeDebug.

* Add some dummy logging.

* Replace RuntimeDebug with Debug.

* Revert "Replace RuntimeDebug with Debug."

This reverts commit bc47070a8cb30241b2b590b2fa29fd195088162f.

* Working on Debug for all.

* Fix bounds.

* Add debug utils.

* Implement runtime logging.

* Add some docs and clean up.

* Clean up derives.

* Fix custom derive impl.

* Bump runtime.

* Fix long lines.

* Fix doc test.

* Use CARGO_CFG_STD.

* Revert "Use CARGO_CFG_STD."

This reverts commit ea429566de18ed0fa052571b359eb9826a64a9f4.

* Use parse_macro_input

* Update lockfile.

* Apply review suggestions.

* Remove stray re-export.

* Add no-std impl.

* Update lockfile.

substrate/core/primitives/debug-derive/tests/tests.rs

@@ -0,0 +1,63 @@
+// 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/>.
+
+use substrate_debug_derive::RuntimeDebug;
+
+#[derive(RuntimeDebug)]
+struct Unnamed(u64, String);
+
+#[derive(RuntimeDebug)]
+struct Named {
+	a: u64,
+	b: String,
+}
+
+#[derive(RuntimeDebug)]
+enum EnumLongName<A> {
+	A,
+	B(A, String),
+	VariantLongName {
+		a: A,
+		b: String,
+	},
+}
+
+
+#[test]
+fn should_display_proper_debug() {
+	use self::EnumLongName as Enum;
+
+	assert_eq!(
+		format!("{:?}", Unnamed(1, "abc".into())),
+		"Unnamed(1, \"abc\")"
+	);
+	assert_eq!(
+		format!("{:?}", Named { a: 1, b: "abc".into() }),
+		"Named { a: 1, b: \"abc\" }"
+	);
+	assert_eq!(
+		format!("{:?}", Enum::<u64>::A),
+		"EnumLongName::A"
+	);
+	assert_eq!(
+		format!("{:?}", Enum::B(1, "abc".into())),
+		"EnumLongName::B(1, \"abc\")"
+	);
+	assert_eq!(
+		format!("{:?}", Enum::VariantLongName { a: 1, b: "abc".into() }),
+		"EnumLongName::VariantLongName { a: 1, b: \"abc\" }"
+	);
+}