Weight annotation. (#3157)

* Make extrinsics extensible.

Also Remove old extrinsic types.

* Rest of mockup. Add tips.

* Fix some build issues

* Runtiem builds :)

* Substrate builds.

* Fix a doc test

* Compact encoding

* Extract out the era logic into an extension

* Weight Check signed extension. (#3115)

* Weight signed extension.

* Revert a bit + test for check era.

* Update Cargo.toml

* Update node/cli/src/factory_impl.rs

* Update node/executor/src/lib.rs

* Update node/executor/src/lib.rs

* Don't use len for weight - use data.

* Operational Transaction; second attempt (#3138)

* working poc added.

* some fixes.

* Update doc.

* Fix all tests + final logic.

* more refactoring.

* nits.

* System block limit in bytes.

* Silent the storage macro warnings.

* More logic more tests.

* Fix import.

* Refactor names.

* Fix build.

* Update srml/balances/src/lib.rs

* Final refactor.

* Bump transaction version

* Fix weight mult test.

* Fix more tests and improve doc.

* Bump.

* Make some tests work again.

* Fix subkey.

* Remove todos + bump.

* First draft of annotating weights.

* Refactor weight to u64.

* More refactoring and tests.

* New convert for weight to fee

* more tests.

* remove merge redundancy.

* Fix system test.

* Bring back subkey stuff.

* a few stress tests.

* fix some of the grumbles.

* Final nits.

* Update srml/system/src/lib.rs

Co-Authored-By: DemiMarie-parity <48690212+DemiMarie-parity@users.noreply.github.com>

* Scale weights by 1000.

* Bump.

* Fix decl_storage test.

substrate/core/sr-primitives/src/lib.rs

@@ -182,11 +182,16 @@ impl Permill {
 	/// Everything.
 	pub fn one() -> Self { Self(1_000_000) }
 
+	/// create a new raw instance. This can be called at compile time.
+	pub const fn from_const_parts(parts: u32) -> Self {
+		Self([parts, 1_000_000][(parts > 1_000_000) as usize])
+	}
+
 	/// From an explicitly defined number of parts per maximum of the type.
-	pub fn from_parts(x: u32) -> Self { Self(x.min(1_000_000)) }
+	pub fn from_parts(parts: u32) -> Self { Self::from_const_parts(parts) }
 
 	/// Converts from a percent. Equal to `x / 100`.
-	pub fn from_percent(x: u32) -> Self { Self(x.min(100) * 10_000) }
+	pub const fn from_percent(x: u32) -> Self { Self([x, 100][(x > 100) as usize] * 10_000) }
 
 	/// Converts a fraction into `Permill`.
 	#[cfg(feature = "std")]
@@ -286,11 +291,16 @@ impl Perbill {
 	/// Everything.
 	pub fn one() -> Self { Self(1_000_000_000) }
 
+	/// create a new raw instance. This can be called at compile time.
+	pub const fn from_const_parts(parts: u32) -> Self {
+		Self([parts, 1_000_000_000][(parts > 1_000_000_000) as usize])
+	}
+
 	/// From an explicitly defined number of parts per maximum of the type.
-	pub fn from_parts(x: u32) -> Self { Self(x.min(1_000_000_000)) }
+	pub fn from_parts(parts: u32) -> Self { Self::from_const_parts(parts) }
 
 	/// Converts from a percent. Equal to `x / 100`.
-	pub fn from_percent(x: u32) -> Self { Self(x.min(100) * 10_000_000) }
+	pub const fn from_percent(x: u32) -> Self { Self([x, 100][(x > 100) as usize] * 10_000_000) }
 
 	/// Construct new instance where `x` is in millionths. Value equivalent to `x / 1,000,000`.
 	pub fn from_millionths(x: u32) -> Self { Self(x.min(1_000_000) * 1000) }
@@ -411,11 +421,12 @@ impl Fixed64 {
 
 	/// Performs a saturated multiply and accumulate.
 	///
-	/// Returns `n + (self * n)`.
+	/// Returns a saturated `n + (self * n)`.
+	/// TODO: generalize this to any weight type. #3189
 	pub fn saturated_multiply_accumulate(&self, int: u32) -> u32 {
 		let parts = self.0;
-
 		let positive = parts > 0;
+
 		// natural parts might overflow.
 		let natural_parts = self.clone().saturated_into::<u32>();
 		// fractional parts can always fit into u32.
@@ -459,8 +470,8 @@ impl Saturating for Fixed64 {
 	}
 }
 
-/// Note that this is a standard, _potentially-panicking_, implementation. Use `Saturating` trait for
-/// safe addition.
+/// Note that this is a standard, _potentially-panicking_, implementation. Use `Saturating` trait
+/// for safe addition.
 impl ops::Add for Fixed64 {
 	type Output = Self;
 
@@ -469,8 +480,8 @@ impl ops::Add for Fixed64 {
 	}
 }
 
-/// Note that this is a standard, _potentially-panicking_, implementation. Use `Saturating` trait for
-/// safe subtraction.
+/// Note that this is a standard, _potentially-panicking_, implementation. Use `Saturating` trait
+/// for safe subtraction.
 impl ops::Sub for Fixed64 {
 	type Output = Self;