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Use lifetime contravariance to elide more lifetimes in core+alloc+std #59056

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merged 1 commit into from Mar 13, 2019

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scottmcm commented Mar 10, 2019 •
edited

Sample:

-    impl<'a, 'b, A: ?Sized, B: ?Sized> PartialEq<&'b mut B> for &'a mut A where A: PartialEq<B> {
+    impl<A: ?Sized, B: ?Sized> PartialEq<&mut B> for &mut A where A: PartialEq<B> {
         #[inline]
-        fn eq(&self, other: &&'b mut B) -> bool { PartialEq::eq(*self, *other) }
+        fn eq(&self, other: &&mut B) -> bool { PartialEq::eq(*self, *other) }
         #[inline]
-        fn ne(&self, other: &&'b mut B) -> bool { PartialEq::ne(*self, *other) }
+        fn ne(&self, other: &&mut B) -> bool { PartialEq::ne(*self, *other) }
     }

I didn't know this worked until recently, but since defining methods contravariantly in their lifetimes this way has worked back to Rust 1.0, we might as well take advantage of combining it with IHLE.

@scottmcm scottmcm added the T-libs label Mar 10, 2019

@rust-highfive rust-highfive assigned sfackler Mar 10, 2019

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rust-highfive commented Mar 10, 2019

r? @sfackler

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@rust-highfive rust-highfive added the S-waiting-on-review label Mar 10, 2019

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sfackler commented Mar 10, 2019

@bors r+ rollup
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bors commented Mar 10, 2019

📌 Commit df4ea90 has been approved by sfackler

@bors bors added S-waiting-on-bors and removed S-waiting-on-review labels Mar 10, 2019

Centril added a commit to Centril/rust that referenced this pull request Mar 10, 2019

@Centril
Rollup merge of rust-lang#59056 - scottmcm:even-fewer-lifetimes, r=sf… 
…ackler

Use lifetime contravariance to elide more lifetimes in core+alloc+std

Sample:
```diff
-    impl<'a, 'b, A: ?Sized, B: ?Sized> PartialEq<&'b mut B> for &'a mut A where A: PartialEq<B> {
+    impl<A: ?Sized, B: ?Sized> PartialEq<&mut B> for &mut A where A: PartialEq<B> {
         #[inline]
-        fn eq(&self, other: &&'b mut B) -> bool { PartialEq::eq(*self, *other) }
+        fn eq(&self, other: &&mut B) -> bool { PartialEq::eq(*self, *other) }
         #[inline]
-        fn ne(&self, other: &&'b mut B) -> bool { PartialEq::ne(*self, *other) }
+        fn ne(&self, other: &&mut B) -> bool { PartialEq::ne(*self, *other) }
     }
```

[I didn't know this worked](https://internals.rust-lang.org/t/why-can-you-use-different-unconstrained-lifetimes-to-implement-traits/9544/2?u=scottmcm) until recently, but since defining methods contravariantly in their lifetimes this way has worked back to Rust 1.0, we might as well take advantage of combining it with IHLE.
Verified
This commit was created on GitHub.com and signed with a verified signature using GitHub’s key.
GPG key ID: 4AEE18F83AFDEB23 Learn about signing commits
f5a17e8

@Centril Centril referenced this pull request Mar 10, 2019

Closed

Rollup of 16 pull requests #59066

Centril added a commit to Centril/rust that referenced this pull request Mar 10, 2019

@Centril
Rollup merge of rust-lang#59056 - scottmcm:even-fewer-lifetimes, r=sf… 
…ackler

Use lifetime contravariance to elide more lifetimes in core+alloc+std

Sample:
```diff
-    impl<'a, 'b, A: ?Sized, B: ?Sized> PartialEq<&'b mut B> for &'a mut A where A: PartialEq<B> {
+    impl<A: ?Sized, B: ?Sized> PartialEq<&mut B> for &mut A where A: PartialEq<B> {
         #[inline]
-        fn eq(&self, other: &&'b mut B) -> bool { PartialEq::eq(*self, *other) }
+        fn eq(&self, other: &&mut B) -> bool { PartialEq::eq(*self, *other) }
         #[inline]
-        fn ne(&self, other: &&'b mut B) -> bool { PartialEq::ne(*self, *other) }
+        fn ne(&self, other: &&mut B) -> bool { PartialEq::ne(*self, *other) }
     }
```

[I didn't know this worked](https://internals.rust-lang.org/t/why-can-you-use-different-unconstrained-lifetimes-to-implement-traits/9544/2?u=scottmcm) until recently, but since defining methods contravariantly in their lifetimes this way has worked back to Rust 1.0, we might as well take advantage of combining it with IHLE.
Verified
This commit was created on GitHub.com and signed with a verified signature using GitHub’s key.
GPG key ID: 4AEE18F83AFDEB23 Learn about signing commits
6a94f44

@Centril Centril referenced this pull request Mar 10, 2019

Closed

Rollup of 17 pull requests #59067

bors added a commit that referenced this pull request Mar 10, 2019

@bors
Auto merge of #59067 - Centril:rollup, r=Centril 
Rollup of 17 pull requests

Successful merges:

 - #58021 (Fix fallout from #57667)
 - #58330 (Add rustdoc JS non-std tests)
 - #58788 (Make migrate mode work at item level granularity)
 - #58789 (Update compiler_builtins to 0.1.7 to get windows/arm fix)
 - #58803 (fs::copy() linux: set file mode early)
 - #58829 (librustc_interface: Update scoped-tls to 1.0)
 - #58848 (Prevent cache issues on version updates)
 - #58855 (std: Spin for a global malloc lock on wasm32)
 - #58872 (Adds help message in error for invalid `impl for T` syntax)
 - #58876 (Parse lifetimes that start with a number and give specific error)
 - #58901 (Change `std::fs::copy` to use `copyfile` on MacOS and iOS)
 - #58938 (core: ensure VaList passes improper_ctypes lint)
 - #58941 (MIPS: add r6 support)
 - #59035 (When encountetring `||{}()`, suggest the likely intended `(||{})()`)
 - #59036 (Fix ICE in MIR pretty printing)
 - #59047 (resolve: Account for new importable entities)
 - #59056 (Use lifetime contravariance to elide more lifetimes in core+alloc+std)

Failed merges:

r? @ghost
Loading status checks…
8859e70

Centril added a commit to Centril/rust that referenced this pull request Mar 10, 2019

@Centril
Rollup merge of rust-lang#59056 - scottmcm:even-fewer-lifetimes, r=sf… 
…ackler

Use lifetime contravariance to elide more lifetimes in core+alloc+std

Sample:
```diff
-    impl<'a, 'b, A: ?Sized, B: ?Sized> PartialEq<&'b mut B> for &'a mut A where A: PartialEq<B> {
+    impl<A: ?Sized, B: ?Sized> PartialEq<&mut B> for &mut A where A: PartialEq<B> {
         #[inline]
-        fn eq(&self, other: &&'b mut B) -> bool { PartialEq::eq(*self, *other) }
+        fn eq(&self, other: &&mut B) -> bool { PartialEq::eq(*self, *other) }
         #[inline]
-        fn ne(&self, other: &&'b mut B) -> bool { PartialEq::ne(*self, *other) }
+        fn ne(&self, other: &&mut B) -> bool { PartialEq::ne(*self, *other) }
     }
```

[I didn't know this worked](https://internals.rust-lang.org/t/why-can-you-use-different-unconstrained-lifetimes-to-implement-traits/9544/2?u=scottmcm) until recently, but since defining methods contravariantly in their lifetimes this way has worked back to Rust 1.0, we might as well take advantage of combining it with IHLE.
Verified
This commit was created on GitHub.com and signed with a verified signature using GitHub’s key.
GPG key ID: 4AEE18F83AFDEB23 Learn about signing commits
4c49c7a

@Centril Centril referenced this pull request Mar 10, 2019

Closed

Rollup of 16 pull requests #59069

bors added a commit that referenced this pull request Mar 10, 2019

@bors
Auto merge of #59069 - Centril:rollup, r=Centril 
Rollup of 16 pull requests

Successful merges:

 - #58021 (Fix fallout from #57667)
 - #58330 (Add rustdoc JS non-std tests)
 - #58789 (Update compiler_builtins to 0.1.7 to get windows/arm fix)
 - #58803 (fs::copy() linux: set file mode early)
 - #58829 (librustc_interface: Update scoped-tls to 1.0)
 - #58848 (Prevent cache issues on version updates)
 - #58855 (std: Spin for a global malloc lock on wasm32)
 - #58872 (Adds help message in error for invalid `impl for T` syntax)
 - #58876 (Parse lifetimes that start with a number and give specific error)
 - #58901 (Change `std::fs::copy` to use `copyfile` on MacOS and iOS)
 - #58938 (core: ensure VaList passes improper_ctypes lint)
 - #58941 (MIPS: add r6 support)
 - #59035 (When encountetring `||{}()`, suggest the likely intended `(||{})()`)
 - #59036 (Fix ICE in MIR pretty printing)
 - #59047 (resolve: Account for new importable entities)
 - #59056 (Use lifetime contravariance to elide more lifetimes in core+alloc+std)

Failed merges:

r? @ghost
Loading status checks…
ab79b1e

Centril added a commit to Centril/rust that referenced this pull request Mar 10, 2019

@Centril
Rollup merge of rust-lang#59056 - scottmcm:even-fewer-lifetimes, r=sf… 
…ackler

Use lifetime contravariance to elide more lifetimes in core+alloc+std

Sample:
```diff
-    impl<'a, 'b, A: ?Sized, B: ?Sized> PartialEq<&'b mut B> for &'a mut A where A: PartialEq<B> {
+    impl<A: ?Sized, B: ?Sized> PartialEq<&mut B> for &mut A where A: PartialEq<B> {
         #[inline]
-        fn eq(&self, other: &&'b mut B) -> bool { PartialEq::eq(*self, *other) }
+        fn eq(&self, other: &&mut B) -> bool { PartialEq::eq(*self, *other) }
         #[inline]
-        fn ne(&self, other: &&'b mut B) -> bool { PartialEq::ne(*self, *other) }
+        fn ne(&self, other: &&mut B) -> bool { PartialEq::ne(*self, *other) }
     }
```

[I didn't know this worked](https://internals.rust-lang.org/t/why-can-you-use-different-unconstrained-lifetimes-to-implement-traits/9544/2?u=scottmcm) until recently, but since defining methods contravariantly in their lifetimes this way has worked back to Rust 1.0, we might as well take advantage of combining it with IHLE.
Verified
This commit was created on GitHub.com and signed with a verified signature using GitHub’s key.
GPG key ID: 4AEE18F83AFDEB23 Learn about signing commits
9fb05ce

@Centril Centril referenced this pull request Mar 10, 2019

Closed

Rollup of 17 pull requests #59075

bors added a commit that referenced this pull request Mar 10, 2019

@bors
Auto merge of #59075 - Centril:rollup, r=Centril 
Rollup of 17 pull requests

Successful merges:

 - #58021 (Fix fallout from #57667)
 - #58788 (Make migrate mode work at item level granularity)
 - #58789 (Update compiler_builtins to 0.1.7 to get windows/arm fix)
 - #58803 (fs::copy() linux: set file mode early)
 - #58829 (librustc_interface: Update scoped-tls to 1.0)
 - #58848 (Prevent cache issues on version updates)
 - #58855 (std: Spin for a global malloc lock on wasm32)
 - #58872 (Adds help message in error for invalid `impl for T` syntax)
 - #58876 (Parse lifetimes that start with a number and give specific error)
 - #58901 (Change `std::fs::copy` to use `copyfile` on MacOS and iOS)
 - #58938 (core: ensure VaList passes improper_ctypes lint)
 - #58941 (MIPS: add r6 support)
 - #59035 (When encountetring `||{}()`, suggest the likely intended `(||{})()`)
 - #59036 (Fix ICE in MIR pretty printing)
 - #59047 (resolve: Account for new importable entities)
 - #59056 (Use lifetime contravariance to elide more lifetimes in core+alloc+std)
 - #59072 (we can now skip should_panic tests with the libtest harness)

Failed merges:

r? @ghost
Loading status checks…
a90a39a

Centril added a commit to Centril/rust that referenced this pull request Mar 11, 2019

@Centril
Rollup merge of rust-lang#59056 - scottmcm:even-fewer-lifetimes, r=sf… 
…ackler

Use lifetime contravariance to elide more lifetimes in core+alloc+std

Sample:
```diff
-    impl<'a, 'b, A: ?Sized, B: ?Sized> PartialEq<&'b mut B> for &'a mut A where A: PartialEq<B> {
+    impl<A: ?Sized, B: ?Sized> PartialEq<&mut B> for &mut A where A: PartialEq<B> {
         #[inline]
-        fn eq(&self, other: &&'b mut B) -> bool { PartialEq::eq(*self, *other) }
+        fn eq(&self, other: &&mut B) -> bool { PartialEq::eq(*self, *other) }
         #[inline]
-        fn ne(&self, other: &&'b mut B) -> bool { PartialEq::ne(*self, *other) }
+        fn ne(&self, other: &&mut B) -> bool { PartialEq::ne(*self, *other) }
     }
```

[I didn't know this worked](https://internals.rust-lang.org/t/why-can-you-use-different-unconstrained-lifetimes-to-implement-traits/9544/2?u=scottmcm) until recently, but since defining methods contravariantly in their lifetimes this way has worked back to Rust 1.0, we might as well take advantage of combining it with IHLE.
Verified
This commit was created on GitHub.com and signed with a verified signature using GitHub’s key.
GPG key ID: 4AEE18F83AFDEB23 Learn about signing commits
25a31c4

@Centril Centril referenced this pull request Mar 11, 2019

Closed

Rollup of 15 pull requests #59081

bors added a commit that referenced this pull request Mar 11, 2019

@bors
Auto merge of #59081 - Centril:rollup, r=Centril 
Rollup of 15 pull requests

Successful merges:

 - #58021 (Fix fallout from #57667)
 - #58788 (Make migrate mode work at item level granularity)
 - #58789 (Update compiler_builtins to 0.1.7 to get windows/arm fix)
 - #58829 (librustc_interface: Update scoped-tls to 1.0)
 - #58848 (Prevent cache issues on version updates)
 - #58855 (std: Spin for a global malloc lock on wasm32)
 - #58872 (Adds help message in error for invalid `impl for T` syntax)
 - #58876 (Parse lifetimes that start with a number and give specific error)
 - #58938 (core: ensure VaList passes improper_ctypes lint)
 - #58941 (MIPS: add r6 support)
 - #59035 (When encountetring `||{}()`, suggest the likely intended `(||{})()`)
 - #59036 (Fix ICE in MIR pretty printing)
 - #59047 (resolve: Account for new importable entities)
 - #59056 (Use lifetime contravariance to elide more lifetimes in core+alloc+std)
 - #59072 (we can now skip should_panic tests with the libtest harness)

Failed merges:

r? @ghost
Loading status checks…
755d897

kennytm added a commit to kennytm/rust that referenced this pull request Mar 11, 2019

@kennytm
Rollup merge of rust-lang#59056 - scottmcm:even-fewer-lifetimes, r=sf… 
…ackler

Use lifetime contravariance to elide more lifetimes in core+alloc+std

Sample:
```diff
-    impl<'a, 'b, A: ?Sized, B: ?Sized> PartialEq<&'b mut B> for &'a mut A where A: PartialEq<B> {
+    impl<A: ?Sized, B: ?Sized> PartialEq<&mut B> for &mut A where A: PartialEq<B> {
         #[inline]
-        fn eq(&self, other: &&'b mut B) -> bool { PartialEq::eq(*self, *other) }
+        fn eq(&self, other: &&mut B) -> bool { PartialEq::eq(*self, *other) }
         #[inline]
-        fn ne(&self, other: &&'b mut B) -> bool { PartialEq::ne(*self, *other) }
+        fn ne(&self, other: &&mut B) -> bool { PartialEq::ne(*self, *other) }
     }
```

[I didn't know this worked](https://internals.rust-lang.org/t/why-can-you-use-different-unconstrained-lifetimes-to-implement-traits/9544/2?u=scottmcm) until recently, but since defining methods contravariantly in their lifetimes this way has worked back to Rust 1.0, we might as well take advantage of combining it with IHLE.
Verified
This commit was created on GitHub.com and signed with a verified signature using GitHub’s key.
GPG key ID: 4AEE18F83AFDEB23 Learn about signing commits
6c6ed57

@kennytm kennytm referenced this pull request Mar 11, 2019

Closed

Rollup of 23 pull requests #59108

pietroalbini added a commit to pietroalbini/rust that referenced this pull request Mar 12, 2019

@pietroalbini
Rollup merge of rust-lang#59056 - scottmcm:even-fewer-lifetimes, r=sf… 
…ackler

Use lifetime contravariance to elide more lifetimes in core+alloc+std

Sample:
```diff
-    impl<'a, 'b, A: ?Sized, B: ?Sized> PartialEq<&'b mut B> for &'a mut A where A: PartialEq<B> {
+    impl<A: ?Sized, B: ?Sized> PartialEq<&mut B> for &mut A where A: PartialEq<B> {
         #[inline]
-        fn eq(&self, other: &&'b mut B) -> bool { PartialEq::eq(*self, *other) }
+        fn eq(&self, other: &&mut B) -> bool { PartialEq::eq(*self, *other) }
         #[inline]
-        fn ne(&self, other: &&'b mut B) -> bool { PartialEq::ne(*self, *other) }
+        fn ne(&self, other: &&mut B) -> bool { PartialEq::ne(*self, *other) }
     }
```

[I didn't know this worked](https://internals.rust-lang.org/t/why-can-you-use-different-unconstrained-lifetimes-to-implement-traits/9544/2?u=scottmcm) until recently, but since defining methods contravariantly in their lifetimes this way has worked back to Rust 1.0, we might as well take advantage of combining it with IHLE.
Verified
This commit was created on GitHub.com and signed with a verified signature using GitHub’s key.
GPG key ID: 4AEE18F83AFDEB23 Learn about signing commits
9a62ebf

@pietroalbini pietroalbini referenced this pull request Mar 12, 2019

Closed

Rollup of 14 pull requests #59141

Centril added a commit to Centril/rust that referenced this pull request Mar 13, 2019

@Centril
Rollup merge of rust-lang#59056 - scottmcm:even-fewer-lifetimes, r=sf… 
…ackler

Use lifetime contravariance to elide more lifetimes in core+alloc+std

Sample:
```diff
-    impl<'a, 'b, A: ?Sized, B: ?Sized> PartialEq<&'b mut B> for &'a mut A where A: PartialEq<B> {
+    impl<A: ?Sized, B: ?Sized> PartialEq<&mut B> for &mut A where A: PartialEq<B> {
         #[inline]
-        fn eq(&self, other: &&'b mut B) -> bool { PartialEq::eq(*self, *other) }
+        fn eq(&self, other: &&mut B) -> bool { PartialEq::eq(*self, *other) }
         #[inline]
-        fn ne(&self, other: &&'b mut B) -> bool { PartialEq::ne(*self, *other) }
+        fn ne(&self, other: &&mut B) -> bool { PartialEq::ne(*self, *other) }
     }
```

[I didn't know this worked](https://internals.rust-lang.org/t/why-can-you-use-different-unconstrained-lifetimes-to-implement-traits/9544/2?u=scottmcm) until recently, but since defining methods contravariantly in their lifetimes this way has worked back to Rust 1.0, we might as well take advantage of combining it with IHLE.
Verified
This commit was created on GitHub.com and signed with a verified signature using GitHub’s key.
GPG key ID: 4AEE18F83AFDEB23 Learn about signing commits
68abd9a

@Centril Centril referenced this pull request Mar 13, 2019

Merged

Rollup of 16 pull requests #59151

bors added a commit that referenced this pull request Mar 13, 2019

@bors
Auto merge of #59151 - Centril:rollup, r=Centril 
Rollup of 16 pull requests

Successful merges:

 - #58829 (librustc_interface: Update scoped-tls to 1.0)
 - #58876 (Parse lifetimes that start with a number and give specific error)
 - #58908 (Update rand version)
 - #58998 (Fix documentation of from_ne_bytes and from_le_bytes)
 - #59056 (Use lifetime contravariance to elide more lifetimes in core+alloc+std)
 - #59057 (Standardize `Range*` documentation)
 - #59080 (Fix incorrect links in librustc_codegen_llvm documentation)
 - #59083 (Fix #54822 and associated faulty tests)
 - #59093 (Remove precompute_in_scope_traits_hashes)
 - #59101 (Reduces Code Repetitions like `!n >> amt`)
 - #59121 (impl FromIterator for Result: Use assert_eq! instead of assert!)
 - #59124 (Replace assert with assert_eq)
 - #59129 (Visit impl Trait for dead_code lint)
 - #59130 (Note that NonNull does not launder shared references for mutation)
 - #59132 (ignore higher-ranked object bound conditions created by WF)
 - #59138 (Simplify Iterator::{min, max})

Failed merges:

r? @ghost
Loading status checks…
aa97448

@bors bors merged commit df4ea90 into rust-lang:master Mar 13, 2019

@scottmcm scottmcm deleted the scottmcm:even-fewer-lifetimes branch Mar 13, 2019

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