Introduce String::remove_matches to remove all matches of a pattern in a string.

[frewsxcv]

Like replace(..., ""), but doesn't result in any allocations.

[rust-highfive]

r? @aidanhs

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[frewsxcv]

note that this doesn't compile, because into_searcher immutably borrows the string, and i can't call self.vec.set_len below if it's borrowed. not sure how to proceed

[frewsxcv]

Also into_searcher consumes itself, so there's no way to call it again on a new string slice

[rust-highfive]

Your PR failed on Travis (raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

[00:00:50] configure: rust.quiet-tests     := True
---
[00:03:25] error[E0597]: `s` does not live long enough
[00:03:25]     --> liballoc/string.rs:1229:51
[00:03:25]      |
[00:03:25] 1229 |             let mut searcher = pat.into_searcher(&s);
[00:03:25]      |                                                   ^ borrowed value does not live long enough
[00:03:25] ...
[00:03:25] 1243 |         }
[00:03:25]      |         - borrowed value only lives until here
[00:03:25]      |
[00:03:25] note: borrowed value must be valid for the lifetime 'a as defined on the method body at 1217:5...
[00:03:25]     --> liballoc/string.rs:1217:5
[00:03:25]      |
[00:03:25] 1217 | /     pub fn remove_matches<'a, P>(&'a mut self, pat: P)
[00:03:25] 1218 | |     where
[00:03:25] 1219 | |         P: Pattern<'a>,
[00:03:25] 1220 | |     {
[00:03:25] ...    |
[00:03:25] 1243 | |         }
[00:03:25] 1244 | |     }
[00:03:25]      | |_____^
[00:03:25]
[00:03:25] error[E0382]: use of moved value: `pat`
[00:03:25]     --> liballoc/string.rs:1229:32
[00:03:25]      |
[00:03:25] 1229 |             let mut searcher = pat.into_searcher(&s);
[00:03:25]      |                                ^^^ value moved here in previous iteration of loop
[00:03:25]      |
[00:03:25]      = note: move occurs because `pat` has type `P`, which does not implement the `Copy` trait
[00:03:25]
[00:03:25] error: aborting due to 2 previous errors
[00:03:25]
[00:03:25] Some errors occurred: E0382, E0597.
[00:03:25] For more information about an error, try `rustc --explain E0382`.
[00:03:25] error: Could not compile `alloc`.
[00:03:25]
[00:03:25] Caused by:
[00:03:25]   process didn't exit successfully: `/checkout/obj/build/bootstrap/debug/rustc --crate-name alloc liballoc/lib.rs --color always --error-format json --crate-type lib --emit=dep-info,link -C opt-level=2 -C metadata=d3eb5884eb70b0b8 -C extra-filename=-d3eb5884eb70b0b8 --out-dir /checkout/obj/build/x86_64-unknown-linux-gnu/stage0-std/x86_64-unknown-linux-gnu/release/deps --target x86_64-unknown-linux-gnu -L dependency=/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-std/x86_64-unknown-linux-gnu/release/deps -L dependency=/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-std/release/deps --extern compiler_builtins=/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-std/x86_64-unknown-linux-gnu/release/deps/libcompiler_builtins-a2d7f090df844ebf.rlib --extern core=/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-std/x86_64-unknown-linux-gnu/release/deps/libcore-1b8789e893adb899.rlib -L native=/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-std/x86_64-unknown-linux-gnu/release/build/compiler_builtins-6789d0ad544f7553/out` (exit code: 101)
---
$ dmesg | grep -i kill
[   10.758087] init: failsafe main process (1096) killed by TERM signal

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @TimNN. (Feature Requests)

[TimNN]

@frewsxcv: How do you want to proceed with this PR? You mention that it currently doesn't compile, is that a problem with the pattern API or something in this PR that can be fixed?

[frewsxcv]

convertinig this to a github issue #50206