3fb1230adc
literal pattern lowering: use the pattern's type instead of the literal's in `const_to_pat` This has two purposes: - First, it enables removing the `treat_byte_string_as_slice` fields from `TypeckResults` and `ConstToPat`. A byte string pattern's type will be `&[u8]` when matching on a slice reference, so `const_to_pat` will lower it to a slice ref pattern. I believe this is tested by `tests/ui/match/pattern-deref-miscompile.rs`. - Second, it will simplify the implementation of byte string literals in deref patterns. If byte string patterns can be given the type `[u8; N]` or `[u8]` during HIR typeck, then nothing needs to be changed in `const_to_pat` in order to lower the patterns `deref!(b"..."): Vec<u8>` and `deref!(b"..."): Box<[u8; 3]>`. Implementation-wise, this uses `lit_to_const` to make a const with the pattern's type and the literal's valtree; that feels to me like the best way to make sure that the valtree representations of the pattern type and literal are the same. Though it may necessitate later changes to `lit_to_const` to accommodate giving byte string literal patterns non-reference types—would that be reasonable? This unfortunately doesn't work for the `string_deref_patterns` feature (since that gives string literal patterns the `String` type), so I added a workaround for that. However, once `deref_patterns` supports string literals, it may be able to replace `string_deref_patterns`; the special case for `String` can removed at that point. r? ``@oli-obk`` |
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| assembly | ||
| auxiliary | ||
| codegen | ||
| codegen-units | ||
| coverage | ||
| coverage-run-rustdoc | ||
| crashes | ||
| debuginfo | ||
| incremental | ||
| mir-opt | ||
| pretty | ||
| run-make | ||
| rustdoc | ||
| rustdoc-gui | ||
| rustdoc-js | ||
| rustdoc-js-std | ||
| rustdoc-json | ||
| rustdoc-ui | ||
| ui | ||
| ui-fulldeps | ||
| COMPILER_TESTS.md | ||