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![]() Prototype: Add unstable `-Z reference-niches` option MCP: rust-lang/compiler-team#641 Relevant RFC: rust-lang/rfcs#3204 This prototype adds a new `-Z reference-niches` option, controlling the range of valid bit-patterns for reference types (`&T` and `&mut T`), thereby enabling new enum niching opportunities. Like `-Z randomize-layout`, this setting is crate-local; as such, references to built-in types (primitives, tuples, ...) are not affected. The possible settings are (here, `MAX` denotes the all-1 bit-pattern): | `-Z reference-niches=` | Valid range | |:---:|:---:| | `null` (the default) | `1..=MAX` | | `size` | `1..=(MAX- size)` | | `align` | `align..=MAX.align_down_to(align)` | | `size,align` | `align..=(MAX-size).align_down_to(align)` | ------ This is very WIP, and I'm not sure the approach I've taken here is the best one, but stage 1 tests pass locally; I believe this is in a good enough state to unleash this upon unsuspecting 3rd-party code, and see what breaks. |
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assembly | ||
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codegen | ||
codegen-units | ||
debuginfo | ||
incremental | ||
mir-opt | ||
pretty | ||
run-coverage | ||
run-coverage-rustdoc | ||
run-make | ||
run-make-fulldeps | ||
run-pass-valgrind | ||
rustdoc | ||
rustdoc-gui | ||
rustdoc-js | ||
rustdoc-js-std | ||
rustdoc-json | ||
rustdoc-ui | ||
ui | ||
ui-fulldeps | ||
COMPILER_TESTS.md |