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Auto merge of #126679 - fmease:rollup-njrv2py, r=fmease

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Rollup of 6 pull requests

Successful merges:

 - #125447 (Allow constraining opaque types during subtyping in the trait system)
 - #125766 (MCDC Coverage: instrument last boolean RHS operands from condition coverage)
 - #125880 (Remove `src/tools/rust-demangler`)
 - #126154 (StorageLive: refresh storage (instead of UB) when local is already live)
 - #126572 (override user defined channel when using precompiled rustc)
 - #126662 (Unconditionally warn on usage of `wasm32-wasi`)

r? `@ghost`
`@rustbot` modify labels: rollup
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bors 2024-06-19 11:09:31 +00:00
commit 3186d17d56
35 changed files with 675 additions and 588 deletions
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11
compiler/rustc_middle/src/mir/syntax.rs
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@ -361,16 +361,19 @@ pub enum StatementKind<'tcx> {
/// At any point during the execution of a function, each local is either allocated or
/// unallocated. Except as noted below, all locals except function parameters are initially
/// unallocated. `StorageLive` statements cause memory to be allocated for the local while
/// `StorageDead` statements cause the memory to be freed. Using a local in any way (not only
/// reading/writing from it) while it is unallocated is UB.
/// `StorageDead` statements cause the memory to be freed. In other words,
/// `StorageLive`/`StorageDead` act like the heap operations `allocate`/`deallocate`, but for
/// stack-allocated local variables. Using a local in any way (not only reading/writing from it)
/// while it is unallocated is UB.
///
/// Some locals have no `StorageLive` or `StorageDead` statements within the entire MIR body.
/// These locals are implicitly allocated for the full duration of the function. There is a
/// convenience method at `rustc_mir_dataflow::storage::always_storage_live_locals` for
/// computing these locals.
///
/// If the local is already allocated, calling `StorageLive` again is UB. However, for an
/// unallocated local an additional `StorageDead` all is simply a nop.
/// If the local is already allocated, calling `StorageLive` again will implicitly free the
/// local and then allocate fresh uninitilized memory. If a local is already deallocated,
/// calling `StorageDead` again is a NOP.
StorageLive(Local),
/// See `StorageLive` above.