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Fix inline const pattern unsafety checking in THIR

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THIR unsafety checking was getting a cycle of
function unsafety checking
-> building THIR for the function
-> evaluating pattern inline constants in the function
-> building MIR for the inline constant
-> checking unsafety of functions (so that THIR can be stolen)
This is fixed by not stealing THIR when generating MIR but instead when
unsafety checking.
This leaves an issue with pattern inline constants not being unsafety
checked because they are evaluated away when generating THIR.
To fix that we now represent inline constants in THIR patterns and
visit them in THIR unsafety checking.
This commit is contained in:
Matthew Jasper
2023-10-05 14:57:14 +00:00
parent e7bdc5f9f8
commit 5cc83fd4a5
24 changed files with 239 additions and 50 deletions
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25
compiler/rustc_mir_build/src/build/mod.rs
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@@ -53,10 +53,7 @@ pub(crate) fn closure_saved_names_of_captured_variables<'tcx>(
}
/// Construct the MIR for a given `DefId`.
fn mir_build(tcx: TyCtxt<'_>, def: LocalDefId) -> Body<'_> {
// Ensure unsafeck and abstract const building is ran before we steal the THIR.
tcx.ensure_with_value()
.thir_check_unsafety(tcx.typeck_root_def_id(def.to_def_id()).expect_local());
fn mir_build<'tcx>(tcx: TyCtxt<'tcx>, def: LocalDefId) -> Body<'tcx> {
tcx.ensure_with_value().thir_abstract_const(def);
if let Err(e) = tcx.check_match(def) {
return construct_error(tcx, def, e);
@@ -65,9 +62,10 @@ fn mir_build(tcx: TyCtxt<'_>, def: LocalDefId) -> Body<'_> {
let body = match tcx.thir_body(def) {
Err(error_reported) => construct_error(tcx, def, error_reported),
Ok((thir, expr)) => {
// We ran all queries that depended on THIR at the beginning
// of `mir_build`, so now we can steal it
let thir = thir.steal();
let build_mir = |thir: &Thir<'tcx>| match thir.body_type {
thir::BodyTy::Fn(fn_sig) => construct_fn(tcx, def, thir, expr, fn_sig),
thir::BodyTy::Const(ty) => construct_const(tcx, def, thir, expr, ty),
};
tcx.ensure().check_match(def);
// this must run before MIR dump, because
@@ -76,9 +74,16 @@ fn mir_build(tcx: TyCtxt<'_>, def: LocalDefId) -> Body<'_> {
// maybe move the check to a MIR pass?
tcx.ensure().check_liveness(def);
match thir.body_type {
thir::BodyTy::Fn(fn_sig) => construct_fn(tcx, def, &thir, expr, fn_sig),
thir::BodyTy::Const(ty) => construct_const(tcx, def, &thir, expr, ty),
if tcx.sess.opts.unstable_opts.thir_unsafeck {
// Don't steal here if THIR unsafeck is being used. Instead
// steal in unsafeck. This is so that pattern inline constants
// can be evaluated as part of building the THIR of the parent
// function without a cycle.
build_mir(&thir.borrow())
} else {
// We ran all queries that depended on THIR at the beginning
// of `mir_build`, so now we can steal it
build_mir(&thir.steal())
}
}
};