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fix gce typing_mode mismatch

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This commit is contained in:
lcnr 2024-11-25 19:41:13 +01:00
parent 7db7489f9b
commit 58936c1d2a
3 changed files with 89 additions and 18 deletions
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43
compiler/rustc_trait_selection/src/traits/mod.rs
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@ -551,8 +551,18 @@ pub fn try_evaluate_const<'tcx>(
| ty::ConstKind::Placeholder(_)
| ty::ConstKind::Expr(_) => Err(EvaluateConstErr::HasGenericsOrInfers),
ty::ConstKind::Unevaluated(uv) => {
// Postpone evaluation of constants that depend on generic parameters or inference variables.
let (args, param_env) = if tcx.features().generic_const_exprs()
// Postpone evaluation of constants that depend on generic parameters or
// inference variables.
//
// We use `TypingMode::PostAnalysis` here which is not *technically* correct
// to be revealing opaque types here as borrowcheck has not run yet. However,
// CTFE itself uses `TypingMode::PostAnalysis` unconditionally even during
// typeck and not doing so has a lot of (undesirable) fallout (#101478, #119821).
// As a result we always use a revealed env when resolving the instance to evaluate.
//
// FIXME: `const_eval_resolve_for_typeck` should probably just modify the env itself
// instead of having this logic here
let (args, typing_env) = if tcx.features().generic_const_exprs()
&& uv.has_non_region_infer()
{
// `feature(generic_const_exprs)` causes anon consts to inherit all parent generics. This can cause
@ -568,13 +578,17 @@ pub fn try_evaluate_const<'tcx>(
// the generic arguments provided for it, then we should *not* attempt to evaluate it.
return Err(EvaluateConstErr::HasGenericsOrInfers);
} else {
(replace_param_and_infer_args_with_placeholder(tcx, uv.args), param_env)
let args = replace_param_and_infer_args_with_placeholder(tcx, uv.args);
let typing_env = infcx
.typing_env(tcx.erase_regions(param_env))
.with_post_analysis_normalized(tcx);
(args, typing_env)
}
}
Err(_) | Ok(None) => {
let args = GenericArgs::identity_for_item(tcx, uv.def);
let param_env = tcx.param_env(uv.def);
(args, param_env)
let typing_env = ty::TypingEnv::post_analysis(tcx, uv.def);
(args, typing_env)
}
}
} else if tcx.def_kind(uv.def) == DefKind::AnonConst && uv.has_non_region_infer() {
@ -593,27 +607,20 @@ pub fn try_evaluate_const<'tcx>(
);
let args = GenericArgs::identity_for_item(tcx, uv.def);
let param_env = tcx.param_env(uv.def);
(args, param_env)
let typing_env = ty::TypingEnv::post_analysis(tcx, uv.def);
(args, typing_env)
} else {
// FIXME: This codepath is reachable under `associated_const_equality` and in the
// future will be reachable by `min_generic_const_args`. We should handle inference
// variables and generic parameters properly instead of doing nothing.
(uv.args, param_env)
let typing_env = infcx
.typing_env(tcx.erase_regions(param_env))
.with_post_analysis_normalized(tcx);
(uv.args, typing_env)
};
let uv = ty::UnevaluatedConst::new(uv.def, args);
// It's not *technically* correct to be revealing opaque types here as borrowcheck has
// not run yet. However, CTFE itself uses `TypingMode::PostAnalysis` unconditionally even
// during typeck and not doing so has a lot of (undesirable) fallout (#101478, #119821).
// As a result we always use a revealed env when resolving the instance to evaluate.
//
// FIXME: `const_eval_resolve_for_typeck` should probably just modify the env itself
// instead of having this logic here
let typing_env =
tcx.erase_regions(infcx.typing_env(param_env)).with_post_analysis_normalized(tcx);
let erased_uv = tcx.erase_regions(uv);
use rustc_middle::mir::interpret::ErrorHandled;
match tcx.const_eval_resolve_for_typeck(typing_env, erased_uv, DUMMY_SP) {
Ok(Ok(val)) => Ok(ty::Const::new_value(