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Consolidate type system const evaluation under traits::evaluate_const

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mew
This commit is contained in:
Boxy
2024-11-12 02:54:03 +00:00
parent 81eef2d362
commit bea0148ac6
31 changed files with 434 additions and 569 deletions
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31
compiler/rustc_trait_selection/src/traits/const_evaluatable.rs
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@@ -12,13 +12,13 @@
use rustc_hir::def::DefKind;
use rustc_infer::infer::InferCtxt;
use rustc_middle::bug;
use rustc_middle::mir::interpret::ErrorHandled;
use rustc_middle::traits::ObligationCause;
use rustc_middle::ty::abstract_const::NotConstEvaluatable;
use rustc_middle::ty::{self, TyCtxt, TypeVisitable, TypeVisitableExt, TypeVisitor};
use rustc_span::{DUMMY_SP, Span};
use tracing::{debug, instrument};
use super::EvaluateConstErr;
use crate::traits::ObligationCtxt;
/// Check if a given constant can be evaluated.
@@ -68,16 +68,18 @@ pub fn is_const_evaluatable<'tcx>(
// here.
tcx.dcx().span_bug(span, "evaluating `ConstKind::Expr` is not currently supported");
}
ty::ConstKind::Unevaluated(uv) => {
let concrete = infcx.const_eval_resolve(param_env, uv, span);
match concrete {
Err(ErrorHandled::TooGeneric(_)) => {
ty::ConstKind::Unevaluated(_) => {
match crate::traits::try_evaluate_const(infcx, unexpanded_ct, param_env) {
Err(EvaluateConstErr::HasGenericsOrInfers) => {
Err(NotConstEvaluatable::Error(infcx.dcx().span_delayed_bug(
span,
"Missing value for constant, but no error reported?",
)))
}
Err(ErrorHandled::Reported(e, _)) => Err(NotConstEvaluatable::Error(e.into())),
Err(
EvaluateConstErr::EvaluationFailure(e)
| EvaluateConstErr::InvalidConstParamTy(e),
) => Err(NotConstEvaluatable::Error(e.into())),
Ok(_) => Ok(()),
}
}
@@ -92,16 +94,7 @@ pub fn is_const_evaluatable<'tcx>(
_ => bug!("unexpected constkind in `is_const_evalautable: {unexpanded_ct:?}`"),
};
// FIXME: We should only try to evaluate a given constant here if it is fully concrete
// as we don't want to allow things like `[u8; std::mem::size_of::<*mut T>()]`.
//
// We previously did not check this, so we only emit a future compat warning if
// const evaluation succeeds and the given constant is still polymorphic for now
// and hopefully soon change this to an error.
//
// See #74595 for more details about this.
let concrete = infcx.const_eval_resolve(param_env, uv, span);
match concrete {
match crate::traits::try_evaluate_const(infcx, unexpanded_ct, param_env) {
// If we're evaluating a generic foreign constant, under a nightly compiler while
// the current crate does not enable `feature(generic_const_exprs)`, abort
// compilation with a useful error.
@@ -130,7 +123,7 @@ pub fn is_const_evaluatable<'tcx>(
.emit()
}
Err(ErrorHandled::TooGeneric(_)) => {
Err(EvaluateConstErr::HasGenericsOrInfers) => {
let err = if uv.has_non_region_infer() {
NotConstEvaluatable::MentionsInfer
} else if uv.has_non_region_param() {
@@ -145,7 +138,9 @@ pub fn is_const_evaluatable<'tcx>(
Err(err)
}
Err(ErrorHandled::Reported(e, _)) => Err(NotConstEvaluatable::Error(e.into())),
Err(
EvaluateConstErr::EvaluationFailure(e) | EvaluateConstErr::InvalidConstParamTy(e),
) => Err(NotConstEvaluatable::Error(e.into())),
Ok(_) => Ok(()),
}
}