diff --git a/compiler/rustc_trait_selection/src/traits/mod.rs b/compiler/rustc_trait_selection/src/traits/mod.rs index 7d6c38c11f31..069fab6a6e6b 100644 --- a/compiler/rustc_trait_selection/src/traits/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/mod.rs @@ -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( diff --git a/tests/ui/const-generics/generic_const_exprs/post-analysis-user-facing-param-env.rs b/tests/ui/const-generics/generic_const_exprs/post-analysis-user-facing-param-env.rs new file mode 100644 index 000000000000..e5af632da757 --- /dev/null +++ b/tests/ui/const-generics/generic_const_exprs/post-analysis-user-facing-param-env.rs @@ -0,0 +1,18 @@ +// Regression test for #133271. +#![feature(generic_const_exprs)] +//~^ WARN the feature `generic_const_exprs` is incomplete + +struct Foo; +impl<'a, const NUM: usize> std::ops::Add<&'a Foo> for Foo +//~^ ERROR the const parameter `NUM` is not constrained by the impl trait, self type, or predicates +where + [(); 1 + 0]: Sized, +{ + fn unimplemented(self, _: &Foo) -> Self::Output { + //~^ ERROR method `unimplemented` is not a member of trait `std::ops::Add` + //~| ERROR type annotations needed + loop {} + } +} + +fn main() {} diff --git a/tests/ui/const-generics/generic_const_exprs/post-analysis-user-facing-param-env.stderr b/tests/ui/const-generics/generic_const_exprs/post-analysis-user-facing-param-env.stderr new file mode 100644 index 000000000000..ade18eb88b90 --- /dev/null +++ b/tests/ui/const-generics/generic_const_exprs/post-analysis-user-facing-param-env.stderr @@ -0,0 +1,46 @@ +error[E0407]: method `unimplemented` is not a member of trait `std::ops::Add` + --> $DIR/post-analysis-user-facing-param-env.rs:11:5 + | +LL | / fn unimplemented(self, _: &Foo) -> Self::Output { +LL | | +LL | | +LL | | loop {} +LL | | } + | |_____^ not a member of trait `std::ops::Add` + +warning: the feature `generic_const_exprs` is incomplete and may not be safe to use and/or cause compiler crashes + --> $DIR/post-analysis-user-facing-param-env.rs:2:12 + | +LL | #![feature(generic_const_exprs)] + | ^^^^^^^^^^^^^^^^^^^ + | + = note: see issue #76560 for more information + = note: `#[warn(incomplete_features)]` on by default + +error[E0207]: the const parameter `NUM` is not constrained by the impl trait, self type, or predicates + --> $DIR/post-analysis-user-facing-param-env.rs:6:10 + | +LL | impl<'a, const NUM: usize> std::ops::Add<&'a Foo> for Foo + | ^^^^^^^^^^^^^^^^ unconstrained const parameter + | + = note: expressions using a const parameter must map each value to a distinct output value + = note: proving the result of expressions other than the parameter are unique is not supported + +error[E0284]: type annotations needed + --> $DIR/post-analysis-user-facing-param-env.rs:11:40 + | +LL | fn unimplemented(self, _: &Foo) -> Self::Output { + | ^^^^^^^^^^^^ cannot infer the value of const parameter `NUM` + | +note: required for `Foo` to implement `Add<&'a Foo>` + --> $DIR/post-analysis-user-facing-param-env.rs:6:28 + | +LL | impl<'a, const NUM: usize> std::ops::Add<&'a Foo> for Foo + | ---------------- ^^^^^^^^^^^^^^^^^^^^^^ ^^^ + | | + | unsatisfied trait bound introduced here + +error: aborting due to 3 previous errors; 1 warning emitted + +Some errors have detailed explanations: E0207, E0284, E0407. +For more information about an error, try `rustc --explain E0207`.