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Auto merge of #111047 - compiler-errors:rtn-no-ty-ct-params, r=spastorino

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Emit an error when return-type-notation is used with type/const params

These are not intended to be supported initially, even though the compiler supports them internally...
This commit is contained in:
bors 2023-06-07 09:03:33 +00:00
commit e94bda3bf1
8 changed files with 100 additions and 44 deletions
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63
compiler/rustc_hir_analysis/src/astconv/mod.rs
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@ -26,10 +26,8 @@ use rustc_hir::def::{CtorOf, DefKind, Namespace, Res};
use rustc_hir::def_id::{DefId, LocalDefId};
use rustc_hir::intravisit::{walk_generics, Visitor as _};
use rustc_hir::{GenericArg, GenericArgs, OpaqueTyOrigin};
use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
use rustc_infer::infer::{InferCtxt, TyCtxtInferExt};
use rustc_infer::traits::ObligationCause;
use rustc_middle::infer::unify_key::{ConstVariableOrigin, ConstVariableOriginKind};
use rustc_middle::middle::stability::AllowUnstable;
use rustc_middle::ty::fold::FnMutDelegate;
use rustc_middle::ty::subst::{self, GenericArgKind, InternalSubsts, SubstsRef};
@ -1215,6 +1213,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
}
let projection_ty = if return_type_notation {
let mut emitted_bad_param_err = false;
// If we have an method return type bound, then we need to substitute
// the method's early bound params with suitable late-bound params.
let mut num_bound_vars = candidate.bound_vars().len();
@ -1230,16 +1229,35 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
},
)
.into(),
GenericParamDefKind::Type { .. } => tcx
.mk_bound(
GenericParamDefKind::Type { .. } => {
if !emitted_bad_param_err {
tcx.sess.emit_err(
crate::errors::ReturnTypeNotationIllegalParam::Type {
span: path_span,
param_span: tcx.def_span(param.def_id),
},
);
emitted_bad_param_err = true;
}
tcx.mk_bound(
ty::INNERMOST,
ty::BoundTy {
var: ty::BoundVar::from_usize(num_bound_vars),
kind: ty::BoundTyKind::Param(param.def_id, param.name),
},
)
.into(),
.into()
}
GenericParamDefKind::Const { .. } => {
if !emitted_bad_param_err {
tcx.sess.emit_err(
crate::errors::ReturnTypeNotationIllegalParam::Const {
span: path_span,
param_span: tcx.def_span(param.def_id),
},
);
emitted_bad_param_err = true;
}
let ty = tcx
.type_of(param.def_id)
.no_bound_vars()
@ -2472,7 +2490,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
infcx.probe(|_| {
let ocx = ObligationCtxt::new_in_snapshot(&infcx);
let impl_substs = infcx.fresh_item_substs(impl_);
let impl_substs = infcx.fresh_substs_for_item(span, impl_);
let impl_ty = tcx.type_of(impl_).subst(tcx, impl_substs);
let impl_ty = ocx.normalize(&cause, param_env, impl_ty);
@ -3759,36 +3777,3 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
}
}
}
pub trait InferCtxtExt<'tcx> {
fn fresh_item_substs(&self, def_id: DefId) -> SubstsRef<'tcx>;
}
impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
fn fresh_item_substs(&self, def_id: DefId) -> SubstsRef<'tcx> {
InternalSubsts::for_item(self.tcx, def_id, |param, _| match param.kind {
GenericParamDefKind::Lifetime => self.tcx.lifetimes.re_erased.into(),
GenericParamDefKind::Type { .. } => self
.next_ty_var(TypeVariableOrigin {
kind: TypeVariableOriginKind::SubstitutionPlaceholder,
span: self.tcx.def_span(def_id),
})
.into(),
GenericParamDefKind::Const { .. } => {
let span = self.tcx.def_span(def_id);
let origin = ConstVariableOrigin {
kind: ConstVariableOriginKind::SubstitutionPlaceholder,
span,
};
self.next_const_var(
self.tcx
.type_of(param.def_id)
.no_bound_vars()
.expect("const parameter types cannot be generic"),
origin,
)
.into()
}
})
}
}