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Suggest return type for async function without return type

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This commit is contained in:
许杰友 Jieyou Xu (Joe) 2023-02-05 14:22:41 +08:00
parent 50d3ba5bcb
commit 6b05b80690
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GPG key ID: C5FD5D32014FDB47
4 changed files with 102 additions and 1 deletions
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16
compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs
View file

@ -921,6 +921,22 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
kind: hir::ImplItemKind::Fn(ref sig, ..),
..
}) => Some((&sig.decl, ident, false)),
Node::Expr(&hir::Expr {
hir_id,
kind: hir::ExprKind::Closure(..),
..
}) if let Some(Node::Expr(&hir::Expr {
hir_id,
kind: hir::ExprKind::Call(..),
..
})) = self.tcx.hir().find_parent(hir_id) &&
let Some(Node::Item(&hir::Item {
ident,
kind: hir::ItemKind::Fn(ref sig, ..),
..
})) = self.tcx.hir().find_parent(hir_id) => {
Some((&sig.decl, ident, ident.name != sym::main))
},
_ => None,
}
}

30
compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
View file

@ -704,10 +704,38 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
}
}
hir::FnRetTy::Return(ty) => {
let span = ty.span;
if let hir::TyKind::OpaqueDef(item_id, ..) = ty.kind
&& let hir::Node::Item(hir::Item {
kind: hir::ItemKind::OpaqueTy(op_ty),
..
}) = self.tcx.hir().get(item_id.hir_id())
&& let hir::OpaqueTy {
bounds: [bound], ..
} = op_ty
&& let hir::GenericBound::LangItemTrait(
hir::LangItem::Future, _, _, generic_args) = bound
&& let hir::GenericArgs { bindings: [ty_binding], .. } = generic_args
&& let hir::TypeBinding { kind, .. } = ty_binding
&& let hir::TypeBindingKind::Equality { term } = kind
&& let hir::Term::Ty(term_ty) = term {
// Check if async function's return type was omitted.
// Don't emit suggestions if the found type is `impl Future<...>`.
debug!("suggest_missing_return_type: found = {:?}", found);
if found.is_suggestable(self.tcx, false) {
if term_ty.span.is_empty() {
err.subdiagnostic(AddReturnTypeSuggestion::Add { span, found: found.to_string() });
return true;
} else {
err.subdiagnostic(ExpectedReturnTypeLabel::Other { span, expected });
}
}
}
// Only point to return type if the expected type is the return type, as if they
// are not, the expectation must have been caused by something else.
debug!("suggest_missing_return_type: return type {:?} node {:?}", ty, ty.kind);
let span = ty.span;
let ty = self.astconv().ast_ty_to_ty(ty);
debug!("suggest_missing_return_type: return type {:?}", ty);
debug!("suggest_missing_return_type: expected type {:?}", ty);