bjoernager/rust
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Properly replace impl Trait in fn args, turn {integer} to i32

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This commit is contained in:
Michael Goulet 2022-06-05 18:56:26 -07:00
parent 55805ab473
commit 38d7e2734f
5 changed files with 76 additions and 12 deletions
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39
compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
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@ -372,21 +372,34 @@ fn suggest_restriction<'tcx>(
// but instead we choose to suggest replacing all instances of `impl Trait` with `T`
// where `T: Trait`.
let mut ty_spans = vec![];
let impl_trait_str = format!("impl {}", bound_str);
for input in fn_sig.decl.inputs {
if let hir::TyKind::Path(hir::QPath::Resolved(
None,
hir::Path { segments: [segment], .. },
)) = input.kind
{
if segment.ident.as_str() == impl_trait_str.as_str() {
// `fn foo(t: impl Trait)`
// ^^^^^^^^^^ get this to suggest `T` instead
struct ReplaceImplTraitVisitor<'a> {
ty_spans: &'a mut Vec<Span>,
bound_str: &'a str,
}
impl<'a, 'hir> hir::intravisit::Visitor<'hir> for ReplaceImplTraitVisitor<'a> {
fn visit_ty(&mut self, t: &'hir hir::Ty<'hir>) {
if let hir::TyKind::Path(hir::QPath::Resolved(
None,
hir::Path { segments: [segment], .. },
)) = t.kind
{
if segment.ident.as_str().strip_prefix("impl ").map(|s| s.trim_start())
== Some(self.bound_str)
{
// `fn foo(t: impl Trait)`
// ^^^^^^^^^^ get this to suggest `T` instead
// There might be more than one `impl Trait`.
ty_spans.push(input.span);
// There might be more than one `impl Trait`.
self.ty_spans.push(t.span);
return;
}
}
hir::intravisit::walk_ty(self, t);
}
}
ReplaceImplTraitVisitor { ty_spans: &mut ty_spans, bound_str: &bound_str }
.visit_ty(input);
}
let type_param_name = generics.params.next_type_param_name(Some(&bound_str));
@ -396,7 +409,7 @@ fn suggest_restriction<'tcx>(
// FIXME: modify the `trait_pred` instead of string shenanigans.
// Turn `<impl Trait as Foo>::Bar: Qux` into `<T as Foo>::Bar: Qux`.
let pred = trait_pred.to_predicate(tcx).to_string();
let pred = pred.replace(&impl_trait_str, &type_param_name);
let pred = pred.replace(&format!("impl {}", bound_str), &type_param_name);
let mut sugg = vec![
if let Some(span) = generics.span_for_param_suggestion() {
(span, format!(", {}", type_param))
@ -460,6 +473,8 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
trait_pred: ty::PolyTraitPredicate<'tcx>,
body_id: hir::HirId,
) {
let trait_pred = self.resolve_numeric_literals_with_default(trait_pred);
let self_ty = trait_pred.skip_binder().self_ty();
let (param_ty, projection) = match self_ty.kind() {
ty::Param(_) => (true, None),