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Fix suggestion when there are generics, inline some things

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This commit is contained in:
Michael Goulet 2025-03-08 20:20:15 +00:00
parent bca0ab8d7a
commit ceb040135d
3 changed files with 50 additions and 17 deletions
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46
compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs
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@ -78,13 +78,16 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
}
if self_ty.span.edition().at_least_rust_2021() {
let msg = "expected a type, found a trait";
let label = "you can add the `dyn` keyword if you want a trait object";
let mut diag =
rustc_errors::struct_span_code_err!(self.dcx(), self_ty.span, E0782, "{}", msg);
let mut diag = rustc_errors::struct_span_code_err!(
self.dcx(),
self_ty.span,
E0782,
"{}",
"expected a type, found a trait"
);
if self_ty.span.can_be_used_for_suggestions()
&& !self.maybe_suggest_impl_trait(self_ty, &mut diag)
&& !self.maybe_suggest_dyn_trait(self_ty, label, sugg, &mut diag)
&& !self.maybe_suggest_dyn_trait(self_ty, sugg, &mut diag)
{
self.maybe_suggest_add_generic_impl_trait(self_ty, &mut diag);
}
@ -131,8 +134,6 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
diag: &mut Diag<'_>,
) -> bool {
let tcx = self.tcx();
let msg = "you might be missing a type parameter";
let mut sugg = vec![];
let parent_hir_id = tcx.parent_hir_id(self_ty.hir_id);
let parent_item = tcx.hir_get_parent_item(self_ty.hir_id).def_id;
@ -160,13 +161,27 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
_ => return false,
};
// FIXME: `T` may already be taken.
sugg.push((
generics.where_clause_span,
format!("<T: {}>", self.tcx().sess.source_map().span_to_snippet(self_ty.span).unwrap()),
));
sugg.push((self_ty.span, "T".to_string()));
diag.multipart_suggestion_verbose(msg, sugg, Applicability::MachineApplicable);
let Ok(rendered_ty) = tcx.sess.source_map().span_to_snippet(self_ty.span) else {
return false;
};
let param = "TUV"
.chars()
.map(|c| c.to_string())
.chain((0..).map(|i| format!("P{i}")))
.find(|s| !generics.params.iter().any(|param| param.name.ident().as_str() == s))
.expect("we definitely can find at least one param name to generate");
let mut sugg = vec![(self_ty.span, param.to_string())];
if let Some(insertion_span) = generics.span_for_param_suggestion() {
sugg.push((insertion_span, format!(", {param}: {}", rendered_ty)));
} else {
sugg.push((generics.where_clause_span, format!("<{param}: {}>", rendered_ty)));
}
diag.multipart_suggestion_verbose(
"you might be missing a type parameter",
sugg,
Applicability::MachineApplicable,
);
true
}
/// Make sure that we are in the condition to suggest the blanket implementation.
@ -227,7 +242,6 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
fn maybe_suggest_dyn_trait(
&self,
self_ty: &hir::Ty<'_>,
label: &str,
sugg: Vec<(Span, String)>,
diag: &mut Diag<'_>,
) -> bool {
@ -270,7 +284,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
// FIXME: Only emit this suggestion if the trait is dyn-compatible.
diag.multipart_suggestion_verbose(
label.to_string(),
"you can add the `dyn` keyword if you want a trait object",
sugg,
Applicability::MachineApplicable,
);