bjoernager/rust
bjoernager/rust
1
Fork 0
Code Issues Pull requests Activity

only suggest removing semicolon when expr implements trait

Browse source
This commit is contained in:
Michael Goulet 2022-04-07 01:21:35 -07:00
parent 027a232755
commit dfe13dbbcf
15 changed files with 97 additions and 32 deletions
Download patch file Download diff file Expand all files Collapse all files

31
compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
View file

@ -1083,20 +1083,31 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
let parent_node = hir.get_parent_node(obligation.cause.body_id);
let node = hir.find(parent_node);
if let Some(hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn(sig, _, body_id), .. })) = node
&& let body = hir.body(*body_id)
&& let hir::ExprKind::Block(blk, _) = &body.value.kind
&& let hir::ExprKind::Block(blk, _) = &hir.body(*body_id).value.kind
&& sig.decl.output.span().overlaps(span)
&& blk.expr.is_none()
&& *trait_pred.self_ty().skip_binder().kind() == ty::Tuple(ty::List::empty())
// FIXME(estebank): When encountering a method with a trait
// bound not satisfied in the return type with a body that has
// no return, suggest removal of semicolon on last statement.
// Once that is added, close #54771.
&& trait_pred.self_ty().skip_binder().is_unit()
&& let Some(stmt) = blk.stmts.last()
&& let hir::StmtKind::Semi(_) = stmt.kind
&& let hir::StmtKind::Semi(expr) = stmt.kind
// Only suggest this if the expression behind the semicolon implements the predicate
&& let Some(typeck_results) = self.in_progress_typeck_results
&& let Some(ty) = typeck_results.borrow().expr_ty_opt(expr)
&& self.predicate_may_hold(&self.mk_trait_obligation_with_new_self_ty(obligation.param_env, trait_pred, ty))
{
let sp = self.tcx.sess.source_map().end_point(stmt.span);
err.span_label(sp, "consider removing this semicolon");
err.span_label(
expr.span,
&format!(
"this expression has type `{}`, which implements `{}`",
ty,
trait_pred.print_modifiers_and_trait_path()
)
);
err.span_suggestion(
self.tcx.sess.source_map().end_point(stmt.span),
"remove this semicolon",
String::new(),
Applicability::MachineApplicable
);
return true;
}
false