diff options
4 files changed, 111 insertions, 7 deletions
diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs index d0f76f0d50e..a962be54c3d 100644 --- a/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs +++ b/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs @@ -4610,6 +4610,9 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> { }) } + // For E0277 when use `?` operator, suggest adding + // a suitable return type in `FnSig`, and a default + // return value at the end of the function's body. pub(super) fn suggest_add_result_as_return_type( &self, obligation: &PredicateObligation<'tcx>, @@ -4620,19 +4623,47 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> { return; } + // Only suggest for local function and associated method, + // because this suggest adding both return type in + // the `FnSig` and a default return value in the body, so it + // is not suitable for foreign function without a local body, + // and neighter for trait method which may be also implemented + // in other place, so shouldn't change it's FnSig. + fn choose_suggest_items<'tcx, 'hir>( + tcx: TyCtxt<'tcx>, + node: hir::Node<'hir>, + ) -> Option<(&'hir hir::FnDecl<'hir>, hir::BodyId)> { + match node { + hir::Node::Item(item) if let hir::ItemKind::Fn(sig, _, body_id) = item.kind => { + Some((sig.decl, body_id)) + } + hir::Node::ImplItem(item) + if let hir::ImplItemKind::Fn(sig, body_id) = item.kind => + { + let parent = tcx.parent_hir_node(item.hir_id()); + if let hir::Node::Item(item) = parent + && let hir::ItemKind::Impl(imp) = item.kind + && imp.of_trait.is_none() + { + return Some((sig.decl, body_id)); + } + None + } + _ => None, + } + } + let node = self.tcx.hir_node_by_def_id(obligation.cause.body_id); - if let hir::Node::Item(item) = node - && let hir::ItemKind::Fn(sig, _, body_id) = item.kind - && let hir::FnRetTy::DefaultReturn(ret_span) = sig.decl.output + if let Some((fn_decl, body_id)) = choose_suggest_items(self.tcx, node) + && let hir::FnRetTy::DefaultReturn(ret_span) = fn_decl.output && self.tcx.is_diagnostic_item(sym::FromResidual, trait_pred.def_id()) && trait_pred.skip_binder().trait_ref.args.type_at(0).is_unit() && let ty::Adt(def, _) = trait_pred.skip_binder().trait_ref.args.type_at(1).kind() && self.tcx.is_diagnostic_item(sym::Result, def.did()) { - let body = self.tcx.hir().body(body_id); let mut sugg_spans = vec![(ret_span, " -> Result<(), Box<dyn std::error::Error>>".to_string())]; - + let body = self.tcx.hir().body(body_id); if let hir::ExprKind::Block(b, _) = body.value.kind && b.expr.is_none() { diff --git a/tests/ui/return/return-from-residual-sugg-issue-125997.fixed b/tests/ui/return/return-from-residual-sugg-issue-125997.fixed index b2eca69aeb9..a5a13399825 100644 --- a/tests/ui/return/return-from-residual-sugg-issue-125997.fixed +++ b/tests/ui/return/return-from-residual-sugg-issue-125997.fixed @@ -33,6 +33,25 @@ macro_rules! mac { }; } +struct A; + +impl A { + fn test4(&self) -> Result<(), Box<dyn std::error::Error>> { + let mut _file = File::create("foo.txt")?; + //~^ ERROR the `?` operator can only be used in a method + + Ok(()) +} + + fn test5(&self) -> Result<(), Box<dyn std::error::Error>> { + let mut _file = File::create("foo.txt")?; + //~^ ERROR the `?` operator can only be used in a method + println!(); + + Ok(()) +} +} + fn main() -> Result<(), Box<dyn std::error::Error>> { let mut _file = File::create("foo.txt")?; //~^ ERROR the `?` operator can only be used in a function diff --git a/tests/ui/return/return-from-residual-sugg-issue-125997.rs b/tests/ui/return/return-from-residual-sugg-issue-125997.rs index dd8550a388b..30ca27eae45 100644 --- a/tests/ui/return/return-from-residual-sugg-issue-125997.rs +++ b/tests/ui/return/return-from-residual-sugg-issue-125997.rs @@ -27,6 +27,21 @@ macro_rules! mac { }; } +struct A; + +impl A { + fn test4(&self) { + let mut _file = File::create("foo.txt")?; + //~^ ERROR the `?` operator can only be used in a method + } + + fn test5(&self) { + let mut _file = File::create("foo.txt")?; + //~^ ERROR the `?` operator can only be used in a method + println!(); + } +} + fn main() { let mut _file = File::create("foo.txt")?; //~^ ERROR the `?` operator can only be used in a function diff --git a/tests/ui/return/return-from-residual-sugg-issue-125997.stderr b/tests/ui/return/return-from-residual-sugg-issue-125997.stderr index ef938f0213d..a59f38c2ec6 100644 --- a/tests/ui/return/return-from-residual-sugg-issue-125997.stderr +++ b/tests/ui/return/return-from-residual-sugg-issue-125997.stderr @@ -37,8 +37,47 @@ LL + Ok(()) LL + } | +error[E0277]: the `?` operator can only be used in a method that returns `Result` or `Option` (or another type that implements `FromResidual`) + --> $DIR/return-from-residual-sugg-issue-125997.rs:34:48 + | +LL | fn test4(&self) { + | --------------- this function should return `Result` or `Option` to accept `?` +LL | let mut _file = File::create("foo.txt")?; + | ^ cannot use the `?` operator in a method that returns `()` + | + = help: the trait `FromResidual<Result<Infallible, std::io::Error>>` is not implemented for `()` +help: consider adding return type + | +LL ~ fn test4(&self) -> Result<(), Box<dyn std::error::Error>> { +LL | let mut _file = File::create("foo.txt")?; +LL | +LL ~ +LL + Ok(()) +LL + } + | + +error[E0277]: the `?` operator can only be used in a method that returns `Result` or `Option` (or another type that implements `FromResidual`) + --> $DIR/return-from-residual-sugg-issue-125997.rs:39:48 + | +LL | fn test5(&self) { + | --------------- this function should return `Result` or `Option` to accept `?` +LL | let mut _file = File::create("foo.txt")?; + | ^ cannot use the `?` operator in a method that returns `()` + | + = help: the trait `FromResidual<Result<Infallible, std::io::Error>>` is not implemented for `()` +help: consider adding return type + | +LL ~ fn test5(&self) -> Result<(), Box<dyn std::error::Error>> { +LL | let mut _file = File::create("foo.txt")?; +LL | +LL | println!(); +LL ~ +LL + Ok(()) +LL + } + | + error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`) - --> $DIR/return-from-residual-sugg-issue-125997.rs:31:44 + --> $DIR/return-from-residual-sugg-issue-125997.rs:46:44 | LL | fn main() { | --------- this function should return `Result` or `Option` to accept `?` @@ -81,6 +120,6 @@ LL + Ok(()) LL + } | -error: aborting due to 4 previous errors +error: aborting due to 6 previous errors For more information about this error, try `rustc --explain E0277`. |