From 0f1da2e2614fd7e81f09a02c76ef52284124460e Mon Sep 17 00:00:00 2001 From: Ruby Lazuli Date: Sat, 9 Jan 2021 12:10:22 -0600 Subject: [PATCH 1/2] Make E0121's suggestion more robust (+ fix E0308's suggestion) Before, both E0308 and E0121 suggested using the unnameable type of a generator as a return type. This fixes this by making Ty::is_suggestable return `false` for generators and by making E0121 use `Ty::is_suggestable` to prevent this from happening in the future. Fixes #80844. --- compiler/rustc_middle/src/ty/diagnostics.rs | 3 ++ compiler/rustc_typeck/src/collect.rs | 55 +++++++++++++-------- src/test/ui/fn/issue-80844-no-gate.rs | 12 +++++ src/test/ui/fn/issue-80844-no-gate.stderr | 19 +++++++ src/test/ui/fn/issue-80844.rs | 15 ++++++ src/test/ui/fn/issue-80844.stderr | 12 +++++ 6 files changed, 96 insertions(+), 20 deletions(-) create mode 100644 src/test/ui/fn/issue-80844-no-gate.rs create mode 100644 src/test/ui/fn/issue-80844-no-gate.stderr create mode 100644 src/test/ui/fn/issue-80844.rs create mode 100644 src/test/ui/fn/issue-80844.stderr diff --git a/compiler/rustc_middle/src/ty/diagnostics.rs b/compiler/rustc_middle/src/ty/diagnostics.rs index f41bb7e6d6350..eabdad2944398 100644 --- a/compiler/rustc_middle/src/ty/diagnostics.rs +++ b/compiler/rustc_middle/src/ty/diagnostics.rs @@ -71,6 +71,9 @@ impl<'tcx> TyS<'tcx> { | Closure(..) | Infer(..) | Projection(..) + | Generator(..) + | GeneratorWitness(..) + | Error(..) ) } } diff --git a/compiler/rustc_typeck/src/collect.rs b/compiler/rustc_typeck/src/collect.rs index a175da3270638..388c80813dd5f 100644 --- a/compiler/rustc_typeck/src/collect.rs +++ b/compiler/rustc_typeck/src/collect.rs @@ -1663,26 +1663,41 @@ fn fn_sig(tcx: TyCtxt<'_>, def_id: DefId) -> ty::PolyFnSig<'_> { let mut diag = bad_placeholder_type(tcx, visitor.0); let ret_ty = fn_sig.output(); if ret_ty != tcx.ty_error() { - if !ret_ty.is_closure() { - let ret_ty_str = match ret_ty.kind() { - // Suggest a function pointer return type instead of a unique function definition - // (e.g. `fn() -> i32` instead of `fn() -> i32 { f }`, the latter of which is invalid - // syntax) - ty::FnDef(..) => ret_ty.fn_sig(tcx).to_string(), - _ => ret_ty.to_string(), - }; - diag.span_suggestion( - ty.span, - "replace with the correct return type", - ret_ty_str, - Applicability::MaybeIncorrect, - ); - } else { - // We're dealing with a closure, so we should suggest using `impl Fn` or trait bounds - // to prevent the user from getting a papercut while trying to use the unique closure - // syntax (e.g. `[closure@src/lib.rs:2:5: 2:9]`). - diag.help("consider using an `Fn`, `FnMut`, or `FnOnce` trait bound"); - diag.note("for more information on `Fn` traits and closure types, see https://doc.rust-lang.org/book/ch13-01-closures.html"); + match ret_ty.kind() { + ty::FnDef(..) => { + diag.span_suggestion( + ty.span, + "replace with the correct return type", + ret_ty.fn_sig(tcx).to_string(), + Applicability::MaybeIncorrect, + ); + } + + ty::Closure(..) => { + diag.help( + "consider using an `Fn`, `FnMut`, or `FnOnce` trait bound", + ); + diag.note("for more information on `Fn` traits and closure types, see https://doc.rust-lang.org/book/ch13-01-closures.html"); + } + + ty::Generator(..) if tcx.features().generators => { + diag.help("consider using a `Generator` trait bound"); + // FIXME: link elsewhere if/when generators are stabilized + diag.note("for more information on generators, see https://doc.rust-lang.org/beta/unstable-book/language-features/generators.html"); + } + + _ if ret_ty.is_suggestable() => { + diag.span_suggestion( + ty.span, + "replace with the correct return type", + ret_ty.to_string(), + // FIXME: should this be MachineApplicable? + // (cf. `rustc_typeck::check::fn_ctxt::suggestions::suggest_missing_return_type()`) + Applicability::MaybeIncorrect, + ); + } + + _ => (), } } diag.emit(); diff --git a/src/test/ui/fn/issue-80844-no-gate.rs b/src/test/ui/fn/issue-80844-no-gate.rs new file mode 100644 index 0000000000000..f54e8e9501ba0 --- /dev/null +++ b/src/test/ui/fn/issue-80844-no-gate.rs @@ -0,0 +1,12 @@ +// Functions with a type placeholder `_` as the return type should +// not suggest anything if generators aren't enabled. + +fn returns_generator() -> _ { +//~^ ERROR the type placeholder `_` is not allowed within types on item signatures [E0121] +//~| NOTE not allowed in type signatures + || yield 0 + //~^ ERROR yield syntax is experimental + //~| NOTE see issue +} + +fn main() {} diff --git a/src/test/ui/fn/issue-80844-no-gate.stderr b/src/test/ui/fn/issue-80844-no-gate.stderr new file mode 100644 index 0000000000000..53e3a061f2946 --- /dev/null +++ b/src/test/ui/fn/issue-80844-no-gate.stderr @@ -0,0 +1,19 @@ +error[E0658]: yield syntax is experimental + --> $DIR/issue-80844-no-gate.rs:7:8 + | +LL | || yield 0 + | ^^^^^^^ + | + = note: see issue #43122 for more information + = help: add `#![feature(generators)]` to the crate attributes to enable + +error[E0121]: the type placeholder `_` is not allowed within types on item signatures + --> $DIR/issue-80844-no-gate.rs:4:27 + | +LL | fn returns_generator() -> _ { + | ^ not allowed in type signatures + +error: aborting due to 2 previous errors + +Some errors have detailed explanations: E0121, E0658. +For more information about an error, try `rustc --explain E0121`. diff --git a/src/test/ui/fn/issue-80844.rs b/src/test/ui/fn/issue-80844.rs new file mode 100644 index 0000000000000..2ae53088ac86a --- /dev/null +++ b/src/test/ui/fn/issue-80844.rs @@ -0,0 +1,15 @@ +#![feature(generators)] + +// Functions with a type placeholder `_` as the return type should +// not suggest returning the unnameable type of generators. +// This is a regression test of #80844 + +fn returns_generator() -> _ { +//~^ ERROR the type placeholder `_` is not allowed within types on item signatures [E0121] +//~| NOTE not allowed in type signatures +//~| HELP consider using a `Generator` trait bound +//~| NOTE for more information on generators + || yield 0 +} + +fn main() {} diff --git a/src/test/ui/fn/issue-80844.stderr b/src/test/ui/fn/issue-80844.stderr new file mode 100644 index 0000000000000..a4ca0eeeaa633 --- /dev/null +++ b/src/test/ui/fn/issue-80844.stderr @@ -0,0 +1,12 @@ +error[E0121]: the type placeholder `_` is not allowed within types on item signatures + --> $DIR/issue-80844.rs:7:27 + | +LL | fn returns_generator() -> _ { + | ^ not allowed in type signatures + | + = help: consider using a `Generator` trait bound + = note: for more information on generators, see https://doc.rust-lang.org/beta/unstable-book/language-features/generators.html + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0121`. From e55aba4512bed37640d196a6adc57e206b9e5951 Mon Sep 17 00:00:00 2001 From: Ruby Lazuli Date: Mon, 11 Jan 2021 22:09:08 -0600 Subject: [PATCH 2/2] Make is_suggestable check recursive --- .../src/infer/error_reporting/mod.rs | 2 +- compiler/rustc_middle/src/ty/diagnostics.rs | 56 ++++++++--- compiler/rustc_typeck/src/astconv/generics.rs | 2 +- .../src/check/fn_ctxt/suggestions.rs | 3 +- compiler/rustc_typeck/src/collect.rs | 4 +- src/test/ui/fn/issue-80844-e0121.rs | 51 ++++++++++ src/test/ui/fn/issue-80844-e0121.stderr | 48 +++++++++ src/test/ui/fn/issue-80844-e0308.rs | 61 ++++++++++++ src/test/ui/fn/issue-80844-e0308.stderr | 97 +++++++++++++++++++ src/test/ui/fn/issue-80844-no-gate.rs | 11 ++- src/test/ui/fn/issue-80844-no-gate.stderr | 8 +- src/test/ui/fn/issue-80844.rs | 15 --- src/test/ui/fn/issue-80844.stderr | 12 --- 13 files changed, 321 insertions(+), 49 deletions(-) create mode 100644 src/test/ui/fn/issue-80844-e0121.rs create mode 100644 src/test/ui/fn/issue-80844-e0121.stderr create mode 100644 src/test/ui/fn/issue-80844-e0308.rs create mode 100644 src/test/ui/fn/issue-80844-e0308.stderr delete mode 100644 src/test/ui/fn/issue-80844.rs delete mode 100644 src/test/ui/fn/issue-80844.stderr diff --git a/compiler/rustc_infer/src/infer/error_reporting/mod.rs b/compiler/rustc_infer/src/infer/error_reporting/mod.rs index eeff48a63950e..6f9c93d17d772 100644 --- a/compiler/rustc_infer/src/infer/error_reporting/mod.rs +++ b/compiler/rustc_infer/src/infer/error_reporting/mod.rs @@ -609,7 +609,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> { match cause.code { ObligationCauseCode::Pattern { origin_expr: true, span: Some(span), root_ty } => { let ty = self.resolve_vars_if_possible(root_ty); - if ty.is_suggestable() { + if ty.is_suggestable(self.tcx) { // don't show type `_` err.span_label(span, format!("this expression has type `{}`", ty)); } diff --git a/compiler/rustc_middle/src/ty/diagnostics.rs b/compiler/rustc_middle/src/ty/diagnostics.rs index eabdad2944398..e5d3731e49b11 100644 --- a/compiler/rustc_middle/src/ty/diagnostics.rs +++ b/compiler/rustc_middle/src/ty/diagnostics.rs @@ -1,7 +1,8 @@ //! Diagnostics related methods for `TyS`. +use crate::ty::subst::SubstsRef; use crate::ty::TyKind::*; -use crate::ty::{InferTy, TyCtxt, TyS}; +use crate::ty::{FnSig, InferTy, PolyFnSig, TyCtxt, TyS, VariantDef}; use rustc_errors::{Applicability, DiagnosticBuilder}; use rustc_hir as hir; use rustc_hir::def_id::DefId; @@ -61,20 +62,45 @@ impl<'tcx> TyS<'tcx> { } /// Whether the type can be safely suggested during error recovery. - pub fn is_suggestable(&self) -> bool { - !matches!( - self.kind(), - Opaque(..) - | FnDef(..) - | FnPtr(..) - | Dynamic(..) - | Closure(..) - | Infer(..) - | Projection(..) - | Generator(..) - | GeneratorWitness(..) - | Error(..) - ) + pub fn is_suggestable(&self, tcx: TyCtxt<'tcx>) -> bool { + debug!("is_suggestable: checking if {:?} is suggestable", self.kind()); + match self.kind() { + Opaque(..) | FnDef(..) | Dynamic(..) | Closure(..) | Infer(..) | Projection(..) + | Generator(..) | GeneratorWitness(..) | Error(..) => false, + + Adt(def, substs) => { + def.variants.iter().all(|variants| variants.is_suggestable(tcx, substs)) + } + + Array(ty, _) | Slice(ty) => ty.is_suggestable(tcx), + FnPtr(sig) => sig.is_suggestable(tcx), + RawPtr(ty_and_mut) => ty_and_mut.ty.is_suggestable(tcx), + Ref(_, ty, _) => ty.is_suggestable(tcx), + Tuple(_) => self.tuple_fields().all(|ty| ty.is_suggestable(tcx)), + + _ => true, + } + } +} + +impl<'tcx> FnSig<'tcx> { + /// Whether this function signature can be safely suggested during error recovery. + pub fn is_suggestable(&self, tcx: TyCtxt<'tcx>) -> bool { + self.inputs_and_output.iter().all(|ty| ty.is_suggestable(tcx)) + } +} + +impl<'tcx> PolyFnSig<'tcx> { + /// Whether this function signature can be safely suggested during error recovery. + pub fn is_suggestable(&self, tcx: TyCtxt<'tcx>) -> bool { + self.as_ref().skip_binder().is_suggestable(tcx) + } +} + +impl VariantDef { + /// Whether this variant can be safely suggested during error recovery. + pub fn is_suggestable<'tcx>(&self, tcx: TyCtxt<'tcx>, substs: SubstsRef<'tcx>) -> bool { + self.fields.iter().all(|field| field.ty(tcx, substs).is_suggestable(tcx)) } } diff --git a/compiler/rustc_typeck/src/astconv/generics.rs b/compiler/rustc_typeck/src/astconv/generics.rs index 0ea0ccaceabd4..c0aa7ad8f379b 100644 --- a/compiler/rustc_typeck/src/astconv/generics.rs +++ b/compiler/rustc_typeck/src/astconv/generics.rs @@ -79,7 +79,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o { let param_hir_id = tcx.hir().local_def_id_to_hir_id(param_local_id); let param_name = tcx.hir().ty_param_name(param_hir_id); let param_type = tcx.type_of(param.def_id); - if param_type.is_suggestable() { + if param_type.is_suggestable(tcx) { err.span_suggestion( tcx.def_span(src_def_id), "consider changing this type paramater to a `const`-generic", diff --git a/compiler/rustc_typeck/src/check/fn_ctxt/suggestions.rs b/compiler/rustc_typeck/src/check/fn_ctxt/suggestions.rs index 9f15993e4718c..7c652ba9f7162 100644 --- a/compiler/rustc_typeck/src/check/fn_ctxt/suggestions.rs +++ b/compiler/rustc_typeck/src/check/fn_ctxt/suggestions.rs @@ -435,7 +435,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { ) -> bool { // Only suggest changing the return type for methods that // haven't set a return type at all (and aren't `fn main()` or an impl). - match (&fn_decl.output, found.is_suggestable(), can_suggest, expected.is_unit()) { + debug!("suggest_missing_return_type: about to determine if {:?} is suggestable", found); + match (&fn_decl.output, found.is_suggestable(self.tcx), can_suggest, expected.is_unit()) { (&hir::FnRetTy::DefaultReturn(span), true, true, true) => { err.span_suggestion( span, diff --git a/compiler/rustc_typeck/src/collect.rs b/compiler/rustc_typeck/src/collect.rs index 388c80813dd5f..ff7b9067b6079 100644 --- a/compiler/rustc_typeck/src/collect.rs +++ b/compiler/rustc_typeck/src/collect.rs @@ -1664,7 +1664,7 @@ fn fn_sig(tcx: TyCtxt<'_>, def_id: DefId) -> ty::PolyFnSig<'_> { let ret_ty = fn_sig.output(); if ret_ty != tcx.ty_error() { match ret_ty.kind() { - ty::FnDef(..) => { + ty::FnDef(..) if ret_ty.fn_sig(tcx).is_suggestable(tcx) => { diag.span_suggestion( ty.span, "replace with the correct return type", @@ -1686,7 +1686,7 @@ fn fn_sig(tcx: TyCtxt<'_>, def_id: DefId) -> ty::PolyFnSig<'_> { diag.note("for more information on generators, see https://doc.rust-lang.org/beta/unstable-book/language-features/generators.html"); } - _ if ret_ty.is_suggestable() => { + _ if ret_ty.is_suggestable(tcx) => { diag.span_suggestion( ty.span, "replace with the correct return type", diff --git a/src/test/ui/fn/issue-80844-e0121.rs b/src/test/ui/fn/issue-80844-e0121.rs new file mode 100644 index 0000000000000..8b9fd16dc4702 --- /dev/null +++ b/src/test/ui/fn/issue-80844-e0121.rs @@ -0,0 +1,51 @@ +#![feature(generators)] + +// Functions with a type placeholder `_` as the return type should +// not suggest returning the unnameable type of generators. +// This is a regression test of #80844 + +struct Container(T); + +fn returns_generator() -> _ { +//~^ ERROR the type placeholder `_` is not allowed within types on item signatures [E0121] +//~| NOTE not allowed in type signatures +//~| HELP consider using a `Generator` trait bound +//~| NOTE for more information on generators + || yield 0i32 +} + +fn returns_returns_generator() -> _ { +//~^ ERROR the type placeholder `_` is not allowed within types on item signatures [E0121] +//~| NOTE not allowed in type signatures + returns_generator +} + +fn returns_option_closure() -> _ { +//~^ ERROR the type placeholder `_` is not allowed within types on item signatures [E0121] +//~| NOTE not allowed in type signatures + Some(|| 0i32) +} + +fn returns_option_i32() -> _ { +//~^ ERROR the type placeholder `_` is not allowed within types on item signatures [E0121] +//~| NOTE not allowed in type signatures +//~| HELP replace with the correct return type +//~| SUGGESTION Option + Some(0i32) +} + +fn returns_container_closure() -> _ { +//~^ ERROR the type placeholder `_` is not allowed within types on item signatures [E0121] +//~| NOTE not allowed in type signatures + Container(|| 0i32) +} + +fn returns_container_i32() -> _ { +//~^ ERROR the type placeholder `_` is not allowed within types on item signatures [E0121] +//~| NOTE not allowed in type signatures +//~| HELP replace with the correct return type +//~| SUGGESTION Container + Container(0i32) +} + +fn main() {} diff --git a/src/test/ui/fn/issue-80844-e0121.stderr b/src/test/ui/fn/issue-80844-e0121.stderr new file mode 100644 index 0000000000000..b17a5e0a6adb0 --- /dev/null +++ b/src/test/ui/fn/issue-80844-e0121.stderr @@ -0,0 +1,48 @@ +error[E0121]: the type placeholder `_` is not allowed within types on item signatures + --> $DIR/issue-80844-e0121.rs:9:27 + | +LL | fn returns_generator() -> _ { + | ^ not allowed in type signatures + | + = help: consider using a `Generator` trait bound + = note: for more information on generators, see https://doc.rust-lang.org/beta/unstable-book/language-features/generators.html + +error[E0121]: the type placeholder `_` is not allowed within types on item signatures + --> $DIR/issue-80844-e0121.rs:17:35 + | +LL | fn returns_returns_generator() -> _ { + | ^ not allowed in type signatures + +error[E0121]: the type placeholder `_` is not allowed within types on item signatures + --> $DIR/issue-80844-e0121.rs:23:32 + | +LL | fn returns_option_closure() -> _ { + | ^ not allowed in type signatures + +error[E0121]: the type placeholder `_` is not allowed within types on item signatures + --> $DIR/issue-80844-e0121.rs:29:28 + | +LL | fn returns_option_i32() -> _ { + | ^ + | | + | not allowed in type signatures + | help: replace with the correct return type: `Option` + +error[E0121]: the type placeholder `_` is not allowed within types on item signatures + --> $DIR/issue-80844-e0121.rs:37:35 + | +LL | fn returns_container_closure() -> _ { + | ^ not allowed in type signatures + +error[E0121]: the type placeholder `_` is not allowed within types on item signatures + --> $DIR/issue-80844-e0121.rs:43:31 + | +LL | fn returns_container_i32() -> _ { + | ^ + | | + | not allowed in type signatures + | help: replace with the correct return type: `Container` + +error: aborting due to 6 previous errors + +For more information about this error, try `rustc --explain E0121`. diff --git a/src/test/ui/fn/issue-80844-e0308.rs b/src/test/ui/fn/issue-80844-e0308.rs new file mode 100644 index 0000000000000..7994206bea073 --- /dev/null +++ b/src/test/ui/fn/issue-80844-e0308.rs @@ -0,0 +1,61 @@ +#![feature(generators)] + +// Functions with a type placeholder `_` as the return type should +// not suggest returning the unnameable type of generators. +// This is a regression test of #80844 + +struct Container(T); + +fn expected_unit_got_generator() { +//~^ NOTE possibly return type missing here? + || yield 0i32 + //~^ ERROR mismatched types [E0308] + //~| NOTE expected unit type `()` + //~| NOTE expected `()`, found generator +} + +fn expected_unit_got_closure() { +//~^ NOTE possibly return type missing here? + || 0i32 + //~^ ERROR mismatched types [E0308] + //~| NOTE expected unit type `()` + //~| NOTE expected `()`, found closure +} + +fn expected_unit_got_option_closure() { +//~^ NOTE possibly return type missing here? + Some(|| 0i32) + //~^ ERROR mismatched types [E0308] + //~| NOTE expected unit type `()` + //~| NOTE expected `()`, found enum `Option` + //~| HELP try adding a semicolon +} + +fn expected_unit_got_option_i32() { +//~^ NOTE possibly return type missing here? + Some(0i32) + //~^ ERROR mismatched types [E0308] + //~| NOTE expected unit type `()` + //~| NOTE expected `()`, found enum `Option` + //~| HELP try adding a semicolon +} + +fn expected_unit_got_container_closure() { +//~^ NOTE possibly return type missing here? + Container(|| 0i32) + //~^ ERROR mismatched types [E0308] + //~| NOTE expected unit type `()` + //~| NOTE expected `()`, found struct `Container` + //~| HELP try adding a semicolon +} + +fn expected_unit_got_container_i32() { +//~^ NOTE possibly return type missing here? + Container(0i32) + //~^ ERROR mismatched types [E0308] + //~| NOTE expected unit type `()` + //~| NOTE expected `()`, found struct `Container` + //~| HELP try adding a semicolon +} + +fn main() {} diff --git a/src/test/ui/fn/issue-80844-e0308.stderr b/src/test/ui/fn/issue-80844-e0308.stderr new file mode 100644 index 0000000000000..15b5ee486f130 --- /dev/null +++ b/src/test/ui/fn/issue-80844-e0308.stderr @@ -0,0 +1,97 @@ +error[E0308]: mismatched types + --> $DIR/issue-80844-e0308.rs:11:5 + | +LL | fn expected_unit_got_generator() { + | - possibly return type missing here? +LL | +LL | || yield 0i32 + | ^^^^^^^^^^^^^ expected `()`, found generator + | + = note: expected unit type `()` + found generator `[generator@$DIR/issue-80844-e0308.rs:11:5: 11:18]` + +error[E0308]: mismatched types + --> $DIR/issue-80844-e0308.rs:19:5 + | +LL | fn expected_unit_got_closure() { + | - possibly return type missing here? +LL | +LL | || 0i32 + | ^^^^^^^ expected `()`, found closure + | + = note: expected unit type `()` + found closure `[closure@$DIR/issue-80844-e0308.rs:19:5: 19:12]` + +error[E0308]: mismatched types + --> $DIR/issue-80844-e0308.rs:27:5 + | +LL | fn expected_unit_got_option_closure() { + | - possibly return type missing here? +LL | +LL | Some(|| 0i32) + | ^^^^^^^^^^^^^- help: try adding a semicolon: `;` + | | + | expected `()`, found enum `Option` + | + = note: expected unit type `()` + found enum `Option<[closure@$DIR/issue-80844-e0308.rs:27:10: 27:17]>` + +error[E0308]: mismatched types + --> $DIR/issue-80844-e0308.rs:36:5 + | +LL | fn expected_unit_got_option_i32() { + | - possibly return type missing here? +LL | +LL | Some(0i32) + | ^^^^^^^^^^- help: try adding a semicolon: `;` + | | + | expected `()`, found enum `Option` + | + = note: expected unit type `()` + found enum `Option` + +error[E0308]: mismatched types + --> $DIR/issue-80844-e0308.rs:45:5 + | +LL | fn expected_unit_got_container_closure() { + | - possibly return type missing here? +LL | +LL | Container(|| 0i32) + | ^^^^^^^^^^^^^^^^^^- help: try adding a semicolon: `;` + | | + | expected `()`, found struct `Container` + | + = note: expected unit type `()` + found struct `Container<[closure@$DIR/issue-80844-e0308.rs:45:15: 45:22]>` + +error[E0308]: mismatched types + --> $DIR/issue-80844-e0308.rs:54:5 + | +LL | fn expected_unit_got_container_i32() { + | - possibly return type missing here? +LL | +LL | Container(0i32) + | ^^^^^^^^^^^^^^^- help: try adding a semicolon: `;` + | | + | expected `()`, found struct `Container` + | + = note: expected unit type `()` + found struct `Container` + +error[E0308]: mismatched types + --> $DIR/issue-80844-e0308.rs:63:5 + | +LL | fn expected_unit_got_container_bool() { + | - possibly return type missing here? +LL | +LL | Container(true) + | ^^^^^^^^^^^^^^^- help: try adding a semicolon: `;` + | | + | expected `()`, found struct `Container` + | + = note: expected unit type `()` + found struct `Container` + +error: aborting due to 7 previous errors + +For more information about this error, try `rustc --explain E0308`. diff --git a/src/test/ui/fn/issue-80844-no-gate.rs b/src/test/ui/fn/issue-80844-no-gate.rs index f54e8e9501ba0..8bc1ef3731d48 100644 --- a/src/test/ui/fn/issue-80844-no-gate.rs +++ b/src/test/ui/fn/issue-80844-no-gate.rs @@ -1,5 +1,5 @@ // Functions with a type placeholder `_` as the return type should -// not suggest anything if generators aren't enabled. +// not suggest using a `Generator` bound if generators aren't enabled. fn returns_generator() -> _ { //~^ ERROR the type placeholder `_` is not allowed within types on item signatures [E0121] @@ -9,4 +9,13 @@ fn returns_generator() -> _ { //~| NOTE see issue } +fn returns_returns_generator() -> _ { +//~^ ERROR the type placeholder `_` is not allowed within types on item signatures [E0121] +//~| NOTE not allowed in type signatures + returns_generator +} + +// Emitting diagnostics for closures without the `generators` feature gate +// is tested by `issue-80179.rs`. + fn main() {} diff --git a/src/test/ui/fn/issue-80844-no-gate.stderr b/src/test/ui/fn/issue-80844-no-gate.stderr index 53e3a061f2946..056a22a5cee7c 100644 --- a/src/test/ui/fn/issue-80844-no-gate.stderr +++ b/src/test/ui/fn/issue-80844-no-gate.stderr @@ -13,7 +13,13 @@ error[E0121]: the type placeholder `_` is not allowed within types on item signa LL | fn returns_generator() -> _ { | ^ not allowed in type signatures -error: aborting due to 2 previous errors +error[E0121]: the type placeholder `_` is not allowed within types on item signatures + --> $DIR/issue-80844-no-gate.rs:12:35 + | +LL | fn returns_returns_generator() -> _ { + | ^ not allowed in type signatures + +error: aborting due to 3 previous errors Some errors have detailed explanations: E0121, E0658. For more information about an error, try `rustc --explain E0121`. diff --git a/src/test/ui/fn/issue-80844.rs b/src/test/ui/fn/issue-80844.rs deleted file mode 100644 index 2ae53088ac86a..0000000000000 --- a/src/test/ui/fn/issue-80844.rs +++ /dev/null @@ -1,15 +0,0 @@ -#![feature(generators)] - -// Functions with a type placeholder `_` as the return type should -// not suggest returning the unnameable type of generators. -// This is a regression test of #80844 - -fn returns_generator() -> _ { -//~^ ERROR the type placeholder `_` is not allowed within types on item signatures [E0121] -//~| NOTE not allowed in type signatures -//~| HELP consider using a `Generator` trait bound -//~| NOTE for more information on generators - || yield 0 -} - -fn main() {} diff --git a/src/test/ui/fn/issue-80844.stderr b/src/test/ui/fn/issue-80844.stderr deleted file mode 100644 index a4ca0eeeaa633..0000000000000 --- a/src/test/ui/fn/issue-80844.stderr +++ /dev/null @@ -1,12 +0,0 @@ -error[E0121]: the type placeholder `_` is not allowed within types on item signatures - --> $DIR/issue-80844.rs:7:27 - | -LL | fn returns_generator() -> _ { - | ^ not allowed in type signatures - | - = help: consider using a `Generator` trait bound - = note: for more information on generators, see https://doc.rust-lang.org/beta/unstable-book/language-features/generators.html - -error: aborting due to previous error - -For more information about this error, try `rustc --explain E0121`.