diff --git a/src/librustc/traits/error_reporting/suggestions.rs b/src/librustc/traits/error_reporting/suggestions.rs index 0a9747b631e..c2f562b4bc7 100644 --- a/src/librustc/traits/error_reporting/suggestions.rs +++ b/src/librustc/traits/error_reporting/suggestions.rs @@ -624,12 +624,9 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> { } else { // We still want to verify whether all the return types conform to each other. for expr in &visitor.0 { - if let Some(returned_ty) = tables.node_type_opt(expr.hir_id) { - if let Some(ty) = last_ty { - all_returns_have_same_type &= ty == returned_ty; - } - last_ty = Some(returned_ty); - } + let returned_ty = tables.node_type_opt(expr.hir_id); + all_returns_have_same_type &= last_ty == returned_ty || last_ty.is_none(); + last_ty = returned_ty; } } diff --git a/src/librustc_typeck/check/coercion.rs b/src/librustc_typeck/check/coercion.rs index 66499b1753f..8aa2cb50342 100644 --- a/src/librustc_typeck/check/coercion.rs +++ b/src/librustc_typeck/check/coercion.rs @@ -1372,6 +1372,7 @@ impl<'tcx, 'exprs, E: AsCoercionSite> CoerceMany<'tcx, 'exprs, E> { &snippet[5..] )); } + err.help("alternatively, create a new `enum` with a variant for each returned type"); let impl_trait_msg = "for information on `impl Trait`, see \ "; diff --git a/src/test/ui/impl-trait/equality.stderr b/src/test/ui/impl-trait/equality.stderr index be8653d1689..ceb32dd4cd3 100644 --- a/src/test/ui/impl-trait/equality.stderr +++ b/src/test/ui/impl-trait/equality.stderr @@ -12,6 +12,7 @@ LL | 0_u32 | = note: to return `impl Trait`, all returned values must be of the same type = help: you can instead return a trait object using `Box` + = help: alternatively, create a new `enum` with a variant for each returned type = note: for information on `impl Trait`, see = note: for information on trait objects, see diff --git a/src/test/ui/point-to-type-err-cause-on-impl-trait-return.stderr b/src/test/ui/point-to-type-err-cause-on-impl-trait-return.stderr index 2c0425e718a..87daab5ca7a 100644 --- a/src/test/ui/point-to-type-err-cause-on-impl-trait-return.stderr +++ b/src/test/ui/point-to-type-err-cause-on-impl-trait-return.stderr @@ -12,6 +12,7 @@ LL | 1u32 | = note: to return `impl Trait`, all returned values must be of the same type = help: you can instead return a trait object using `Box` + = help: alternatively, create a new `enum` with a variant for each returned type = note: for information on `impl Trait`, see = note: for information on trait objects, see @@ -29,6 +30,7 @@ LL | return 1u32; | = note: to return `impl Trait`, all returned values must be of the same type = help: you can instead return a trait object using `Box` + = help: alternatively, create a new `enum` with a variant for each returned type = note: for information on `impl Trait`, see = note: for information on trait objects, see @@ -46,6 +48,7 @@ LL | 1u32 | = note: to return `impl Trait`, all returned values must be of the same type = help: you can instead return a trait object using `Box` + = help: alternatively, create a new `enum` with a variant for each returned type = note: for information on `impl Trait`, see = note: for information on trait objects, see @@ -75,6 +78,7 @@ LL | _ => 1u32, | = note: to return `impl Trait`, all returned values must be of the same type = help: you can instead return a trait object using `Box` + = help: alternatively, create a new `enum` with a variant for each returned type = note: for information on `impl Trait`, see = note: for information on trait objects, see @@ -94,6 +98,7 @@ LL | | } | = note: to return `impl Trait`, all returned values must be of the same type = help: you can instead return a trait object using `Box` + = help: alternatively, create a new `enum` with a variant for each returned type = note: for information on `impl Trait`, see = note: for information on trait objects, see @@ -111,6 +116,7 @@ LL | 1u32 | = note: to return `impl Trait`, all returned values must be of the same type = help: you can instead return a trait object using `Box` + = help: alternatively, create a new `enum` with a variant for each returned type = note: for information on `impl Trait`, see = note: for information on trait objects, see