diff options
| -rw-r--r-- | compiler/rustc_builtin_macros/src/deriving/from.rs | 71 | ||||
| -rw-r--r-- | tests/ui/deriving/deriving-from-wrong-target.rs | 2 | ||||
| -rw-r--r-- | tests/ui/deriving/deriving-from-wrong-target.stderr | 42 |
3 files changed, 38 insertions, 77 deletions
diff --git a/compiler/rustc_builtin_macros/src/deriving/from.rs b/compiler/rustc_builtin_macros/src/deriving/from.rs index ef0e6ca324a..ab25de7c917 100644 --- a/compiler/rustc_builtin_macros/src/deriving/from.rs +++ b/compiler/rustc_builtin_macros/src/deriving/from.rs @@ -27,21 +27,39 @@ pub(crate) fn expand_deriving_from( cx.dcx().bug("derive(From) used on something else than an item"); }; - // #[derive(From)] is currently usable only on structs with exactly one field. - let field = if let ItemKind::Struct(_, _, data) = &item.kind - && let [field] = data.fields() - { - Some(field.clone()) - } else { - None + let err_span = || { + let item_span = item.kind.ident().map(|ident| ident.span).unwrap_or(item.span); + MultiSpan::from_spans(vec![span, item_span]) }; - let from_type = match &field { - Some(field) => Ty::AstTy(field.ty.clone()), - // We don't have a type to put into From<...> if we don't have a single field, so just put - // unit there. - None => Ty::Unit, + // `#[derive(From)]` is currently usable only on structs with exactly one field. + let field = match &item.kind { + ItemKind::Struct(_, _, data) => { + if let [field] = data.fields() { + Ok(field.clone()) + } else { + let guar = cx.dcx().emit_err(errors::DeriveFromWrongFieldCount { + span: err_span(), + multiple_fields: data.fields().len() > 1, + }); + Err(guar) + } + } + ItemKind::Enum(_, _, _) | ItemKind::Union(_, _, _) => { + let guar = cx.dcx().emit_err(errors::DeriveFromWrongTarget { + span: err_span(), + kind: &format!("{} {}", item.kind.article(), item.kind.descr()), + }); + Err(guar) + } + _ => cx.dcx().bug("Invalid derive(From) ADT input"), }; + + let from_type = Ty::AstTy(match field { + Ok(ref field) => field.ty.clone(), + Err(guar) => cx.ty(span, ast::TyKind::Err(guar)), + }); + let path = Path::new_(pathvec_std!(convert::From), vec![Box::new(from_type.clone())], PathKind::Std); @@ -71,34 +89,17 @@ pub(crate) fn expand_deriving_from( attributes: thin_vec![cx.attr_word(sym::inline, span)], fieldless_variants_strategy: FieldlessVariantsStrategy::Default, combine_substructure: combine_substructure(Box::new(|cx, span, substructure| { - let Some(field) = &field else { - let item_span = item.kind.ident().map(|ident| ident.span).unwrap_or(item.span); - let err_span = MultiSpan::from_spans(vec![span, item_span]); - let error = match &item.kind { - ItemKind::Struct(_, _, data) => { - cx.dcx().emit_err(errors::DeriveFromWrongFieldCount { - span: err_span, - multiple_fields: data.fields().len() > 1, - }) - } - ItemKind::Enum(_, _, _) | ItemKind::Union(_, _, _) => { - cx.dcx().emit_err(errors::DeriveFromWrongTarget { - span: err_span, - kind: &format!("{} {}", item.kind.article(), item.kind.descr()), - }) - } - _ => cx.dcx().bug("Invalid derive(From) ADT input"), - }; - - return BlockOrExpr::new_expr(DummyResult::raw_expr(span, Some(error))); + let field = match field { + Ok(ref field) => field, + Err(guar) => { + return BlockOrExpr::new_expr(DummyResult::raw_expr(span, Some(guar))); + } }; let self_kw = Ident::new(kw::SelfUpper, span); let expr: Box<ast::Expr> = match substructure.fields { SubstructureFields::StaticStruct(variant, _) => match variant { - // Self { - // field: value - // } + // Self { field: value } VariantData::Struct { .. } => cx.expr_struct_ident( span, self_kw, diff --git a/tests/ui/deriving/deriving-from-wrong-target.rs b/tests/ui/deriving/deriving-from-wrong-target.rs index 37c9300e28b..d0cab937b5d 100644 --- a/tests/ui/deriving/deriving-from-wrong-target.rs +++ b/tests/ui/deriving/deriving-from-wrong-target.rs @@ -29,8 +29,6 @@ struct S4 { enum E1 {} #[derive(From)] -//~^ ERROR the size for values of type `T` cannot be known at compilation time [E0277] -//~| ERROR the size for values of type `T` cannot be known at compilation time [E0277] struct SUnsizedField<T: ?Sized> { last: T, //~^ ERROR the size for values of type `T` cannot be known at compilation time [E0277] diff --git a/tests/ui/deriving/deriving-from-wrong-target.stderr b/tests/ui/deriving/deriving-from-wrong-target.stderr index 63eb8ec7b6e..4547cea5ba6 100644 --- a/tests/ui/deriving/deriving-from-wrong-target.stderr +++ b/tests/ui/deriving/deriving-from-wrong-target.stderr @@ -54,45 +54,7 @@ LL | enum E1 {} = note: `#[derive(From)]` can only be used on structs with exactly one field error[E0277]: the size for values of type `T` cannot be known at compilation time - --> $DIR/deriving-from-wrong-target.rs:31:10 - | -LL | #[derive(From)] - | ^^^^ doesn't have a size known at compile-time -... -LL | struct SUnsizedField<T: ?Sized> { - | - this type parameter needs to be `Sized` - | -note: required by an implicit `Sized` bound in `From` - --> $SRC_DIR/core/src/convert/mod.rs:LL:COL -help: consider removing the `?Sized` bound to make the type parameter `Sized` - | -LL - struct SUnsizedField<T: ?Sized> { -LL + struct SUnsizedField<T> { - | - -error[E0277]: the size for values of type `T` cannot be known at compilation time - --> $DIR/deriving-from-wrong-target.rs:31:10 - | -LL | #[derive(From)] - | ^^^^ doesn't have a size known at compile-time -... -LL | struct SUnsizedField<T: ?Sized> { - | - this type parameter needs to be `Sized` - | -note: required because it appears within the type `SUnsizedField<T>` - --> $DIR/deriving-from-wrong-target.rs:34:8 - | -LL | struct SUnsizedField<T: ?Sized> { - | ^^^^^^^^^^^^^ - = note: the return type of a function must have a statically known size -help: consider removing the `?Sized` bound to make the type parameter `Sized` - | -LL - struct SUnsizedField<T: ?Sized> { -LL + struct SUnsizedField<T> { - | - -error[E0277]: the size for values of type `T` cannot be known at compilation time - --> $DIR/deriving-from-wrong-target.rs:35:11 + --> $DIR/deriving-from-wrong-target.rs:33:11 | LL | struct SUnsizedField<T: ?Sized> { | - this type parameter needs to be `Sized` @@ -110,6 +72,6 @@ help: function arguments must have a statically known size, borrowed types alway LL | last: &T, | + -error: aborting due to 8 previous errors +error: aborting due to 6 previous errors For more information about this error, try `rustc --explain E0277`. |