Check all repr hints together when checking for mis-applied attributes
Fixes #47094 Besides fixing that bug, this change has a user-visible effect on the spans in the "incompatible repr hints" warning and another error: they now point at `foo` and/or `bar` in `repr(foo, bar)` instead of the whole attribute. This is sometimes more precise (e.g., `#[repr(C, packed)]` on an enum points at the `packed`) but sometimes not. I moved a compile-fail test to a ui test to illustrate how it now looks in the common case of only one attribute.
This commit is contained in:
Robin Kruppe
parent
00fbfcce96
commit
03936115ef
@ -47,14 +47,15 @@ struct CheckAttrVisitor<'a> {
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impl<'a> CheckAttrVisitor<'a> {
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/// Check any attribute.
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fn check_attribute(&self, attr: &ast::Attribute, item: &ast::Item, target: Target) {
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if let Some(name) = attr.name() {
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match &*name.as_str() {
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"inline" => self.check_inline(attr, item, target),
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"repr" => self.check_repr(attr, item, target),
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_ => (),
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fn check_attributes(&self, item: &ast::Item, target: Target) {
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for attr in &item.attrs {
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if let Some(name) = attr.name() {
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if name == "inline" {
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self.check_inline(attr, item, target)
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}
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}
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}
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self.check_repr(item, target);
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}
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/// Check if an `#[inline]` is applied to a function.
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@ -66,45 +67,51 @@ impl<'a> CheckAttrVisitor<'a> {
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}
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}
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/// Check if an `#[repr]` attr is valid.
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fn check_repr(&self, attr: &ast::Attribute, item: &ast::Item, target: Target) {
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let words = match attr.meta_item_list() {
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Some(words) => words,
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None => {
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return;
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}
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};
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/// Check if the `#[repr]` attributes on `item` are valid.
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fn check_repr(&self, item: &ast::Item, target: Target) {
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// Extract the names of all repr hints, e.g., [foo, bar, align] for:
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// ```
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// #[repr(foo)]
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// #[repr(bar, align(8))]
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// ```
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let hints: Vec<_> = item.attrs
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.iter()
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.filter(|attr| match attr.name() {
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Some(name) => name == "repr",
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None => false,
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})
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.filter_map(|attr| attr.meta_item_list())
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.flat_map(|hints| hints)
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.collect();
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let mut int_reprs = 0;
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let mut is_c = false;
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let mut is_simd = false;
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for word in words {
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let name = match word.name() {
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Some(word) => word,
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None => continue,
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for hint in &hints {
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let name = if let Some(name) = hint.name() {
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name
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} else {
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// Invalid repr hint like repr(42). We don't check for unrecognized hints here
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// (libsyntax does that), so just ignore it.
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continue;
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};
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let (message, label) = match &*name.as_str() {
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let (article, allowed_targets) = match &*name.as_str() {
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"C" => {
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is_c = true;
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if target != Target::Struct &&
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target != Target::Union &&
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target != Target::Enum {
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("attribute should be applied to struct, enum or union",
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"a struct, enum or union")
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("a", "struct, enum or union")
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} else {
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continue
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}
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}
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"packed" => {
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// Do not increment conflicting_reprs here, because "packed"
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// can be used to modify another repr hint
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if target != Target::Struct &&
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target != Target::Union {
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("attribute should be applied to struct or union",
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"a struct or union")
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("a", "struct or union")
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} else {
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continue
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}
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@ -112,8 +119,7 @@ impl<'a> CheckAttrVisitor<'a> {
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"simd" => {
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is_simd = true;
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if target != Target::Struct {
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("attribute should be applied to struct",
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"a struct")
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("a", "struct")
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} else {
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continue
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}
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@ -121,8 +127,7 @@ impl<'a> CheckAttrVisitor<'a> {
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"align" => {
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if target != Target::Struct &&
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target != Target::Union {
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("attribute should be applied to struct or union",
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"a struct or union")
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("a", "struct or union")
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} else {
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continue
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}
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@ -132,16 +137,16 @@ impl<'a> CheckAttrVisitor<'a> {
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"isize" | "usize" => {
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int_reprs += 1;
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if target != Target::Enum {
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("attribute should be applied to enum",
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"an enum")
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("an", "enum")
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} else {
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continue
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}
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}
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_ => continue,
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};
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struct_span_err!(self.sess, attr.span, E0517, "{}", message)
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.span_label(item.span, format!("not {}", label))
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struct_span_err!(self.sess, hint.span, E0517,
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"attribute should be applied to {}", allowed_targets)
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.span_label(item.span, format!("not {} {}", article, allowed_targets))
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.emit();
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}
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@ -149,7 +154,10 @@ impl<'a> CheckAttrVisitor<'a> {
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if (int_reprs > 1)
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|| (is_simd && is_c)
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|| (int_reprs == 1 && is_c && is_c_like_enum(item)) {
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span_warn!(self.sess, attr.span, E0566,
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// Just point at all repr hints. This is not ideal, but tracking precisely which ones
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// are at fault is a huge hassle.
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let spans: Vec<_> = hints.iter().map(|hint| hint.span).collect();
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span_warn!(self.sess, spans, E0566,
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"conflicting representation hints");
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}
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}
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@ -158,9 +166,7 @@ impl<'a> CheckAttrVisitor<'a> {
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impl<'a> Visitor<'a> for CheckAttrVisitor<'a> {
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fn visit_item(&mut self, item: &'a ast::Item) {
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let target = Target::from_item(item);
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for attr in &item.attrs {
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self.check_attribute(attr, item, target);
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}
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self.check_attributes(item, target);
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visit::walk_item(self, item);
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}
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}
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@ -8,7 +8,6 @@
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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#![allow(dead_code)]
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#![feature(attr_literals)]
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#![feature(repr_simd)]
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42
src/test/ui/attr-usage-repr.stderr
Normal file
42
src/test/ui/attr-usage-repr.stderr
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@ -0,0 +1,42 @@
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error[E0517]: attribute should be applied to struct, enum or union
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--> $DIR/attr-usage-repr.rs:14:8
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14 | #[repr(C)] //~ ERROR: attribute should be applied to struct, enum or union
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| ^
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15 | fn f() {}
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| --------- not a struct, enum or union
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error[E0517]: attribute should be applied to enum
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--> $DIR/attr-usage-repr.rs:26:8
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26 | #[repr(i8)] //~ ERROR: attribute should be applied to enum
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| ^^
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27 | struct SInt(f64, f64);
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| ---------------------- not an enum
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error[E0517]: attribute should be applied to struct or union
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--> $DIR/attr-usage-repr.rs:32:8
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32 | #[repr(align(8))] //~ ERROR: attribute should be applied to struct
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| ^^^^^^^^
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33 | enum EAlign { A, B }
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| -------------------- not a struct or union
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error[E0517]: attribute should be applied to struct or union
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--> $DIR/attr-usage-repr.rs:35:8
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35 | #[repr(packed)] //~ ERROR: attribute should be applied to struct
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| ^^^^^^
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36 | enum EPacked { A, B }
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| --------------------- not a struct or union
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error[E0517]: attribute should be applied to struct
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--> $DIR/attr-usage-repr.rs:38:8
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38 | #[repr(simd)] //~ ERROR: attribute should be applied to struct
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| ^^^^
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39 | enum ESimd { A, B }
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| ------------------- not a struct
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error: aborting due to 5 previous errors
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@ -13,7 +13,6 @@
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#[repr(simd)]
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#[derive(Copy, Clone)]
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#[repr(C)]
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struct LocalSimd(u8, u8);
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extern {
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@ -1,15 +1,15 @@
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error: use of SIMD type `LocalSimd` in FFI is highly experimental and may result in invalid code
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--> $DIR/feature-gate-simd-ffi.rs:20:17
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--> $DIR/feature-gate-simd-ffi.rs:19:17
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20 | fn baz() -> LocalSimd; //~ ERROR use of SIMD type
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19 | fn baz() -> LocalSimd; //~ ERROR use of SIMD type
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| ^^^^^^^^^
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= help: add #![feature(simd_ffi)] to the crate attributes to enable
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error: use of SIMD type `LocalSimd` in FFI is highly experimental and may result in invalid code
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--> $DIR/feature-gate-simd-ffi.rs:21:15
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--> $DIR/feature-gate-simd-ffi.rs:20:15
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21 | fn qux(x: LocalSimd); //~ ERROR use of SIMD type
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20 | fn qux(x: LocalSimd); //~ ERROR use of SIMD type
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| ^^^^^^^^^
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= help: add #![feature(simd_ffi)] to the crate attributes to enable
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26
src/test/ui/issue-47094.rs
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26
src/test/ui/issue-47094.rs
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@ -0,0 +1,26 @@
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// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// must-compile-successfully
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#[repr(C,u8)]
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enum Foo {
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A,
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B,
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}
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#[repr(C)]
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#[repr(u8)]
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enum Bar {
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A,
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B,
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}
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fn main() {}
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14
src/test/ui/issue-47094.stderr
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14
src/test/ui/issue-47094.stderr
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@ -0,0 +1,14 @@
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warning[E0566]: conflicting representation hints
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--> $DIR/issue-47094.rs:13:8
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13 | #[repr(C,u8)]
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| ^ ^^
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warning[E0566]: conflicting representation hints
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--> $DIR/issue-47094.rs:19:8
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19 | #[repr(C)]
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| ^
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20 | #[repr(u8)]
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| ^^
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