bjoernager/rust
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Implement repr(transparent)

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This commit is contained in:
Robin Kruppe 2018-01-03 17:43:30 +01:00
parent 79a521bb9a
commit 2be697bc21
21 changed files with 881 additions and 12 deletions
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25
src/librustc/hir/check_attr.rs
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@ -92,6 +92,7 @@ impl<'a, 'tcx> CheckAttrVisitor<'a, 'tcx> {
let mut int_reprs = 0;
let mut is_c = false;
let mut is_simd = false;
let mut is_transparent = false;
for hint in &hints {
let name = if let Some(name) = hint.name() {
@ -137,6 +138,14 @@ impl<'a, 'tcx> CheckAttrVisitor<'a, 'tcx> {
continue
}
}
"transparent" => {
is_transparent = true;
if target != Target::Struct {
("a", "struct")
} else {
continue
}
}
"i8" | "u8" | "i16" | "u16" |
"i32" | "u32" | "i64" | "u64" |
"isize" | "usize" => {
@ -155,14 +164,22 @@ impl<'a, 'tcx> CheckAttrVisitor<'a, 'tcx> {
.emit();
}
// Just point at all repr hints if there are any incompatibilities.
// This is not ideal, but tracking precisely which ones are at fault is a huge hassle.
let hint_spans = hints.iter().map(|hint| hint.span);
// Error on repr(transparent, <anything else>).
if is_transparent && hints.len() > 1 {
let hint_spans: Vec<_> = hint_spans.clone().collect();
span_err!(self.tcx.sess, hint_spans, E0692,
"transparent struct cannot have other repr hints");
}
// Warn on repr(u8, u16), repr(C, simd), and c-like-enum-repr(C, u8)
if (int_reprs > 1)
|| (is_simd && is_c)
|| (int_reprs == 1 && is_c && is_c_like_enum(item)) {
// Just point at all repr hints. This is not ideal, but tracking
// precisely which ones are at fault is a huge hassle.
let spans: Vec<_> = hints.iter().map(|hint| hint.span).collect();
span_warn!(self.tcx.sess, spans, E0566,
let hint_spans: Vec<_> = hint_spans.collect();
span_warn!(self.tcx.sess, hint_spans, E0566,
"conflicting representation hints");
}
}