Right now you just have to hope that whoever adds a new option to CodegenFnAttrFlags correctly updates all the places where it is relevant, e.g.
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let mut attrs = Cow::Borrowed(self.codegen_fn_attrs(instance_kind.def_id())); |
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|
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// Drop the `#[naked]` attribute on non-item `InstanceKind`s, like the shims that |
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// are generated for indirect function calls. |
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if !matches!(instance_kind, InstanceKind::Item(_)) { |
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if attrs.flags.contains(CodegenFnAttrFlags::NAKED) { |
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attrs.to_mut().flags.remove(CodegenFnAttrFlags::NAKED); |
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} |
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} |
|
|
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// A shim created by `#[track_caller]` should not inherit any attributes |
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// that modify the symbol name. Failing to remove these attributes from |
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// the shim leads to errors like `symbol `foo` is already defined`. |
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// |
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// A `ClosureOnceShim` with the track_caller attribute does not have a symbol, |
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// and therefore can be skipped here. |
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if let InstanceKind::ReifyShim(_, _) = instance_kind |
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&& attrs.flags.contains(CodegenFnAttrFlags::TRACK_CALLER) |
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{ |
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if attrs.flags.contains(CodegenFnAttrFlags::NO_MANGLE) { |
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attrs.to_mut().flags.remove(CodegenFnAttrFlags::NO_MANGLE); |
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} |
|
|
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if attrs.flags.contains(CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL) { |
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attrs.to_mut().flags.remove(CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL); |
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} |
|
|
|
if attrs.symbol_name.is_some() { |
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attrs.to_mut().symbol_name = None; |
|
} |
|
} |
|
|
|
attrs |
cc @jdonszelmann #146348
This is quite fragile and I certainly wouldn't have caught this omission in review.
A way to prevent such bugs is by exhaustively matching on all options in such places, e.g.
|
let (ty::FloatTy::F16 | ty::FloatTy::F32 | ty::FloatTy::F64 | ty::FloatTy::F128); |
|
let possible_floats = [ |
|
ty::SimplifiedType::Float(ty::FloatTy::F16), |
|
ty::SimplifiedType::Float(ty::FloatTy::F32), |
|
ty::SimplifiedType::Float(ty::FloatTy::F64), |
|
ty::SimplifiedType::Float(ty::FloatTy::F128), |
|
]; |
|
fn has_only_region_constraints<I: Interner>(response: ty::Canonical<I, Response<I>>) -> bool { |
|
let ExternalConstraintsData { |
|
region_constraints: _, |
|
ref opaque_types, |
|
ref normalization_nested_goals, |
|
} = *response.value.external_constraints; |
|
response.value.var_values.is_identity_modulo_regions() |
|
&& opaque_types.is_empty() |
|
&& normalization_nested_goals.is_empty() |
|
} |
Imo we should extend our bitflags macro to also emit an enum of all options to enable us to exhaustively match on them in cases where this is likely useful.
