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Lint on function pointers used in patterns

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This commit is contained in:
Oliver Scherer 2020-09-20 17:11:00 +02:00
parent 3795886f7e
commit aba5ea1430
6 changed files with 97 additions and 3 deletions
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19
compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs
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@ -351,10 +351,27 @@ impl<'a, 'tcx> ConstToPat<'a, 'tcx> {
ty::Bool | ty::Char | ty::Int(_) | ty::Uint(_) | ty::FnDef(..) => {
PatKind::Constant { value: cv }
}
ty::RawPtr(pointee) if pointee.ty.is_sized(tcx.at(span), param_env) => {
PatKind::Constant { value: cv }
}
// FIXME: these can have very suprising behaviour where optimization levels or other
// compilation choices change the runtime behaviour of the match.
// See https://github.com/rust-lang/rust/issues/70861 for examples.
ty::FnPtr(..) | ty::RawPtr(..) => PatKind::Constant { value: cv },
ty::FnPtr(..) | ty::RawPtr(..) => {
if self.include_lint_checks && !self.saw_const_match_error.get() {
self.saw_const_match_error.set(true);
let msg = "function pointers and unsized pointers in patterns do not behave \
deterministically. \
See https://github.com/rust-lang/rust/issues/70861 for details.";
tcx.struct_span_lint_hir(
lint::builtin::POINTER_STRUCTURAL_MATCH,
id,
span,
|lint| lint.build(&msg).emit(),
);
}
PatKind::Constant { value: cv }
}
_ => {
tcx.sess.delay_span_bug(span, &format!("cannot make a pattern out of {}", cv.ty));
PatKind::Wild