bjoernager/rust
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make matching on NaN a hard error

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This commit is contained in:
Ralf Jung 2023-09-30 08:15:34 +02:00
parent 69db514ed9
commit cda3588572
9 changed files with 220 additions and 109 deletions
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9
compiler/rustc_mir_build/src/errors.rs
View file

@ -780,6 +780,15 @@ pub struct UnsizedPattern<'tcx> {
pub non_sm_ty: Ty<'tcx>,
}
#[derive(Diagnostic)]
#[diag(mir_build_nan_pattern)]
#[note]
#[help]
pub struct NaNPattern {
#[primary_span]
pub span: Span,
}
#[derive(LintDiagnostic)]
#[diag(mir_build_float_pattern)]
pub struct FloatPattern;

35
compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs
View file

@ -1,3 +1,4 @@
use rustc_apfloat::Float;
use rustc_hir as hir;
use rustc_hir::def_id::DefId;
use rustc_index::Idx;
@ -16,7 +17,7 @@ use std::cell::Cell;
use super::PatCtxt;
use crate::errors::{
FloatPattern, IndirectStructuralMatch, InvalidPattern, NonPartialEqMatch,
FloatPattern, IndirectStructuralMatch, InvalidPattern, NaNPattern, NonPartialEqMatch,
NontrivialStructuralMatch, PointerPattern, TypeNotStructural, UnionPattern, UnsizedPattern,
};
@ -317,16 +318,6 @@ impl<'tcx> ConstToPat<'tcx> {
let param_env = self.param_env;
let kind = match ty.kind() {
ty::Float(_) => {
self.saw_const_match_lint.set(true);
tcx.emit_node_span_lint(
lint::builtin::ILLEGAL_FLOATING_POINT_LITERAL_PATTERN,
id,
span,
FloatPattern,
);
return Err(FallbackToOpaqueConst);
}
// If the type is not structurally comparable, just emit the constant directly,
// causing the pattern match code to treat it opaquely.
// FIXME: This code doesn't emit errors itself, the caller emits the errors.
@ -486,6 +477,28 @@ impl<'tcx> ConstToPat<'tcx> {
}
}
},
ty::Float(flt) => {
let v = cv.unwrap_leaf();
let is_nan = match flt {
ty::FloatTy::F32 => v.try_to_f32().unwrap().is_nan(),
ty::FloatTy::F64 => v.try_to_f64().unwrap().is_nan(),
};
if is_nan {
// NaNs are not ever equal to anything so they make no sense as patterns.
// Also see <https://github.com/rust-lang/rfcs/pull/3535>.
let e = tcx.dcx().emit_err(NaNPattern { span });
self.saw_const_match_error.set(Some(e));
} else {
self.saw_const_match_lint.set(true);
tcx.emit_node_span_lint(
lint::builtin::ILLEGAL_FLOATING_POINT_LITERAL_PATTERN,
id,
span,
FloatPattern,
);
}
return Err(FallbackToOpaqueConst);
}
ty::Bool | ty::Char | ty::Int(_) | ty::Uint(_) | ty::RawPtr(..) => {
// The raw pointers we see here have been "vetted" by valtree construction to be
// just integers, so we simply allow them.