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lower_pattern_unadjusted: remove dead code.

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The code is dead because `check_pat_slice` will never have
`expected = ty::Ref(...)` due to default-binding-modes
(see `is_non_ref_pat`, `peel_off_references`).

Moreover, if the type is not `ty::Array(_) | ty::Slice(_)`
then `check_pat_slice` enters an error branch.
This commit is contained in:
Mazdak Farrokhzad 2019-12-19 19:23:43 +01:00
parent 7d99e4e4c2
commit 13b71018c1
2 changed files with 4 additions and 13 deletions
Download patch file Download diff file Expand all files Collapse all files

9
src/librustc_mir/hair/pattern/mod.rs
View file

@ -545,15 +545,6 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
hir::PatKind::Slice(ref prefix, ref slice, ref suffix) => {
match ty.kind {
ty::Ref(_, ty, _) =>
PatKind::Deref {
subpattern: Pat {
ty,
span: pat.span,
kind: Box::new(self.slice_or_array_pattern(
pat.span, ty, prefix, slice, suffix))
},
},
ty::Slice(..) |
ty::Array(..) =>
self.slice_or_array_pattern(pat.span, ty, prefix, slice, suffix),

8
src/librustc_typeck/check/pat.rs
View file

@ -1176,7 +1176,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
) -> Ty<'tcx> {
let tcx = self.tcx;
let expected = self.structurally_resolved_type(span, expected);
let (inner_ty, slice_ty) = match expected.kind {
let (inner_ty, slice_ty, expected) = match expected.kind {
// An array, so we might have something like `let [a, b, c] = [0, 1, 2];`.
ty::Array(inner_ty, size) => {
let slice_ty = if let Some(size) = size.try_eval_usize(tcx, self.param_env) {
@ -1206,15 +1206,15 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
self.error_scrutinee_unfixed_length(span);
tcx.types.err
};
(inner_ty, slice_ty)
(inner_ty, slice_ty, expected)
}
ty::Slice(inner_ty) => (inner_ty, expected),
ty::Slice(inner_ty) => (inner_ty, expected, expected),
// The expected type must be an array or slice, but was neither, so error.
_ => {
if !expected.references_error() {
self.error_expected_array_or_slice(span, expected);
}
(tcx.types.err, tcx.types.err)
(tcx.types.err, tcx.types.err, tcx.types.err)
}
};