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typeck/pat.rs: extract diagnostics from check_pat_slice.

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This commit is contained in:
Mazdak Farrokhzad 2019-08-24 16:42:15 +02:00
parent 2ab69aef03
commit 729fbeb70b
1 changed files with 54 additions and 41 deletions
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95
src/librustc_typeck/check/pat.rs
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@ -1012,59 +1012,29 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
let expected_ty = self.structurally_resolved_type(span, expected);
let (inner_ty, slice_ty) = match expected_ty.sty {
ty::Array(inner_ty, size) => {
if let Some(size) = size.try_eval_usize(tcx, self.param_env) {
let slice_ty = if let Some(size) = size.try_eval_usize(tcx, self.param_env) {
let min_len = before.len() as u64 + after.len() as u64;
if slice.is_none() {
if min_len != size {
struct_span_err!(
tcx.sess, span, E0527,
"pattern requires {} elements but array has {}",
min_len, size
)
.span_label(span, format!("expected {} elements", size))
.emit();
self.error_scrutinee_inconsistent_length(span, min_len, size)
}
(inner_ty, tcx.types.err)
tcx.types.err
} else if let Some(rest) = size.checked_sub(min_len) {
(inner_ty, tcx.mk_array(inner_ty, rest))
tcx.mk_array(inner_ty, rest)
} else {
let msg = format!("pattern cannot match array of {} elements", size);
struct_span_err!(
tcx.sess, span, E0528,
"pattern requires at least {} elements but array has {}",
min_len, size
)
.span_label(span, msg)
.emit();
(inner_ty, tcx.types.err)
self.error_scrutinee_with_rest_inconsistent_length(span, min_len, size);
tcx.types.err
}
} else {
struct_span_err!(
tcx.sess, span, E0730,
"cannot pattern-match on an array without a fixed length",
)
.emit();
(inner_ty, tcx.types.err)
}
self.error_scrutinee_unfixed_length(span);
tcx.types.err
};
(inner_ty, slice_ty)
}
ty::Slice(inner_ty) => (inner_ty, expected_ty),
_ => {
if !expected_ty.references_error() {
let mut err = struct_span_err!(
tcx.sess, span, E0529,
"expected an array or slice, found `{}`",
expected_ty
);
if let ty::Ref(_, ty, _) = expected_ty.sty {
if let ty::Array(..) | ty::Slice(..) = ty.sty {
err.help("the semantics of slice patterns changed \
recently; see issue #62254");
}
}
let msg = format!("pattern cannot match with input type `{}`", expected_ty);
err.span_label(span, msg);
err.emit();
self.error_expected_array_or_slice(span, expected_ty);
}
(tcx.types.err, tcx.types.err)
}
@ -1081,4 +1051,47 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
}
expected_ty
}
fn error_scrutinee_inconsistent_length(&self, span: Span, min_len: u64, size: u64) {
struct_span_err!(
self.tcx.sess, span, E0527,
"pattern requires {} elements but array has {}",
min_len, size
)
.span_label(span, format!("expected {} elements", size))
.emit();
}
fn error_scrutinee_with_rest_inconsistent_length(&self, span: Span, min_len: u64, size: u64) {
struct_span_err!(
self.tcx.sess, span, E0528,
"pattern requires at least {} elements but array has {}",
min_len, size
)
.span_label(span, format!("pattern cannot match array of {} elements", size))
.emit();
}
fn error_scrutinee_unfixed_length(&self, span: Span) {
struct_span_err!(
self.tcx.sess, span, E0730,
"cannot pattern-match on an array without a fixed length",
)
.emit();
}
fn error_expected_array_or_slice(&self, span: Span, expected_ty: Ty<'tcx>) {
let mut err = struct_span_err!(
self.tcx.sess, span, E0529,
"expected an array or slice, found `{}`",
expected_ty
);
if let ty::Ref(_, ty, _) = expected_ty.sty {
if let ty::Array(..) | ty::Slice(..) = ty.sty {
err.help("the semantics of slice patterns changed recently; see issue #62254");
}
}
err.span_label(span, format!("pattern cannot match with input type `{}`", expected_ty));
err.emit();
}
}