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typeck/pat.rs: extract check_pat_tuple.

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This commit is contained in:
Mazdak Farrokhzad 2019-08-24 04:30:03 +02:00
parent c16248d3a1
commit 3a51caa648
1 changed files with 58 additions and 45 deletions
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103
src/librustc_typeck/check/pat.rs
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@ -105,48 +105,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
expected_ty
}
PatKind::Tuple(ref elements, ddpos) => {
let mut expected_len = elements.len();
if ddpos.is_some() {
// Require known type only when `..` is present.
if let ty::Tuple(ref tys) =
self.structurally_resolved_type(pat.span, expected).sty {
expected_len = tys.len();
}
}
let max_len = cmp::max(expected_len, elements.len());
let element_tys_iter = (0..max_len).map(|_| {
Kind::from(self.next_ty_var(
// FIXME: `MiscVariable` for now -- obtaining the span and name information
// from all tuple elements isn't trivial.
TypeVariableOrigin {
kind: TypeVariableOriginKind::TypeInference,
span: pat.span,
},
))
});
let element_tys = tcx.mk_substs(element_tys_iter);
let pat_ty = tcx.mk_ty(ty::Tuple(element_tys));
if let Some(mut err) = self.demand_eqtype_diag(pat.span, expected, pat_ty) {
err.emit();
// Walk subpatterns with an expected type of `err` in this case to silence
// further errors being emitted when using the bindings. #50333
let element_tys_iter = (0..max_len).map(|_| tcx.types.err);
for (_, elem) in elements.iter().enumerate_and_adjust(max_len, ddpos) {
self.check_pat_walk(elem, &tcx.types.err, def_bm, discrim_span);
}
tcx.mk_tup(element_tys_iter)
} else {
for (i, elem) in elements.iter().enumerate_and_adjust(max_len, ddpos) {
self.check_pat_walk(
elem,
&element_tys[i].expect_ty(),
def_bm,
discrim_span,
);
}
pat_ty
}
self.check_pat_tuple(pat.span, elements, ddpos, expected, def_bm, discrim_span)
}
PatKind::Box(ref inner) => {
let inner_ty = self.next_ty_var(TypeVariableOrigin {
@ -807,7 +766,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
pat.hir_id);
if !pat_ty.is_fn() {
report_unexpected_res(res);
return self.tcx.types.err;
return tcx.types.err;
}
let variant = match res {
@ -833,8 +792,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
self.demand_eqtype_pat(pat.span, expected, pat_ty, match_arm_pat_span);
// Type-check subpatterns.
if subpats.len() == variant.fields.len() ||
subpats.len() < variant.fields.len() && ddpos.is_some() {
if subpats.len() == variant.fields.len()
|| subpats.len() < variant.fields.len() && ddpos.is_some()
{
let substs = match pat_ty.sty {
ty::Adt(_, substs) => substs,
_ => bug!("unexpected pattern type {:?}", pat_ty),
@ -861,6 +821,59 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
pat_ty
}
fn check_pat_tuple(
&self,
span: Span,
elements: &'tcx [P<hir::Pat>],
ddpos: Option<usize>,
expected: Ty<'tcx>,
def_bm: ty::BindingMode,
discrim_span: Option<Span>,
) -> Ty<'tcx> {
let tcx = self.tcx;
let mut expected_len = elements.len();
if ddpos.is_some() {
// Require known type only when `..` is present.
if let ty::Tuple(ref tys) = self.structurally_resolved_type(span, expected).sty {
expected_len = tys.len();
}
}
let max_len = cmp::max(expected_len, elements.len());
let element_tys_iter = (0..max_len).map(|_| {
Kind::from(self.next_ty_var(
// FIXME: `MiscVariable` for now -- obtaining the span and name information
// from all tuple elements isn't trivial.
TypeVariableOrigin {
kind: TypeVariableOriginKind::TypeInference,
span,
},
))
});
let element_tys = tcx.mk_substs(element_tys_iter);
let pat_ty = tcx.mk_ty(ty::Tuple(element_tys));
if let Some(mut err) = self.demand_eqtype_diag(span, expected, pat_ty) {
err.emit();
// Walk subpatterns with an expected type of `err` in this case to silence
// further errors being emitted when using the bindings. #50333
let element_tys_iter = (0..max_len).map(|_| tcx.types.err);
for (_, elem) in elements.iter().enumerate_and_adjust(max_len, ddpos) {
self.check_pat_walk(elem, &tcx.types.err, def_bm, discrim_span);
}
tcx.mk_tup(element_tys_iter)
} else {
for (i, elem) in elements.iter().enumerate_and_adjust(max_len, ddpos) {
self.check_pat_walk(
elem,
&element_tys[i].expect_ty(),
def_bm,
discrim_span,
);
}
pat_ty
}
}
fn check_struct_pat_fields(
&self,
adt_ty: Ty<'tcx>,