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authorLukas Wirth <[email protected]>2020-11-24 13:52:46 +0000
committerLukas Wirth <[email protected]>2020-11-24 15:11:40 +0000
commita5efefd3d788a6c5a7fb6a56a0da32f9bf62584e (patch)
tree727dfd24c866d9859c6fc497474f0637159aba1d /crates/hir_ty
parent35dd62e915905b6a93e2069a6d155cdf00cd254a (diff)
Properly infer tuple struct patterns when encountering ellipsis
Diffstat (limited to 'crates/hir_ty')
-rw-r--r--crates/hir_ty/src/infer/pat.rs31
-rw-r--r--crates/hir_ty/src/tests/patterns.rs48
2 files changed, 70 insertions, 9 deletions
diff --git a/crates/hir_ty/src/infer/pat.rs b/crates/hir_ty/src/infer/pat.rs
index b3fd74eab..b70ec55eb 100644
--- a/crates/hir_ty/src/infer/pat.rs
+++ b/crates/hir_ty/src/infer/pat.rs
@@ -23,6 +23,7 @@ impl<'a> InferenceContext<'a> {
23 expected: &Ty, 23 expected: &Ty,
24 default_bm: BindingMode, 24 default_bm: BindingMode,
25 id: PatId, 25 id: PatId,
26 ellipsis: Option<usize>,
26 ) -> Ty { 27 ) -> Ty {
27 let (ty, def) = self.resolve_variant(path); 28 let (ty, def) = self.resolve_variant(path);
28 let var_data = def.map(|it| variant_data(self.db.upcast(), it)); 29 let var_data = def.map(|it| variant_data(self.db.upcast(), it));
@@ -34,8 +35,15 @@ impl<'a> InferenceContext<'a> {
34 let substs = ty.substs().unwrap_or_else(Substs::empty); 35 let substs = ty.substs().unwrap_or_else(Substs::empty);
35 36
36 let field_tys = def.map(|it| self.db.field_types(it)).unwrap_or_default(); 37 let field_tys = def.map(|it| self.db.field_types(it)).unwrap_or_default();
38 let (pre, post) = match ellipsis {
39 Some(idx) => subpats.split_at(idx),
40 None => (&subpats[..], &[][..]),
41 };
42 let post_idx_offset = field_tys.iter().count() - post.len();
37 43
38 for (i, &subpat) in subpats.iter().enumerate() { 44 let pre_iter = pre.iter().enumerate();
45 let post_iter = (post_idx_offset..).zip(post.iter());
46 for (i, &subpat) in pre_iter.chain(post_iter) {
39 let expected_ty = var_data 47 let expected_ty = var_data
40 .as_ref() 48 .as_ref()
41 .and_then(|d| d.field(&Name::new_tuple_field(i))) 49 .and_then(|d| d.field(&Name::new_tuple_field(i)))
@@ -111,23 +119,23 @@ impl<'a> InferenceContext<'a> {
111 let expected = expected; 119 let expected = expected;
112 120
113 let ty = match &body[pat] { 121 let ty = match &body[pat] {
114 Pat::Tuple { ref args, ellipsis } => { 122 &Pat::Tuple { ref args, ellipsis } => {
115 let expectations = match expected.as_tuple() { 123 let expectations = match expected.as_tuple() {
116 Some(parameters) => &*parameters.0, 124 Some(parameters) => &*parameters.0,
117 _ => &[], 125 _ => &[],
118 }; 126 };
119 127
120 let (pre, post) = match ellipsis { 128 let (pre, post) = match ellipsis {
121 &Some(idx) => args.split_at(idx), 129 Some(idx) => args.split_at(idx),
122 None => (&args[..], &[][..]), 130 None => (&args[..], &[][..]),
123 }; 131 };
124 let uncovered_range = pre.len()..expectations.len().saturating_sub(post.len()); 132 let n_uncovered_patterns = expectations.len().saturating_sub(args.len());
125 let mut expectations_iter = expectations.iter().chain(repeat(&Ty::Unknown)); 133 let mut expectations_iter = expectations.iter().chain(repeat(&Ty::Unknown));
126 let mut infer_pat = |(&pat, ty)| self.infer_pat(pat, ty, default_bm); 134 let mut infer_pat = |(&pat, ty)| self.infer_pat(pat, ty, default_bm);
127 135
128 let mut inner_tys = Vec::with_capacity(expectations.len()); 136 let mut inner_tys = Vec::with_capacity(n_uncovered_patterns + args.len());
129 inner_tys.extend(pre.iter().zip(expectations_iter.by_ref()).map(&mut infer_pat)); 137 inner_tys.extend(pre.iter().zip(expectations_iter.by_ref()).map(&mut infer_pat));
130 inner_tys.extend(expectations_iter.by_ref().take(uncovered_range.len()).cloned()); 138 inner_tys.extend(expectations_iter.by_ref().take(n_uncovered_patterns).cloned());
131 inner_tys.extend(post.iter().zip(expectations_iter).map(infer_pat)); 139 inner_tys.extend(post.iter().zip(expectations_iter).map(infer_pat));
132 140
133 Ty::apply( 141 Ty::apply(
@@ -159,9 +167,14 @@ impl<'a> InferenceContext<'a> {
159 let subty = self.infer_pat(*pat, expectation, default_bm); 167 let subty = self.infer_pat(*pat, expectation, default_bm);
160 Ty::apply_one(TypeCtor::Ref(*mutability), subty) 168 Ty::apply_one(TypeCtor::Ref(*mutability), subty)
161 } 169 }
162 Pat::TupleStruct { path: p, args: subpats, .. } => { 170 Pat::TupleStruct { path: p, args: subpats, ellipsis } => self.infer_tuple_struct_pat(
163 self.infer_tuple_struct_pat(p.as_ref(), subpats, expected, default_bm, pat) 171 p.as_ref(),
164 } 172 subpats,
173 expected,
174 default_bm,
175 pat,
176 *ellipsis,
177 ),
165 Pat::Record { path: p, args: fields, ellipsis: _ } => { 178 Pat::Record { path: p, args: fields, ellipsis: _ } => {
166 self.infer_record_pat(p.as_ref(), fields, expected, default_bm, pat) 179 self.infer_record_pat(p.as_ref(), fields, expected, default_bm, pat)
167 } 180 }
diff --git a/crates/hir_ty/src/tests/patterns.rs b/crates/hir_ty/src/tests/patterns.rs
index 5776de280..5a5f48fd0 100644
--- a/crates/hir_ty/src/tests/patterns.rs
+++ b/crates/hir_ty/src/tests/patterns.rs
@@ -726,3 +726,51 @@ fn foo(tuple: (u8, i16, f32)) {
726 "#]], 726 "#]],
727 ); 727 );
728} 728}
729
730#[test]
731fn tuple_struct_ellipsis_pattern() {
732 check_infer(
733 r#"
734struct Tuple(u8, i16, f32);
735fn foo(tuple: Tuple) {
736 match tuple {
737 Tuple(.., b, c) => {},
738 Tuple(a, .., c) => {},
739 Tuple(a, b, ..) => {},
740 Tuple(a, b) => {/*too short*/}
741 Tuple(a, b, c, d) => {/*too long*/}
742 _ => {}
743 }
744}"#,
745 expect![[r#"
746 35..40 'tuple': Tuple
747 49..268 '{ ... } }': ()
748 55..266 'match ... }': ()
749 61..66 'tuple': Tuple
750 77..92 'Tuple(.., b, c)': Tuple
751 87..88 'b': i16
752 90..91 'c': f32
753 96..98 '{}': ()
754 108..123 'Tuple(a, .., c)': Tuple
755 114..115 'a': u8
756 121..122 'c': f32
757 127..129 '{}': ()
758 139..154 'Tuple(a, b, ..)': Tuple
759 145..146 'a': u8
760 148..149 'b': i16
761 158..160 '{}': ()
762 170..181 'Tuple(a, b)': Tuple
763 176..177 'a': u8
764 179..180 'b': i16
765 185..200 '{/*too short*/}': ()
766 209..226 'Tuple(... c, d)': Tuple
767 215..216 'a': u8
768 218..219 'b': i16
769 221..222 'c': f32
770 224..225 'd': {unknown}
771 230..244 '{/*too long*/}': ()
772 253..254 '_': Tuple
773 258..260 '{}': ()
774 "#]],
775 );
776}