From 0ebc24043bb267cf77ddd6c1d8b7d5ad9f82444d Mon Sep 17 00:00:00 2001
From: adamrk <ark.email@gmail.com>
Date: Thu, 25 Jun 2020 23:05:55 +0200
Subject: [PATCH] Infer type for slice wildcard patterns
---
crates/ra_hir_ty/src/infer/pat.rs | 9 +++++++--
crates/ra_hir_ty/src/tests/patterns.rs | 25 ++++++++++++++++++++++++
crates/ra_hir_ty/src/tests/regression.rs | 2 ++
3 files changed, 34 insertions(+), 2 deletions(-)
diff --git a/crates/ra_hir_ty/src/infer/pat.rs b/crates/ra_hir_ty/src/infer/pat.rs
index 23de2bd6b06..4dd4f9802d6 100644
--- a/crates/ra_hir_ty/src/infer/pat.rs
+++ b/crates/ra_hir_ty/src/infer/pat.rs
@@ -184,7 +184,7 @@ impl<'a> InferenceContext<'a> {
self.write_pat_ty(pat, bound_ty);
return inner_ty;
}
- Pat::Slice { prefix, slice: _slice, suffix } => {
+ Pat::Slice { prefix, slice, suffix } => {
let (container_ty, elem_ty) = match &expected {
ty_app!(TypeCtor::Array, st) => (TypeCtor::Array, st.as_single().clone()),
ty_app!(TypeCtor::Slice, st) => (TypeCtor::Slice, st.as_single().clone()),
@@ -195,7 +195,12 @@ impl<'a> InferenceContext<'a> {
self.infer_pat(*pat_id, &elem_ty, default_bm);
}
- Ty::apply_one(container_ty, elem_ty)
+ let pat_ty = Ty::apply_one(container_ty, elem_ty);
+ if let Some(slice_pat_id) = slice {
+ self.infer_pat(*slice_pat_id, &pat_ty, default_bm);
+ }
+
+ pat_ty
}
Pat::Wild => expected.clone(),
Pat::Range { start, end } => {
diff --git a/crates/ra_hir_ty/src/tests/patterns.rs b/crates/ra_hir_ty/src/tests/patterns.rs
index e5ef241caef..f937426bdba 100644
--- a/crates/ra_hir_ty/src/tests/patterns.rs
+++ b/crates/ra_hir_ty/src/tests/patterns.rs
@@ -627,3 +627,28 @@ fn test() {
"###
);
}
+
+#[test]
+fn slice_tail_pattern() {
+ assert_snapshot!(
+ infer(r#"
+fn foo(params: &[i32]) {
+ match params {
+ [head, tail @ ..] => {
+ }
+ }
+}
+"#),
+ @r###"
+ 7..13 'params': &[i32]
+ 23..92 '{ ... } }': ()
+ 29..90 'match ... }': ()
+ 35..41 'params': &[i32]
+ 52..69 '[head,... @ ..]': [i32]
+ 53..57 'head': &i32
+ 59..68 'tail @ ..': &[i32]
+ 66..68 '..': [i32]
+ 73..84 '{ }': ()
+ "###
+ );
+}
diff --git a/crates/ra_hir_ty/src/tests/regression.rs b/crates/ra_hir_ty/src/tests/regression.rs
index eedaa27bad6..aa37326dffd 100644
--- a/crates/ra_hir_ty/src/tests/regression.rs
+++ b/crates/ra_hir_ty/src/tests/regression.rs
@@ -500,6 +500,8 @@ fn foo(params: &[usize]) {
31..78 'match ... }': ()
37..43 'params': &[usize]
54..66 '[ps @ .., _]': [usize]
+ 55..62 'ps @ ..': &[usize]
+ 60..62 '..': [usize]
64..65 '_': usize
70..72 '{}': ()
"###