3 files changed, 36 insertions, 0 deletions

diff --git a/crates/ra_hir_ty/src/infer.rs b/crates/ra_hir_ty/src/infer.rs
index b6d9b3438..dfb6a435f 100644
--- a/crates/ra_hir_ty/src/infer.rs
+++ b/crates/ra_hir_ty/src/infer.rs
@@ -127,6 +127,7 @@ pub struct InferenceResult {
     field_resolutions: FxHashMap<ExprId, StructFieldId>,
     /// For each field in record literal, records the field it resolves to.
     record_field_resolutions: FxHashMap<ExprId, StructFieldId>,
+    record_field_pat_resolutions: FxHashMap<PatId, StructFieldId>,
     /// For each struct literal, records the variant it resolves to.
     variant_resolutions: FxHashMap<ExprOrPatId, VariantId>,
     /// For each associated item record what it resolves to
@@ -147,6 +148,9 @@ impl InferenceResult {
     pub fn record_field_resolution(&self, expr: ExprId) -> Option<StructFieldId> {
         self.record_field_resolutions.get(&expr).copied()
     }
+    pub fn record_field_pat_resolution(&self, pat: PatId) -> Option<StructFieldId> {
+        self.record_field_pat_resolutions.get(&pat).copied()
+    }
     pub fn variant_resolution_for_expr(&self, id: ExprId) -> Option<VariantId> {
         self.variant_resolutions.get(&id.into()).copied()
     }
diff --git a/crates/ra_hir_ty/src/infer/pat.rs b/crates/ra_hir_ty/src/infer/pat.rs
index 8ec4d4ace..7c2ad4384 100644
--- a/crates/ra_hir_ty/src/infer/pat.rs
+++ b/crates/ra_hir_ty/src/infer/pat.rs
@@ -7,6 +7,7 @@ use hir_def::{
     expr::{BindingAnnotation, Pat, PatId, RecordFieldPat},
     path::Path,
     type_ref::Mutability,
+    StructFieldId,
 };
 use hir_expand::name::Name;
 use test_utils::tested_by;
@@ -67,6 +68,11 @@ impl<'a> InferenceContext<'a> {
         let field_tys = def.map(|it| self.db.field_types(it)).unwrap_or_default();
         for subpat in subpats {
             let matching_field = var_data.as_ref().and_then(|it| it.field(&subpat.name));
+            if let Some(local_id) = matching_field {
+                let field_def = StructFieldId { parent: def.unwrap(), local_id };
+                self.result.record_field_pat_resolutions.insert(subpat.pat, field_def);
+            }
+
             let expected_ty =
                 matching_field.map_or(Ty::Unknown, |field| field_tys[field].clone().subst(&substs));
             let expected_ty = self.normalize_associated_types_in(expected_ty);
diff --git a/crates/ra_hir_ty/src/tests/patterns.rs b/crates/ra_hir_ty/src/tests/patterns.rs
index 07cbc521a..6ea51d5d3 100644
--- a/crates/ra_hir_ty/src/tests/patterns.rs
+++ b/crates/ra_hir_ty/src/tests/patterns.rs
@@ -455,3 +455,29 @@ fn test() {
     "###
     );
 }
+
+#[test]
+fn infer_guard() {
+    assert_snapshot!(
+        infer(r#"
+struct S;
+impl S { fn foo(&self) -> bool { false } }
+
+fn main() {
+    match S {
+        s if s.foo() => (),
+    }
+}
+    "#), @"
+        [28; 32) 'self': &S
+        [42; 51) '{ false }': bool
+        [44; 49) 'false': bool
+        [65; 116) '{     ...   } }': ()
+        [71; 114) 'match ...     }': ()
+        [77; 78) 'S': S
+        [89; 90) 's': S
+        [94; 95) 's': S
+        [94; 101) 's.foo()': bool
+        [105; 107) '()': ()
+    ")
+}