From ac216880f5d1a3e5727b96d7b22433beec10382b Mon Sep 17 00:00:00 2001
From: Marcus Klaas de Vries <mail@marcusklaas.nl>
Date: Thu, 17 Jan 2019 00:08:10 +0100
Subject: Implement unlabeled struct field pattern inference

---
 crates/ra_hir/src/expr.rs     | 11 ++++++-----
 crates/ra_hir/src/ty.rs       | 15 ++++-----------
 crates/ra_hir/src/ty/tests.rs |  5 +++++
 3 files changed, 15 insertions(+), 16 deletions(-)

(limited to 'crates/ra_hir/src')

diff --git a/crates/ra_hir/src/expr.rs b/crates/ra_hir/src/expr.rs
index 893bad9cd..e7235c1a1 100644
--- a/crates/ra_hir/src/expr.rs
+++ b/crates/ra_hir/src/expr.rs
@@ -332,7 +332,7 @@ impl_arena_id!(PatId);
 #[derive(Debug, Clone, Eq, PartialEq)]
 pub struct FieldPat {
     pub(crate) name: Name,
-    pub(crate) pat: Option<PatId>,
+    pub(crate) pat: PatId,
 }
 
 /// Close relative to rustc's hir::PatKind
@@ -393,7 +393,7 @@ impl Pat {
                 total_iter.map(|pat| *pat).for_each(f);
             }
             Pat::Struct { args, .. } => {
-                args.iter().filter_map(|a| a.pat).for_each(f);
+                args.iter().map(|f| f.pat).for_each(f);
             }
         }
     }
@@ -821,9 +821,10 @@ impl ExprCollector {
                     .expect("every struct should have a field list")
                     .field_pats()
                     .into_iter()
-                    .map(|f| FieldPat {
-                        name: Name::new(f.ident),
-                        pat: f.pat.as_ref().map(|p| self.collect_pat(p)),
+                    .map(|f| {
+                        let name = Name::new(f.ident);
+                        let pat = self.collect_pat(&*f.pat);
+                        FieldPat { name, pat }
                     })
                     .collect();
 
diff --git a/crates/ra_hir/src/ty.rs b/crates/ra_hir/src/ty.rs
index 6bad61a2a..66940ec30 100644
--- a/crates/ra_hir/src/ty.rs
+++ b/crates/ra_hir/src/ty.rs
@@ -937,19 +937,12 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
         };
 
         for sub_pat in sub_pats {
-            let tyref = fields
-                .iter()
-                .find(|field| field.name == sub_pat.name)
-                .map(|field| &field.type_ref);
+            let matching_field = fields.iter().find(|field| field.name == sub_pat.name);
 
-            if let Some(typeref) = tyref {
+            if let Some(field) = matching_field {
+                let typeref = &field.type_ref;
                 let sub_ty = Ty::from_hir(self.db, &self.module, self.impl_block.as_ref(), typeref);
-
-                if let Some(pat) = sub_pat.pat {
-                    self.infer_pat(pat, &Expectation::has_type(sub_ty));
-                } else {
-                    // TODO: deal with this case: S { x, y }
-                }
+                self.infer_pat(sub_pat.pat, &Expectation::has_type(sub_ty));
             }
         }
 
diff --git a/crates/ra_hir/src/ty/tests.rs b/crates/ra_hir/src/ty/tests.rs
index 75fe2cc6e..10842f967 100644
--- a/crates/ra_hir/src/ty/tests.rs
+++ b/crates/ra_hir/src/ty/tests.rs
@@ -389,6 +389,11 @@ fn test() {
 
     let S(y, z) = foo;
     let E::A { x: new_var } = e;
+
+    match e {
+        E::A { x } => x,
+        E::B => 1,
+    };
 }
 "#,
         "adt_pattern.txt",
-- 
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