Merge #683

683: fix AST for if expressions r=matklad a=matklad



Co-authored-by: Aleksey Kladov <aleksey.kladov@gmail.com>

crates/ra_hir/src/expr.rs

@@ -498,7 +498,13 @@ impl ExprCollector {
                     let then_branch = self.collect_block_opt(e.then_branch());
                     let else_branch = e
                         .else_branch()
-                        .map(|e| self.collect_block(e))
+                        .map(|b| match b {
+                            ast::ElseBranchFlavor::Block(it) => self.collect_block(it),
+                            ast::ElseBranchFlavor::IfExpr(elif) => {
+                                let expr: &ast::Expr = ast::Expr::cast(elif.syntax()).unwrap();
+                                self.collect_expr(expr)
+                            }
+                        })
                         .unwrap_or_else(|| self.empty_block());
                     let placeholder_pat = self.pats.alloc(Pat::Missing);
                     let arms = vec![
@@ -521,7 +527,13 @@ impl ExprCollector {
                 } else {
                     let condition = self.collect_expr_opt(e.condition().and_then(|c| c.expr()));
                     let then_branch = self.collect_block_opt(e.then_branch());
-                    let else_branch = e.else_branch().map(|e| self.collect_block(e));
+                    let else_branch = e.else_branch().map(|b| match b {
+                        ast::ElseBranchFlavor::Block(it) => self.collect_block(it),
+                        ast::ElseBranchFlavor::IfExpr(elif) => {
+                            let expr: &ast::Expr = ast::Expr::cast(elif.syntax()).unwrap();
+                            self.collect_expr(expr)
+                        }
+                    });
                     self.alloc_expr(
                         Expr::If {
                             condition,

crates/ra_hir/src/ty/snapshots/tests__infer_in_elseif.snap

@@ -0,0 +1,17 @@
+---
+created: "2019-01-26T21:36:52.714121185+00:00"
+creator: insta@0.5.2
+expression: "&result"
+source: crates/ra_hir/src/ty/tests.rs
+---
+[35; 38) 'foo': Foo
+[45; 109) '{     ...   } }': ()
+[51; 107) 'if tru...     }': ()
+[54; 58) 'true': bool
+[59; 67) '{      }': ()
+[73; 107) 'if fal...     }': i32
+[76; 81) 'false': bool
+[82; 107) '{     ...     }': i32
+[92; 95) 'foo': Foo
+[92; 101) 'foo.field': i32
+

crates/ra_hir/src/ty/tests.rs

@@ -284,6 +284,23 @@ fn test() {
     );
 }
 
+#[test]
+fn infer_in_elseif() {
+    check_inference(
+        "infer_in_elseif",
+        r#"
+struct Foo { field: i32 }
+fn main(foo: Foo) {
+    if true {
+
+    } else if false {
+        foo.field
+    }
+}
+"#,
+    )
+}
+
 #[test]
 fn infer_inherent_method() {
     check_inference(