Type the return values of call expressions

crates/ra_hir/src/ty.rs

@@ -211,7 +211,6 @@ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 }
 
 pub fn type_for_fn(db: &impl HirDatabase, f: Function) -> Cancelable<Ty> {
-    eprintln!("type_for_fn {:?}", f.fn_id);
     let syntax = f.syntax(db);
     let node = syntax.borrowed();
     // TODO we ignore type parameters for now
@@ -397,7 +396,7 @@ fn infer_expr(&mut self, expr: ast::Expr) -> Cancelable<Ty> {
                 Ty::Unknown
             }
             ast::Expr::CallExpr(e) => {
-                let _callee_ty = if let Some(e) = e.expr() {
+                let callee_ty = if let Some(e) = e.expr() {
                     self.infer_expr(e)?
                 } else {
                     Ty::Unknown
@@ -408,7 +407,16 @@ fn infer_expr(&mut self, expr: ast::Expr) -> Cancelable<Ty> {
                         self.infer_expr(arg)?;
                     }
                 }
-                Ty::Unknown
+                match callee_ty {
+                    Ty::FnPtr(sig) => {
+                        sig.output.clone()
+                    }
+                    _ => {
+                        // not callable
+                        // TODO report an error?
+                        Ty::Unknown
+                    }
+                }
             }
             ast::Expr::MethodCallExpr(e) => {
                 let _receiver_ty = if let Some(e) = e.expr() {

crates/ra_hir/src/ty/tests/data/0003_paths.txt

@@ -2,8 +2,8 @@
 [14; 19) '{ 1 }': [unknown]
 [47; 52) '{ 1 }': [unknown]
 [49; 50) '1': [unknown]
-[81; 87) 'b::c()': [unknown]
+[81; 87) 'b::c()': u32
 [66; 90) '{     ...c(); }': ()
 [72; 73) 'a': fn() -> u32
-[72; 75) 'a()': [unknown]
+[72; 75) 'a()': u32
 [81; 85) 'b::c': fn() -> u32