code review 7437049: go/types: "missing return" check

src/pkg/go/types/check.go

 // Copyright 2011 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 // This file implements the Check function, which typechecks a package.
 
 package types
 
 import (
         "fmt"
@@ skipping 463 matching lines @@
                 f := check.funclist[i]
                 if trace {
                         s := "<function literal>"
                         if f.obj != nil {
                                 s = f.obj.Name
                         }
                         fmt.Println("---", s)
                 }
                 check.funcsig = f.sig
                 check.stmtList(f.body.List)
+                if len(f.sig.Results) > 0 && f.body != nil && !check.isTerminating(f.body, "") {
+                        check.errorf(f.body.Rbrace, "missing return")
+                }
         }
 
         // remaining untyped expressions must indeed be untyped
         if debug {
                 for x, typ := range check.untyped {
                         if !isUntyped(typ) {
                                 check.dump("%s: %s (type %s) is not untyped", x.Pos(), x, typ)
                                 panic(0)
                         }
                 }
         }
 
         // notify client of any untyped types left
         // TODO(gri) Consider doing this before and
         // after function body checking for smaller
         // map size and more immediate feedback.
         if ctxt.Expr != nil {
                 for x, typ := range check.untyped {
                         ctxt.Expr(x, typ, check.constants[x])
                 }
         }
 
         return
 }