go/types: fix error message for embedded non-interface types in interfaces

Fixes #10979.

Change-Id: Iac25645ba8181a56a75ddfcd29ff6d64c15c4f57
Reviewed-on: https://go-review.googlesource.com/10466
Reviewed-by: Alan Donovan <adonovan@google.com>

diff --git a/src/go/types/testdata/issues.src b/src/go/types/testdata/issues.src
index d08e0fd8786ea8c80ff1338aa67e7896fdd68973..595a6342b7b2cdcb595eb04f285c54a4c59fcd3f 100644 (file)
--- a/src/go/types/testdata/issues.src
+++ b/src/go/types/testdata/issues.src
@@ -71,3 +71,27 @@ func issue9473(a []int, b ...int) {
        append_(f0(), f1()... /* ERROR cannot use */ )
        append_(f0(), f2()... /* ERROR cannot use */ )
 }
+
+// Check that embedding a non-interface type in an interface results in a good error message.
+func issue10979() {
+       type _ interface {
+               int /* ERROR int is not an interface */
+       }
+       type T struct{}
+       type _ interface {
+               T /* ERROR T is not an interface */
+       }
+       type _ interface {
+               nosuchtype /* ERROR undeclared name: nosuchtype */
+       }
+       type _ interface {
+               fmt /* ERROR Nosuchtype not declared by package fmt */ .Nosuchtype
+       }
+       type _ interface {
+               nosuchpkg /* ERROR undeclared name: nosuchpkg */ .Nosuchtype
+       }
+       type I interface {
+               I /* ERROR I\.m \(value of type func\(I\)\) is not a type */ .m
+               m()
+       }
+}

diff --git a/src/go/types/typexpr.go b/src/go/types/typexpr.go
index f4e4dcb04018d71362743c4f4ec3ae6516745aee..3fc1574e805d9d237d676f773b157a887402dede 100644 (file)
--- a/src/go/types/typexpr.go
+++ b/src/go/types/typexpr.go
@@ -525,20 +525,14 @@ func (check *Checker) interfaceType(iface *Interface, ityp *ast.InterfaceType, d
        for _, e := range embedded {
                pos := e.Pos()
                typ := check.typExpr(e, nil, path)
+               // Determine underlying embedded (possibly incomplete) type
+               // by following its forward chain.
                named, _ := typ.(*Named)
-               if named == nil {
-                       if typ != Typ[Invalid] {
-                               check.invalidAST(pos, "%s is not named type", typ)
-                       }
-                       continue
-               }
-               // determine underlying (possibly incomplete) type
-               // by following its forward chain
-               u := underlying(named)
-               embed, _ := u.(*Interface)
+               under := underlying(named)
+               embed, _ := under.(*Interface)
                if embed == nil {
-                       if u != Typ[Invalid] {
-                               check.errorf(pos, "%s is not an interface", named)
+                       if typ != Typ[Invalid] {
+                               check.errorf(pos, "%s is not an interface", typ)
                        }
                        continue
                }