diff --git a/misc/cgo/testshared/src/exe/exe.go b/misc/cgo/testshared/src/exe/exe.go
index f01ad8ab78..433727112b 100644
--- a/misc/cgo/testshared/src/exe/exe.go
+++ b/misc/cgo/testshared/src/exe/exe.go
@@ -12,6 +12,13 @@ import (
 func DeclaredInMain() {
 }
 
+type C struct {
+}
+
+func F() *C {
+	return nil
+}
+
 func main() {
 	defer depBase.ImplementedInAsm()
 	// This code below causes various go.itab.* symbols to be generated in
@@ -20,4 +27,9 @@ func main() {
 	reflect.TypeOf(os.Stdout).Elem()
 	runtime.GC()
 	depBase.V = depBase.F() + 1
+
+	var c *C
+	if reflect.TypeOf(F).Out(0) != reflect.TypeOf(c) {
+		panic("bad reflection results, see golang.org/issue/18252")
+	}
 }
diff --git a/src/cmd/compile/internal/gc/reflect.go b/src/cmd/compile/internal/gc/reflect.go
index 4f9d92ed8a..61ac67c0bc 100644
--- a/src/cmd/compile/internal/gc/reflect.go
+++ b/src/cmd/compile/internal/gc/reflect.go
@@ -998,7 +998,6 @@ func itabname(t, itype *Type) *Node {
 		Fatalf("itabname(%v, %v)", t, itype)
 	}
 	s := Pkglookup(t.tconv(FmtLeft)+","+itype.tconv(FmtLeft), itabpkg)
-	Linksym(s).Set(obj.AttrLocal, true)
 	if s.Def == nil {
 		n := newname(s)
 		n.Type = Types[TUINT8]
@@ -1411,15 +1410,15 @@ func dumptypestructs() {
 		// }
 		o := dsymptr(i.sym, 0, dtypesym(i.itype), 0)
 		o = dsymptr(i.sym, o, dtypesym(i.t), 0)
-		o += Widthptr + 8                      // skip link/bad/unused fields
+		o += Widthptr + 8                      // skip link/bad/inhash fields
 		o += len(imethods(i.itype)) * Widthptr // skip fun method pointers
 		// at runtime the itab will contain pointers to types, other itabs and
 		// method functions. None are allocated on heap, so we can use obj.NOPTR.
-		ggloblsym(i.sym, int32(o), int16(obj.DUPOK|obj.NOPTR|obj.LOCAL))
+		ggloblsym(i.sym, int32(o), int16(obj.DUPOK|obj.NOPTR))
 
 		ilink := Pkglookup(i.t.tconv(FmtLeft)+","+i.itype.tconv(FmtLeft), itablinkpkg)
 		dsymptr(ilink, 0, i.sym, 0)
-		ggloblsym(ilink, int32(Widthptr), int16(obj.DUPOK|obj.RODATA|obj.LOCAL))
+		ggloblsym(ilink, int32(Widthptr), int16(obj.DUPOK|obj.RODATA))
 	}
 
 	// process ptabs
diff --git a/src/runtime/iface.go b/src/runtime/iface.go
index 18f5c588b4..46010d58fc 100644
--- a/src/runtime/iface.go
+++ b/src/runtime/iface.go
@@ -138,11 +138,8 @@ func additab(m *itab, locked, canfail bool) {
 		throw("invalid itab locking")
 	}
 	h := itabhash(inter, typ)
-	if m == hash[h] {
-		println("duplicate itab for", typ.string(), "and", inter.typ.string())
-		throw("duplicate itabs")
-	}
 	m.link = hash[h]
+	m.inhash = 1
 	atomicstorep(unsafe.Pointer(&hash[h]), unsafe.Pointer(m))
 }
 
@@ -150,7 +147,14 @@ func itabsinit() {
 	lock(&ifaceLock)
 	for _, md := range activeModules() {
 		for _, i := range md.itablinks {
-			additab(i, true, false)
+			// itablinks is a slice of pointers to the itabs used in this
+			// module. A given itab may be used in more than one module
+			// and thanks to the way global symbol resolution works, the
+			// pointed-to itab may already have been inserted into the
+			// global 'hash'.
+			if i.inhash == 0 {
+				additab(i, true, false)
+			}
 		}
 	}
 	unlock(&ifaceLock)
diff --git a/src/runtime/runtime2.go b/src/runtime/runtime2.go
index 72524f53af..acc9426142 100644
--- a/src/runtime/runtime2.go
+++ b/src/runtime/runtime2.go
@@ -640,7 +640,7 @@ type itab struct {
 	_type  *_type
 	link   *itab
 	bad    int32
-	unused int32
+	inhash int32      // has this itab been added to hash?
 	fun    [1]uintptr // variable sized
 }