diff --git a/src/go/types/decl.go b/src/go/types/decl.go
index 1e2790a171..a13442c951 100644
--- a/src/go/types/decl.go
+++ b/src/go/types/decl.go
@@ -333,8 +333,8 @@ func (check *Checker) constDecl(obj *Const, typ, init ast.Expr) {
 	assert(obj.typ == nil)
 
 	// use the correct value of iota
+	defer func(iota constant.Value) { check.iota = iota }(check.iota)
 	check.iota = obj.val
-	defer func() { check.iota = nil }()
 
 	// provide valid constant value under all circumstances
 	obj.val = constant.MakeUnknown()
diff --git a/src/go/types/testdata/const0.src b/src/go/types/testdata/const0.src
index 19fb1bdbbe..adbbf2863b 100644
--- a/src/go/types/testdata/const0.src
+++ b/src/go/types/testdata/const0.src
@@ -308,6 +308,8 @@ const (
 			_ = unsafe.Sizeof([iota-1]int{} == x) // assert types are equal
 			_ = unsafe.Sizeof([Two]int{} == x)    // assert types are equal
 		)
+		var z [iota]int                           // [2]int
+		_ = unsafe.Sizeof([2]int{} == z)          // assert types are equal
 	})
 	three = iota // the sequence continues
 )
@@ -334,3 +336,15 @@ var _ = []int64{
 	1 * 1e9,
 	5 * 1e9,
 }
+
+const _ = unsafe.Sizeof(func() {
+	const _ = 0
+	_ = iota
+
+	const (
+	   zero = iota
+	   one
+	)
+	assert(one == 1)
+	assert(iota == 0)
+})