diff --git a/src/cmd/compile/internal/gc/const.go b/src/cmd/compile/internal/gc/const.go
index de7df645e6..0e6d838eaa 100644
--- a/src/cmd/compile/internal/gc/const.go
+++ b/src/cmd/compile/internal/gc/const.go
@@ -1280,8 +1280,6 @@ func indexconst(n *Node) int64 {
 //
 // Expressions derived from nil, like string([]byte(nil)), while they
 // may be known at compile time, are not Go language constants.
-// Only called for expressions known to evaluate to compile-time
-// constants.
 func (n *Node) isGoConst() bool {
 	if n.Orig != nil {
 		n = n.Orig
@@ -1359,17 +1357,6 @@ func (n *Node) isGoConst() bool {
 			return true
 		}
 
-	case ONAME:
-		l := asNode(n.Sym.Def)
-		if l != nil && l.Op == OLITERAL && n.Val().Ctype() != CTNIL {
-			return true
-		}
-
-	case ONONAME:
-		if asNode(n.Sym.Def) != nil && asNode(n.Sym.Def).Op == OIOTA {
-			return true
-		}
-
 	case OALIGNOF, OOFFSETOF, OSIZEOF:
 		return true
 	}
diff --git a/test/fixedbugs/issue30430.go b/test/fixedbugs/issue30430.go
new file mode 100644
index 0000000000..6c27b82881
--- /dev/null
+++ b/test/fixedbugs/issue30430.go
@@ -0,0 +1,17 @@
+// compile
+
+// Copyright 2019 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.
+
+// Issue 30430: isGoConst returned true for non-const variables,
+// resulting in ICE.
+
+package p
+
+func f() {
+	var s string
+	_ = map[string]string{s: ""}
+}
+
+const s = ""