diff --git a/src/cmd/compile/internal/gc/typecheck.go b/src/cmd/compile/internal/gc/typecheck.go
index cc98c3ae69e6c2..bb78d8bf73d8d3 100644
--- a/src/cmd/compile/internal/gc/typecheck.go
+++ b/src/cmd/compile/internal/gc/typecheck.go
@@ -1263,7 +1263,7 @@ func typecheck1(n *Node, top int) *Node {
 			n.Op = OCALLFUNC
 			if t.Etype != TFUNC {
 				name := l.String()
-				if isBuiltinFuncName(name) {
+				if isBuiltinFuncName(name) && l.Name.Defn != nil {
 					// be more specific when the function
 					// name matches a predeclared function
 					yyerror("cannot call non-function %s (type %v), declared at %s",
diff --git a/test/fixedbugs/issue27356.go b/test/fixedbugs/issue27356.go
new file mode 100644
index 00000000000000..42784876a558a2
--- /dev/null
+++ b/test/fixedbugs/issue27356.go
@@ -0,0 +1,19 @@
+// errorcheck
+
+// Copyright 2018 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 27356: function parameter hiding built-in function results in compiler crash
+
+package p
+
+var a = []int{1,2,3}
+
+func _(len int) {
+	_ =  len(a) // ERROR "cannot call non-function"
+}
+
+var cap = false
+var _ = cap(a) // ERROR "cannot call non-function"
+