diff --git a/src/cmd/compile/internal/types2/call.go b/src/cmd/compile/internal/types2/call.go
index fe3c17fc6b..5ecd54ab0b 100644
--- a/src/cmd/compile/internal/types2/call.go
+++ b/src/cmd/compile/internal/types2/call.go
@@ -128,6 +128,10 @@ func (check *Checker) call(x *operand, call *syntax.CallExpr) exprKind {
 						break
 					}
 				}
+				if call.HasDots {
+					check.errorf(call.ArgList[0], "invalid use of ... in type conversion to %s)", T)
+					break
+				}
 				check.conversion(x, T)
 			}
 		default:
diff --git a/src/cmd/compile/internal/types2/fixedbugs/issue43124.src b/src/cmd/compile/internal/types2/fixedbugs/issue43124.src
new file mode 100644
index 0000000000..7e48c2211b
--- /dev/null
+++ b/src/cmd/compile/internal/types2/fixedbugs/issue43124.src
@@ -0,0 +1,16 @@
+// Copyright 2020 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.
+
+package p
+
+var _ = int(0 /* ERROR invalid use of \.\.\. in type conversion */ ...)
+
+// test case from issue
+
+type M []string
+
+var (
+	x = []string{"a", "b"}
+	_ = M(x /* ERROR invalid use of \.\.\. in type conversion */ ...)
+)