1 files changed, 13 insertions, 0 deletions
diff --git a/src/strings/strings.go b/src/strings/strings.go
index c5355db9a2..10922f3c1d 100644
--- a/src/strings/strings.go
+++ b/src/strings/strings.go
@@ -418,7 +418,20 @@ func Map(mapping func(rune) rune, s string) string {
 }
 
 // Repeat returns a new string consisting of count copies of the string s.
+//
+// It panics if count is negative or if
+// the result of (len(s) * count) overflows.
 func Repeat(s string, count int) string {
+	// Since we cannot return an error on overflow,
+	// we should panic if the repeat will generate
+	// an overflow.
+	// See Issue golang.org/issue/16237
+	if count < 0 {
+		panic("strings: negative Repeat count")
+	} else if count > 0 && len(s)*count/count != len(s) {
+		panic("strings: Repeat count causes overflow")
+	}
+
 	b := make([]byte, len(s)*count)
 	bp := copy(b, s)
 	for bp < len(b) {