fix a nasty off-by-one error.

llvm-svn: 51519

clang/lib/Rewrite/RewriteRope.cpp

@@ -578,7 +578,7 @@ void RopePieceBTreeInterior::erase(unsigned Offset, unsigned NumBytes) {
     NumBytes -= CurChild->size();
     CurChild->Destroy();
     --NumChildren;
-    if (i+1 != getNumChildren())
+    if (i != getNumChildren())
       memmove(&Children[i], &Children[i+1],
               (getNumChildren()-i)*sizeof(Children[0]));
   }

clang/test/Rewriter/crash.m

@@ -0,0 +1,14 @@
+// RUN: clang -rewrite-objc -o - %s
+// rdar://5950938
+@interface NSArray {}
++ (id)arrayWithObjects:(id)firstObj, ...;
+@end
+
+@interface NSConstantString {}
+@end
+
+int main() {
+    id foo = [NSArray arrayWithObjects:@"1", @"2", @"3", @"4", @"5", @"6", @"7", @"8", @"9", @"10", @"11", @"12", 0];
+    return 0;
+}
+