Implement LWG 2946, 3075 and 3076. Reviewed as https://reviews.llvm.org/D48616

llvm-svn: 336132

libcxx/test/std/strings/basic.string/string.modifiers/string_replace/iter_iter_string.pass.cpp

@@ -281,4 +281,13 @@ int main()
     test2<S>();
     }
 #endif
+
+#if TEST_STD_VER > 3
+    {   // LWG 2946
+    std::string s = "  ";
+    s.replace(s.cbegin(), s.cend(), {"abc", 1});
+    assert(s.size() == 1);
+    assert(s == "a");
+    }
+#endif
 }

libcxx/test/std/strings/basic.string/string.modifiers/string_replace/size_size_string.pass.cpp

@@ -379,4 +379,13 @@ int main()
     test2<S>();
     }
 #endif
+
+#if TEST_STD_VER > 3
+    {   // LWG 2946
+    std::string s = " ";
+    s.replace(0, 1, {"abc", 1});
+    assert(s.size() == 1);
+    assert(s == "a");
+    }
+#endif
 }