Add .get() to CheckedPtr when comparing with a std::string

When using a binary operand with CheckedPtr and std::string, you get an invalid operands to binary expression error.
With this CL, the rewriter matches CheckedPtr used with a std::string and adds .get() so the std::string/char* operator overrides gets used.

Bug: 1073933
Change-Id: I4854d4d272ba1d9a107e7e346bfbe363e6861c06
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2535908Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Łukasz Anforowicz <lukasza@chromium.org>
Commit-Queue: Keishi Hattori <keishi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#827861}

tools/clang/rewrite_raw_ptr_fields/RewriteRawPtrFields.cpp

@@ -1046,6 +1046,26 @@ int main(int argc, const char* argv[]) {
   match_finder.addMatcher(affected_ternary_operator_arg_matcher,
                           &affected_expr_rewriter);
 
+  // Affected string binary operator =========
+  // Given
+  //   struct S { const char* y; }
+  //   void foo(const S& s) {
+  //     std::string other;
+  //     bool v1 = s.y == other;
+  //     std::string v2 = s.y + other;
+  //   }
+  // binds the |s.y| expr if it matches the |affected_expr_matcher| above.
+  //
+  // See also testcases in tests/affected-expr-original.cc
+  auto std_string_expr_matcher =
+      expr(hasType(cxxRecordDecl(hasName("::std::basic_string"))));
+  auto affected_string_binary_operator_arg_matcher = cxxOperatorCallExpr(
+      hasAnyOverloadedOperatorName("+", "==", "!=", "<", "<=", ">", ">="),
+      hasAnyArgument(std_string_expr_matcher),
+      forEachArgumentWithParam(affected_expr_matcher, parmVarDecl()));
+  match_finder.addMatcher(affected_string_binary_operator_arg_matcher,
+                          &affected_expr_rewriter);
+
   // Calls to templated functions =========
   // Given
   //   struct S { int* y; };

tools/clang/rewrite_raw_ptr_fields/tests/affected-expr-expected.cc

@@ -174,6 +174,34 @@ void foo(int x) {
 
 }  // namespace ternary_operator_tests
 
+namespace string_comparison_operator_tests {
+
+void foo(int x) {
+  MyStruct my_struct;
+  std::string other_str = "other";
+
+  // To avoid the following error type:
+  //   error: invalid operands to binary expression ... basic_string ... and ...
+  //   CheckedPtr ...
+  // we need to append |.get()| to |my_struct.const_char_ptr| below.
+  //
+  // Expected rewrite: ... my_struct.const_char_ptr.get() ...
+  bool v1 = my_struct.const_char_ptr.get() == other_str;
+  bool v2 = other_str == my_struct.const_char_ptr.get();
+  bool v3 = my_struct.const_char_ptr.get() > other_str;
+  bool v4 = other_str > my_struct.const_char_ptr.get();
+  bool v5 = my_struct.const_char_ptr.get() >= other_str;
+  bool v6 = other_str >= my_struct.const_char_ptr.get();
+  bool v7 = my_struct.const_char_ptr.get() < other_str;
+  bool v8 = other_str < my_struct.const_char_ptr.get();
+  bool v9 = my_struct.const_char_ptr.get() <= other_str;
+  bool v10 = other_str <= my_struct.const_char_ptr.get();
+  std::string v11 = my_struct.const_char_ptr.get() + other_str;
+  std::string v12 = other_str + my_struct.const_char_ptr.get();
+}
+
+}  // namespace string_comparison_operator_tests
+
 namespace templated_functions {
 
 template <typename T>

tools/clang/rewrite_raw_ptr_fields/tests/affected-expr-original.cc

@@ -172,6 +172,34 @@ void foo(int x) {
 
 }  // namespace ternary_operator_tests
 
+namespace string_comparison_operator_tests {
+
+void foo(int x) {
+  MyStruct my_struct;
+  std::string other_str = "other";
+
+  // To avoid the following error type:
+  //   error: invalid operands to binary expression ... basic_string ... and ...
+  //   CheckedPtr ...
+  // we need to append |.get()| to |my_struct.const_char_ptr| below.
+  //
+  // Expected rewrite: ... my_struct.const_char_ptr.get() ...
+  bool v1 = my_struct.const_char_ptr == other_str;
+  bool v2 = other_str == my_struct.const_char_ptr;
+  bool v3 = my_struct.const_char_ptr > other_str;
+  bool v4 = other_str > my_struct.const_char_ptr;
+  bool v5 = my_struct.const_char_ptr >= other_str;
+  bool v6 = other_str >= my_struct.const_char_ptr;
+  bool v7 = my_struct.const_char_ptr < other_str;
+  bool v8 = other_str < my_struct.const_char_ptr;
+  bool v9 = my_struct.const_char_ptr <= other_str;
+  bool v10 = other_str <= my_struct.const_char_ptr;
+  std::string v11 = my_struct.const_char_ptr + other_str;
+  std::string v12 = other_str + my_struct.const_char_ptr;
+}
+
+}  // namespace string_comparison_operator_tests
+
 namespace templated_functions {
 
 template <typename T>