Avoid C++ verifier template name collisions

src/idl_gen_cpp.cpp

@@ -682,16 +682,16 @@ class CppGenerator : public BaseGenerator {
         code_.SetValue("ID", "nullptr");
       }
 
-      code_ += "template <bool B = false>";
+      code_ += "template <bool VerifySizePrefixed = false>";
       code_ += "inline bool Verify{{STRUCT_NAME}}Buffer(";
-      code_ += "    ::flatbuffers::VerifierTemplate<B> &verifier) {";
+      code_ += "    ::flatbuffers::VerifierTemplate<VerifySizePrefixed> &verifier) {";
       code_ += "  return verifier.template VerifyBuffer<{{CPP_NAME}}>({{ID}});";
       code_ += "}";
       code_ += "";
 
-      code_ += "template <bool B = false>";
+      code_ += "template <bool VerifySizePrefixed = false>";
       code_ += "inline bool VerifySizePrefixed{{STRUCT_NAME}}Buffer(";
-      code_ += "    ::flatbuffers::VerifierTemplate<B> &verifier) {";
+      code_ += "    ::flatbuffers::VerifierTemplate<VerifySizePrefixed> &verifier) {";
       code_ +=
           "  return "
           "verifier.template "
@@ -1109,17 +1109,21 @@ class CppGenerator : public BaseGenerator {
 
   // For the initial declaration, we specify the template parameters,
   // including template default arguments.
-  std::string UnionVerifyTemplateDecl() { return "template <bool B = false>"; }
+  std::string UnionVerifyTemplateDecl() {
+    return "template <bool VerifySizePrefixed = false>";
+  }
 
   // For the subsequent definition, we must not redeclare the template default
   // arguments.
-  std::string UnionVerifyTemplateDef() { return "template <bool B>"; }
+  std::string UnionVerifyTemplateDef() {
+    return "template <bool VerifySizePrefixed>";
+  }
 
   // Should be used in conjunction with
   // UnionVerifyTemplateDecl()/UnionVerifyTemplateDef().
   std::string UnionVerifySignature(const EnumDef& enum_def) {
     return "bool Verify" + Name(enum_def) +
-           "(::flatbuffers::VerifierTemplate<B> &verifier, " +
+           "(::flatbuffers::VerifierTemplate<VerifySizePrefixed> &verifier, " +
            "const void *obj, " + Name(enum_def) + " type)";
   }
 
@@ -1131,7 +1135,7 @@ class CppGenerator : public BaseGenerator {
         opts_.scoped_enums ? name
                            : GenTypeBasic(enum_def.underlying_type, false);
     return "bool Verify" + name + "Vector" +
-           "(::flatbuffers::VerifierTemplate<B> &verifier, " +
+           "(::flatbuffers::VerifierTemplate<VerifySizePrefixed> &verifier, " +
            "const ::flatbuffers::Vector<::flatbuffers::Offset<void>> "
            "*values, " +
            "const ::flatbuffers::Vector<" + type + "> *types)";
@@ -3148,9 +3152,9 @@ class CppGenerator : public BaseGenerator {
 
     // Generate a verifier function that can check a buffer from an untrusted
     // source will never cause reads outside the buffer.
-    code_ += "  template <bool B = false>";
+    code_ += "  template <bool VerifySizePrefixed = false>";
     code_ +=
-        "  bool Verify(::flatbuffers::VerifierTemplate<B> "
+        "  bool Verify(::flatbuffers::VerifierTemplate<VerifySizePrefixed> "
         "&verifier) const {";
     code_ += "    return VerifyTableStart(verifier)\\";
     for (const auto& field : struct_def.fields.vec) {

tests/test_cpp_field_name_collision.py

@@ -0,0 +1,31 @@
+import subprocess
+import sys
+import tempfile
+from pathlib import Path
+
+
+SCHEMA = """namespace sample;
+table Record { B:int; }
+"""
+
+
+def main() -> int:
+  if len(sys.argv) != 2:
+    raise SystemExit("usage: test_cpp_field_name_collision.py FLATC")
+  flatc = Path(sys.argv[1]).resolve()
+  with tempfile.TemporaryDirectory() as directory:
+    root = Path(directory)
+    schema = root / "collision.fbs"
+    schema.write_text(SCHEMA, encoding="utf-8")
+    result = subprocess.run([str(flatc), "--cpp", "-o", str(root), str(schema)], capture_output=True, text=True)
+    if result.returncode != 0:
+      raise AssertionError(result.stderr or result.stdout)
+    generated = root / "collision_generated.h"
+    compile_result = subprocess.run(["c++", "-std=c++11", "-fsyntax-only", "-I", "include", str(generated)], capture_output=True, text=True)
+    if compile_result.returncode != 0:
+      raise AssertionError(compile_result.stderr or compile_result.stdout)
+  return 0
+
+
+if __name__ == "__main__":
+  raise SystemExit(main())