Validate that all function-like-macro arguments are unique.

src/OpenGL/compiler/preprocessor/Diagnostics.cpp

@@ -78,6 +78,8 @@ std::string Diagnostics::message(ID id)
           return "Not enough arguments for macro";
       case MACRO_TOO_MANY_ARGS:
           return "Too many arguments for macro";
+      case MACRO_DUPLICATE_PARAMETER_NAMES:
+          return "duplicate macro parameter name";
       case CONDITIONAL_ENDIF_WITHOUT_IF:
           return "unexpected #endif found without a matching #if";
       case CONDITIONAL_ELSE_WITHOUT_IF:

src/OpenGL/compiler/preprocessor/Diagnostics.h

@@ -46,6 +46,7 @@ class Diagnostics
         MACRO_UNTERMINATED_INVOCATION,
         MACRO_TOO_FEW_ARGS,
         MACRO_TOO_MANY_ARGS,
+        MACRO_DUPLICATE_PARAMETER_NAMES,
         CONDITIONAL_ENDIF_WITHOUT_IF,
         CONDITIONAL_ELSE_WITHOUT_IF,
         CONDITIONAL_ELSE_AFTER_ELSE,

src/OpenGL/compiler/preprocessor/DirectiveParser.cpp

@@ -361,6 +361,14 @@ void DirectiveParser::parseDefine(Token* token)
             mTokenizer->lex(token);
             if (token->type != Token::IDENTIFIER)
                 break;
+
+            if (std::find(macro.parameters.begin(), macro.parameters.end(), token->text) != macro.parameters.end())
+            {
+                mDiagnostics->report(Diagnostics::MACRO_DUPLICATE_PARAMETER_NAMES,
+                                     token->location, token->text);
+                return;
+            }
+
             macro.parameters.push_back(token->text);
 
             mTokenizer->lex(token);  // Get ','.