Keep decltype exception for standards where it is no keyword

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: autoantwort

lib/tokenize.cpp

@@ -9180,7 +9180,7 @@ void Tokenizer::findGarbageCode() const
                 // NAME(...)::  => NAME is most likely an unknown macro
                 // other cases are valid, e.g. (void)::f(), return (T)::x, new (p) ::T, decltype(x)::type
                 const Token* const prev = tok->linkAt(-1)->tokAt(-1);
-                if (Token::Match(prev, "%name% (") && !prev->isKeyword()) {
+                if (Token::Match(prev, "%name% (") && !prev->isKeyword() && prev->str() != "decltype") { // decltype is no keyword before C++11
                     if (prev->isUpperCaseName())
                         unknownMacroError(prev);
                     else

test/testtokenize.cpp

@@ -8135,7 +8135,7 @@ class TestTokenizer : public TestFixture {
                                              "    *p = -*p;\n"
                                              "}\n"));
 
-        ASSERT_NO_THROW(tokenizeAndStringify("void f(void* h) {\n" // cast before global scope operator
+        ASSERT_NO_THROW(tokenizeAndStringify("void f(void* h) {\n" // #15079
                                              "    (void)::CloseHandle(h);\n"
                                              "    int i = (int)::GetTickCount();\n"
                                              "    g((unsigned char)::toupper(i));\n"
@@ -8150,6 +8150,12 @@ class TestTokenizer : public TestFixture {
         ASSERT_NO_THROW(tokenizeAndStringify("struct S { using type = int; };\n"
                                              "S s;\n"
                                              "decltype(s)::type i;\n"));
+        {
+            const Settings s = settingsBuilder().cpp(Standards::CPP03).build();
+            ASSERT_NO_THROW(tokenizeAndStringify("struct S { typedef int type; };\n"
+                                                 "S s;\n"
+                                                 "decltype(s)::type i;\n", s));
+        }
 
         ignore_errout();