Fix #12586 Crash in getReallocFuncInfo() with namespace alias (#6230)

Author: chrchr-github

lib/tokenize.cpp

@@ -10605,6 +10605,8 @@ void Tokenizer::simplifyNamespaceAliases()
                     }
 
                     if (tok2->strAt(1) == "::" && !alreadyHasNamespace(tokNameStart, tokNameEnd, tok2)) {
+                        if (Token::simpleMatch(tok2->tokAt(-1), "::") && tokNameStart->str() == "::")
+                            tok2->deletePrevious();
                         tok2->str(tokNameStart->str());
                         Token * tok3 = tokNameStart;
                         while (tok3 != tokNameEnd) {

test/testsimplifytokens.cpp

@@ -113,6 +113,7 @@ class TestSimplifyTokens : public TestFixture {
         TEST_CASE(simplifyNestedNamespace);
         TEST_CASE(simplifyNamespaceAliases1);
         TEST_CASE(simplifyNamespaceAliases2); // ticket #10281
+        TEST_CASE(simplifyNamespaceAliases3);
 
         TEST_CASE(simplifyKnownVariables2);
         TEST_CASE(simplifyKnownVariables3);
@@ -1502,6 +1503,18 @@ class TestSimplifyTokens : public TestFixture {
                           "}"));
     }
 
+    void simplifyNamespaceAliases3() {
+        ASSERT_EQUALS("namespace N { namespace O { int g ( ) ; } } " // #12586
+                      "void f ( ) { "
+                      "int s ; s = 3 * :: N :: O :: g ( ) ; "
+                      "}",
+                      tok("namespace N { namespace O { int g(); } }\n"
+                          "namespace _n = ::N::O;\n"
+                          "void f() {\n"
+                          "    int s = 3 * ::_n::g();\n"
+                          "}\n"));
+    }
+
 #define simplifyKnownVariables(code) simplifyKnownVariables_(code, __FILE__, __LINE__)
     std::string simplifyKnownVariables_(const char code[], const char* file, int line) {
         Tokenizer tokenizer(settings0, this);