Fix #12700 syntaxError with nested typedef (#6376)

Author: chrchr-github

lib/tokenize.cpp

@@ -8727,6 +8727,10 @@ void Tokenizer::findGarbageCode() const
             syntaxError(tok);
         if (tok->str() == "typedef") {
             for (const Token* tok2 = tok->next(); tok2 && tok2->str() != ";"; tok2 = tok2->next()) {
+                if (tok2->str() == "{") {
+                    tok2 = tok2->link();
+                    continue;
+                }
                 if (isUnevaluated(tok2)) {
                     tok2 = tok2->linkAt(1);
                     continue;

test/testsimplifytypedef.cpp

@@ -2516,7 +2516,7 @@ class TestSimplifyTypedef : public TestFixture {
 
     void simplifyTypedef106() { // ticket #3619 (segmentation fault)
         const char code[] = "typedef void f ();\ntypedef { f }";
-        ASSERT_THROW_INTERNAL(tok(code), SYNTAX);
+        ASSERT_THROW_INTERNAL_EQUALS(tok(code), INTERNAL, "Internal error. AST cyclic dependency.");
     }
 
     void simplifyTypedef107() { // ticket #3963 (bad code => segmentation fault)

test/testtokenize.cpp

@@ -7149,6 +7149,8 @@ class TestTokenizer : public TestFixture {
         ASSERT_NO_THROW(tokenizeAndStringify("template <typename T, int N>\n" // #12659
                                              "constexpr void f(T(&&a)[N]) {}"));
 
+        ASSERT_NO_THROW(tokenizeAndStringify("typedef struct { typedef int T; } S;")); // #12700
+
         ignore_errout();
     }