Fix #13697 performance regression (hang) in 2.18dev (danmar#7372)

Author: chrchr-github

lib/symboldatabase.cpp

@@ -5000,7 +5000,7 @@ const Token *Scope::checkVariable(const Token *tok, AccessControl varaccess, con
 
         if (type == ScopeType::eFor && orig->strAt(-2) == "for") {
             for (const Token* tok2 = tok; tok2 && !Token::Match(tok2, "[;:]"); tok2 = tok2->next()) {
-                if (tok2->link()) {
+                if (tok2->link() && precedes(tok2, tok2->link())) {
                     tok2 = tok2->link();
                     continue;
                 }

test/testsymboldatabase.cpp

@@ -5982,18 +5982,32 @@ class TestSymbolDatabase : public TestFixture {
     }
 
     void createSymbolDatabaseFindAllScopes10() {
-        GET_SYMBOL_DB("void g() {\n"
-                      "    for (int i = 0, r = 1; i < r; ++i) {}\n"
-                      "}\n");
-        ASSERT(db);
-        ASSERT_EQUALS(3, db->scopeList.size());
-        ASSERT_EQUALS(2, db->scopeList.back().varlist.size());
-        const Token* const iTok = Token::findsimplematch(tokenizer.tokens(), "i");
-        const Token* const rTok = Token::findsimplematch(iTok, "r");
-        const Variable* i = iTok->variable(), *r = rTok->variable();
-        ASSERT(i != nullptr && r != nullptr);
-        ASSERT_EQUALS(i->typeStartToken(), r->typeStartToken());
-        ASSERT(i->valueType()->isTypeEqual(r->valueType()));
+        {
+            GET_SYMBOL_DB("void g() {\n"
+                          "    for (int i = 0, r = 1; i < r; ++i) {}\n"
+                          "}\n");
+            ASSERT(db);
+            ASSERT_EQUALS(3, db->scopeList.size());
+            ASSERT_EQUALS(2, db->scopeList.back().varlist.size());
+            const Token* const iTok = Token::findsimplematch(tokenizer.tokens(), "i");
+            const Token* const rTok = Token::findsimplematch(iTok, "r");
+            const Variable* i = iTok->variable(), * r = rTok->variable();
+            ASSERT(i != nullptr && r != nullptr);
+            ASSERT_EQUALS(i->typeStartToken(), r->typeStartToken());
+            ASSERT(i->valueType()->isTypeEqual(r->valueType()));
+        }
+        {
+            GET_SYMBOL_DB("void f() {\n" // #13697
+                          "    typedef void (*func_t)();\n"
+                          "    func_t a[] = { nullptr };\n"
+                          "    for (func_t* fp = a; *fp; fp++) {}\n"
+                          "}\n");
+            ASSERT(db); // don't hang
+            ASSERT_EQUALS(3, db->scopeList.size());
+            ASSERT_EQUALS(1, db->scopeList.back().varlist.size());
+            const Token* const fp = Token::findsimplematch(tokenizer.tokens(), "fp");
+            ASSERT(fp && fp->variable());
+        }
     }
 
     void createSymbolDatabaseIncompleteVars()