diff --git a/lib/tokenize.cpp b/lib/tokenize.cpp
index 911dd9902..1211505fe 100644
--- a/lib/tokenize.cpp
+++ b/lib/tokenize.cpp
@@ -79,6 +79,17 @@ static const Token * isFunctionHead(const Token *tok, const std::string &endsWit
     }
     return nullptr;
 }
+
+static bool isClassStructUnionStart(const Token * tok)
+{
+    if (tok->str() != "{")
+        return false;
+    const Token * tok2 = tok->previous();
+    while (tok2 && !Token::Match(tok2, "class|struct|union|{|;"))
+        tok2 = tok2->previous();
+    return Token::Match(tok2, "class|struct|union");
+}
+
 //---------------------------------------------------------------------------
 
 Tokenizer::Tokenizer() :
@@ -2590,14 +2601,14 @@ void Tokenizer::setVarId()
                 scopeInfo.push(variableId);
         } else if (tok->str() == "{") {
             // parse anonymous unions as part of the current scope
-            if (!(tok->strAt(-1) == "union" && Token::simpleMatch(tok->link(), "} ;")) &&
-                !(initlist && Token::Match(tok->previous(), "%name%|>|>>") && Token::Match(tok->link(), "} ,|{"))) {
+            if (!(initlist && Token::Match(tok->previous(), "%name%|>|>>") && Token::Match(tok->link(), "} ,|{"))) {
                 bool isExecutable;
                 if (tok->strAt(-1) == ")" || Token::Match(tok->tokAt(-2), ") %type%") ||
                     (initlist && tok->strAt(-1) == "}")) {
                     isExecutable = true;
                 } else {
-                    isExecutable = (initlist || tok->strAt(-1) == "else");
+                    isExecutable = ((scopeStack.top().isExecutable || initlist || tok->strAt(-1) == "else") &&
+                                    !isClassStructUnionStart(tok));
                     scopeInfo.push(variableId);
                 }
                 initlist = false;
diff --git a/test/testvarid.cpp b/test/testvarid.cpp
index e68a220a4..9a31ef0a1 100644
--- a/test/testvarid.cpp
+++ b/test/testvarid.cpp
@@ -85,6 +85,7 @@ private:
         TEST_CASE(varid54); // hang
         TEST_CASE(varid55); // #5868: Function::addArgument with varid 0 for argument named the same as a typedef
         TEST_CASE(varid56); // function with a throw()
+        TEST_CASE(varid57); // #6636: new scope by {}
         TEST_CASE(varid_cpp_keywords_in_c_code);
         TEST_CASE(varid_cpp_keywords_in_c_code2); // #5373: varid=0 for argument called "delete"
         TEST_CASE(varidFunctionCall1);
@@ -991,6 +992,37 @@ private:
         ASSERT_EQUALS(expected3, tokenize(code3, false, "test.cpp"));
     }
 
+    void varid57() { // #6636: new scope by {}
+        const char code1[] = "void SmoothPath() {\n"
+                             "    {\n" // new scope
+                             "        float dfx = (p2p0.x > 0.0f)?\n"
+                             "                    ((n0->xmax() * SQUARE_SIZE) - p0.x):\n"
+                             "                    ((n0->xmin() * SQUARE_SIZE) - p0.x);\n"
+                             "        float tx = dfx / dx;\n"
+                             "        if (hEdge) {\n"
+                             "        }\n"
+                             "        if (vEdge) {\n"
+                             "            pi.z = tx;\n"
+                             "        }\n"
+                             "    }\n"
+                             "}\n";
+        const char expected1[] = "\n\n##file 0\n"
+                                 "1: void SmoothPath ( ) {\n"
+                                 "2:\n"
+                                 "3: float dfx@1 ; dfx@1 = ( p2p0 . x > 0.0f ) ?\n"
+                                 "4: ( ( n0 . xmax ( ) * SQUARE_SIZE ) - p0 . x ) :\n"
+                                 "5: ( ( n0 . xmin ( ) * SQUARE_SIZE ) - p0 . x ) ;\n"
+                                 "6: float tx@2 ; tx@2 = dfx@1 / dx ;\n"
+                                 "7: if ( hEdge ) {\n"
+                                 "8: }\n"
+                                 "9: if ( vEdge ) {\n"
+                                 "10: pi . z = tx@2 ;\n"
+                                 "11: }\n"
+                                 "12:\n"
+                                 "13: }\n";
+        ASSERT_EQUALS(expected1, tokenize(code1, false, "test.cpp"));
+    }
+
     void varid_cpp_keywords_in_c_code() {
         const char code[] = "void f() {\n"
                             "    delete d;\n"