diff --git a/lib/token.cpp b/lib/token.cpp
index 1bb62dd8c5d..7b5e2464103 100644
--- a/lib/token.cpp
+++ b/lib/token.cpp
@@ -114,8 +114,15 @@ void Token::update_property_info()
     isStandardType(false);
 
     if (!mStr.empty()) {
-        if (mStr == "true" || mStr == "false")
-            tokType(eBoolean);
+        if (mStr == "true" || mStr == "false") {
+            if (mImpl->mVarId) {
+                if (mIsCpp)
+                    throw InternalError(this, "Internal error. VarId set for bool literal.");
+                tokType(eVariable);
+            }
+            else
+                tokType(eBoolean);
+        }
         else if (isStringLiteral(mStr)) {
             tokType(eString);
             isLong(isPrefixStringCharLiteral(mStr, '"', "L"));
diff --git a/lib/valueflow.cpp b/lib/valueflow.cpp
index 6079fc07c9e..dee1b35802d 100644
--- a/lib/valueflow.cpp
+++ b/lib/valueflow.cpp
@@ -562,7 +562,7 @@ static void valueFlowNumber(TokenList &tokenlist, const Settings& settings)
 
     if (tokenlist.isCPP() || settings.standards.c >= Standards::C23) {
         for (Token *tok = tokenlist.front(); tok; tok = tok->next()) {
-            if (tok->isName() && !tok->varId() && Token::Match(tok, "false|true")) {
+            if (tok->isName() && !tok->varId() && Token::Match(tok, "%bool%")) {
                 ValueFlow::Value value(tok->str() == "true");
                 if (!tok->isTemplateArg())
                     value.setKnown();
@@ -1208,7 +1208,7 @@ static void valueFlowImpossibleValues(TokenList& tokenList, const Settings& sett
     for (Token* tok = tokenList.front(); tok; tok = tok->next()) {
         if (tok->hasKnownIntValue())
             continue;
-        if (Token::Match(tok, "true|false"))
+        if (Token::Match(tok, "%bool%"))
             continue;
         if (astIsBool(tok) || Token::Match(tok, "%comp%")) {
             ValueFlow::Value lower{-1};
diff --git a/test/testvarid.cpp b/test/testvarid.cpp
index 8c83853b994..61f570c9f76 100644
--- a/test/testvarid.cpp
+++ b/test/testvarid.cpp
@@ -108,6 +108,7 @@ class TestVarID : public TestFixture {
         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(varid_cpp_keywords_in_c_code3);
+        TEST_CASE(varid_cpp_keywords_in_c_code4);
         TEST_CASE(varidFunctionCall1);
         TEST_CASE(varidFunctionCall2);
         TEST_CASE(varidFunctionCall3);
@@ -1468,6 +1469,17 @@ class TestVarID : public TestFixture {
         ASSERT_EQUALS(expected, tokenize(code, dinit(TokenizeOptions, $.cpp = false)));
     }
 
+    void varid_cpp_keywords_in_c_code4() { // #12120
+        {
+            const char code[] = "int false = 0;";
+            ASSERT_THROW_INTERNAL_EQUALS(tokenize(code, dinit(TokenizeOptions, $.cpp = true)), INTERNAL, "Internal error. VarId set for bool literal.");
+        }
+        {
+            const char code[] = "int false = 0;";
+            ASSERT_EQUALS("1: int false@1 ; false@1 = 0 ;\n", tokenize(code, dinit(TokenizeOptions, $.cpp = false)));
+        }
+    }
+
     void varidFunctionCall1() {
         const char code[] ="void f() {\n"
                             "    int x;\n"