diff --git a/src/tools/moc/preprocessor.cpp b/src/tools/moc/preprocessor.cpp
index f0a61ce6217..11ea8d417e2 100644
--- a/src/tools/moc/preprocessor.cpp
+++ b/src/tools/moc/preprocessor.cpp
@@ -214,7 +214,9 @@ Symbols Preprocessor::tokenize(const QByteArray& input, int lineNum, Preprocesso
                     data -= 2;
                     break;
                 case DIGIT:
-                    while (isAsciiDigit(*data) || *data == '\'')
+                    {
+                    bool hasSeenTokenSeparator = false;;
+                    while (isAsciiDigit(*data) || (hasSeenTokenSeparator = *data == '\''))
                         ++data;
                     if (!*data || *data != '.') {
                         token = INTEGER_LITERAL;
@@ -223,15 +225,22 @@ Symbols Preprocessor::tokenize(const QByteArray& input, int lineNum, Preprocesso
                              || *data == 'b' || *data == 'B')
                             && *lexem == '0') {
                             ++data;
-                            while (isHexDigit(*data) || *data == '\'')
+                            while (isHexDigit(*data) || (hasSeenTokenSeparator = *data == '\''))
                                 ++data;
                         } else if (*data == 'L') // TODO: handle other suffixes
                             ++data;
+                        if (!hasSeenTokenSeparator) {
+                            while (is_ident_char(*data)) {
+                                ++data;
+                                token = IDENTIFIER;
+                            }
+                        }
                         break;
                     }
                     token = FLOATING_LITERAL;
                     ++data;
                     Q_FALLTHROUGH();
+                    }
                 case FLOATING_LITERAL:
                     while (isAsciiDigit(*data) || *data == '\'')
                         ++data;
diff --git a/tests/auto/tools/moc/tst_moc.cpp b/tests/auto/tools/moc/tst_moc.cpp
index a671d92dade..c947da3dd5b 100644
--- a/tests/auto/tools/moc/tst_moc.cpp
+++ b/tests/auto/tools/moc/tst_moc.cpp
@@ -84,6 +84,26 @@ namespace A {
 }
 #endif
 
+
+namespace TokenStartingWithNumber
+{
+Q_NAMESPACE
+
+#define FOR_EACH_ITEM( CALL ) \
+  CALL( EXAMPLE ) \
+  CALL( 123_EXAMPLE ) \
+  CALL( OTHER_EXAMPLE )
+
+enum FooItems
+{
+
+#define ENUM_ITEM(NAME, ...) FOO ## NAME,
+  FOR_EACH_ITEM( ENUM_ITEM )
+};
+
+Q_ENUM_NS(FooItems)
+}
+
 Q_DECLARE_METATYPE(const QMetaObject*);
 
 #define TESTEXPORTMACRO Q_DECL_EXPORT
@@ -851,6 +871,7 @@ private slots:
     void readWriteThroughBindable();
     void invokableCtors();
     void virtualInlineTaggedSlot();
+    void tokenStartingWithNumber();
 
 signals:
     void sigWithUnsignedArg(unsigned foo);
@@ -4667,6 +4688,15 @@ void tst_Moc::virtualInlineTaggedSlot()
     QCOMPARE(method.returnMetaType(), QMetaType::fromType<int>());
 }
 
+void tst_Moc::tokenStartingWithNumber()
+{
+    auto *mo  = &TokenStartingWithNumber::staticMetaObject;
+    int index = mo->indexOfEnumerator("FooItems");
+    QMetaEnum metaEnum = mo->enumerator(index);
+    QVERIFY(metaEnum.isValid());
+    QCOMPARE(metaEnum.keyCount(), 3);
+}
+
 QTEST_MAIN(tst_Moc)
 
 // the generated code must compile with QT_NO_KEYWORDS