From e9b3cd548cd3e9f872344f518c01387dc6af814b Mon Sep 17 00:00:00 2001
From: Christian Kandeler <christian.kandeler@qt.io>
Date: Fri, 11 Aug 2023 17:48:47 +0200
Subject: [PATCH] CPlusPlus: Fix crash on weird-looking construct

This was misparsed as a function with an initializer (e.g. "= default"),
and then the empty id caused trouble later on.

Fixes: QTCREATORBUG-29386
Change-Id: I85a35db544e11ad85f50e3a15b1a071b36e79cd0
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: David Schulz <david.schulz@qt.io>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
---
 src/libs/3rdparty/cplusplus/Parser.cpp | 5 +++++
 tests/auto/cplusplus/ast/tst_ast.cpp   | 9 +++++++++
 2 files changed, 14 insertions(+)

diff --git a/src/libs/3rdparty/cplusplus/Parser.cpp b/src/libs/3rdparty/cplusplus/Parser.cpp
index 6bf19f59829..395556777dd 100644
--- a/src/libs/3rdparty/cplusplus/Parser.cpp
+++ b/src/libs/3rdparty/cplusplus/Parser.cpp
@@ -3020,6 +3020,11 @@ bool Parser::parseInitDeclarator(DeclaratorAST *&node, SpecifierListAST *decl_sp
         if (!_languageFeatures.cxx11Enabled || LA(2) == T_NUMERIC_LITERAL) {
             parseInitializer(node->initializer, &node->equal_token);
         } else {
+            if (LA(2) != T_NUMERIC_LITERAL && LA(2) != T_DEFAULT && LA(2) != T_DELETE) {
+                error(cursor(), "expected 'default', 'delete' or '0', got '%s'", tok(2).spell());
+                return false;
+            }
+
             node->equal_token = consumeToken();
 
             IdExpressionAST *id_expr = new (_pool) IdExpressionAST;
diff --git a/tests/auto/cplusplus/ast/tst_ast.cpp b/tests/auto/cplusplus/ast/tst_ast.cpp
index fc1ab3538e8..5790cb090ac 100644
--- a/tests/auto/cplusplus/ast/tst_ast.cpp
+++ b/tests/auto/cplusplus/ast/tst_ast.cpp
@@ -190,6 +190,7 @@ private slots:
     void enumDeclaration();
     void invalidEnumClassDeclaration();
     void invalidEnumWithDestructorId();
+    void invalidFunctionInitializer();
 };
 
 void tst_AST::gcc_attributes_1()
@@ -2052,6 +2053,14 @@ void tst_AST::invalidEnumWithDestructorId()
     QVERIFY(diag.errorCount != 0);
 }
 
+void tst_AST::invalidFunctionInitializer()
+{
+    QSharedPointer<TranslationUnit> unit(parse(
+        "int main() { a t=b; c d(e)=\"\"; }", TranslationUnit::ParseTranlationUnit, false, false, true));
+
+    QVERIFY(diag.errorCount != 0);
+}
+
 void tst_AST::initTestCase()
 {
     control.setDiagnosticClient(&diag);