Fix #12548 FN returnTempReference with braced initializer (regression) (#8409)

Co-authored-by: chrchr-github <noreply@github.com>

Author: chrchr-github

lib/astutils.cpp

@@ -461,7 +461,7 @@ bool isTemporary(const Token* tok, const Library* library, bool unknown)
             return false;
         return !branchTok->astOperand1()->valueType()->isTypeEqual(branchTok->astOperand2()->valueType());
     }
-    if (Token::simpleMatch(tok, "(") && tok->astOperand1() &&
+    if (Token::Match(tok, "(|{") && tok->astOperand1() &&
         (tok->astOperand2() || Token::simpleMatch(tok->next(), ")"))) {
         if (Token::simpleMatch(tok->astOperand1(), "typeid"))
             return false;
@@ -498,9 +498,6 @@ bool isTemporary(const Token* tok, const Library* library, bool unknown)
     // Currying a function is unknown in cppcheck
     if (Token::simpleMatch(tok, "(") && Token::simpleMatch(tok->astOperand1(), "("))
         return unknown;
-    if (Token::simpleMatch(tok, "{") && Token::simpleMatch(tok->astParent(), "return") && tok->astOperand1() &&
-        !tok->astOperand2())
-        return isTemporary(tok->astOperand1(), library);
     return true;
 }
 

test/testautovariables.cpp

@@ -131,6 +131,7 @@ class TestAutoVariables : public TestFixture {
         TEST_CASE(returnReference26);
         TEST_CASE(returnReference27);
         TEST_CASE(returnReference28);
+        TEST_CASE(returnReference29);
         TEST_CASE(returnReferenceFunction);
         TEST_CASE(returnReferenceContainer);
         TEST_CASE(returnReferenceLiteral);
@@ -1757,6 +1758,19 @@ class TestAutoVariables : public TestFixture {
         ASSERT_EQUALS("", errout_str());
     }
 
+    void returnReference29()
+    {
+        check("const std::string& f() {\n" // #12548
+              "    return std::string{};\n"
+              "}\n"
+              "const std::string& g() {\n"
+              "    return {};\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:2:23]: (error) Reference to temporary returned. [returnTempReference]\n"
+                      "[test.cpp:5:12]: (error) Reference to temporary returned. [returnTempReference]\n",
+                      errout_str());
+    }
+
     void returnReferenceFunction() {
         check("int& f(int& a) {\n"
               "    return a;\n"