Fix #12249 Assert failure in ExpressionAnalyzer (#5731)

Author: chrchr-github

lib/symboldatabase.cpp

@@ -1732,7 +1732,7 @@ void SymbolDatabase::createSymbolDatabaseExprIds()
             } else if (tok->astParent() && !tok->astOperand1() && !tok->astOperand2()) {
                 if (tok->tokType() == Token::Type::eBracket)
                     continue;
-                if (tok->astParent()->isAssignmentOp())
+                if (tok->astParent()->str() == "=")
                     continue;
                 if (tok->isControlFlowKeyword())
                     continue;

test/cfg/std.cpp

@@ -603,7 +603,7 @@ void nullPointer_localtime_s(const std::time_t *restrict time, struct tm *restri
     (void)std::localtime_s(time, result);
 }
 
-void memleak_localtime_s(const std::time_t *restrict time, struct tm *restrict result)
+void memleak_localtime_s(const std::time_t *restrict time, struct tm *restrict result) // #9258
 {
     const time_t t = time(0);
     const struct tm* const now = new tm();

test/testvarid.cpp

@@ -242,6 +242,7 @@ class TestVarID : public TestFixture {
         TEST_CASE(exprid5);
         TEST_CASE(exprid6);
         TEST_CASE(exprid7);
+        TEST_CASE(exprid8);
 
         TEST_CASE(structuredBindings);
     }
@@ -3957,6 +3958,18 @@ class TestVarID : public TestFixture {
         ASSERT_EQUALS(expected, tokenizeExpr(code));
     }
 
+    void exprid8() {
+        const char code[] = "void f() {\n" // #12249
+                            "    std::string s;\n"
+                            "    (((s += \"--\") += std::string()) += \"=\");\n"
+                            "}\n";
+        const char expected[] = "1: void f ( ) {\n"
+                                "2: std ::@UNIQUE string s@1 ;\n"
+                                "3: ( ( s@1 +=@UNIQUE \"--\"@UNIQUE ) +=@UNIQUE std ::@UNIQUE string (@UNIQUE ) ) +=@UNIQUE \"=\"@UNIQUE ;\n"
+                                "4: }\n";
+        ASSERT_EQUALS(expected, tokenizeExpr(code));
+    }
+
     void structuredBindings() {
         const char code[] = "int foo() { auto [x,y] = xy(); return x+y; }";
         ASSERT_EQUALS("1: int foo ( ) { auto [ x@1 , y@2 ] = xy ( ) ; return x@1 + y@2 ; }\n",