Fixed #6876 (valueFlowForward: lambda function)

lib/valueflow.cpp

@@ -1367,6 +1367,18 @@ static bool valueFlowForward(Token * const               startToken,
                     it->inconclusive = true;
             }
         }
+
+        // Lambda function
+        if (Token::simpleMatch(tok2, "= [") &&
+            Token::simpleMatch(tok2->linkAt(1), "] (") &&
+            Token::simpleMatch(tok2->linkAt(1)->linkAt(1), ") {")) {
+            const Token *bodyStart = tok2->linkAt(1)->linkAt(1)->next();
+            if (isVariableChanged(bodyStart, bodyStart->link(), varid)) {
+                if (settings->debugwarnings)
+                    bailout(tokenlist, errorLogger, tok2, "valueFlowForward, " + var->name() + " is changed in lambda function");
+                return false;
+            }
+        }
     }
     return true;
 }

test/testvalueflow.cpp

@@ -726,6 +726,17 @@ private:
                "}";
         ASSERT_EQUALS(false, testValueOfX(code, 4U, 0));
 
+        // lambda
+        code = "void f() {\n"
+               "    int x = 0;\n"
+               "    Q q = [&]() {\n"
+               "        if (x > 0) {}\n"
+               "        x++;\n"
+               "    };\n"
+               "    dosomething(q);\n"
+               "}\n";
+        ASSERT_EQUALS(false, testValueOfX(code, 4U, 0));
+
         // if/else
         code = "void f() {\n"
                "    int x = 123;\n"