Add test cases for #7899, #7974, #9256 (#3726)

* Add test case for #7899 and #7974

* Add test case for ##9256

test/testcondition.cpp

@@ -3858,6 +3858,14 @@ private:
               "  return foo < bar;\n"
               "}\n");
         ASSERT_EQUALS("", errout.str());
+
+        // #9256
+        check("bool f() {\n"
+              "    bool b = false;\n"
+              "    b = true;\n"
+              "    return b;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
     }
 
     void alwaysTrueSymbolic()

test/testother.cpp

@@ -147,6 +147,7 @@ private:
         TEST_CASE(duplicateExpression10); // #9485
         TEST_CASE(duplicateExpression11); // #8916 (function call)
         TEST_CASE(duplicateExpression12); // #10026
+        TEST_CASE(duplicateExpression13); // #7899
         TEST_CASE(duplicateExpressionLoop);
         TEST_CASE(duplicateValueTernary);
         TEST_CASE(duplicateExpressionTernary); // #6391
@@ -5451,6 +5452,13 @@ private:
         ASSERT_EQUALS("[test.cpp:3] -> [test.cpp:4]: (style) Same expression on both sides of '-'.\n", errout.str());
     }
 
+    void duplicateExpression13() { //#7899
+        check("void f() {\n"
+              "    if (sizeof(long) == sizeof(long long)) {}\n"
+              "}");
+        ASSERT_EQUALS("", errout.str());
+    }
+
     void duplicateExpressionLoop() {
         check("void f() {\n"
               "    int a = 1;\n"

test/testunusedfunctions.cpp

@@ -53,6 +53,7 @@ private:
         TEST_CASE(unusedMain);
         TEST_CASE(initializationIsNotAFunction);
         TEST_CASE(operator1);   // #3195
+        TEST_CASE(operator2);   // #7974
         TEST_CASE(returnRef);
         TEST_CASE(attribute); // #3471 - FP __attribute__(constructor)
         TEST_CASE(initializer_list);
@@ -327,6 +328,19 @@ private:
         ASSERT_EQUALS("", errout.str());
     }
 
+    void operator2() { // #7974
+        check("bool operator==(const data_t& a, const data_t& b) {\n"
+              "    return (a.fd == b.fd);\n"
+              "}\n"
+              "bool operator==(const event& a, const event& b) {\n"
+              "    return ((a.events == b.events) && (a.data == b.data));\n"
+              "}\n"
+              "int main(event a, event b) {\n"
+              "    return a == b;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+    }
+
     void returnRef() {
         check("int& foo() {return x;}");
         ASSERT_EQUALS("[test.cpp:1]: (style) The function 'foo' is never used.\n", errout.str());