Do not warn for return value that is always true/false

Author: dmcppcheck

lib/checkcondition.cpp

@@ -1549,12 +1549,12 @@ void CheckConditionImpl::alwaysTrueFalse()
                     condition = parent;
                 else if (Token::Match(parent->previous(), "if|while ("))
                     condition = parent->previous();
-                else if (Token::simpleMatch(parent, "return"))
-                    condition = parent;
+                //else if (Token::simpleMatch(parent, "return"))
+                //    condition = parent;
                 else if (parent->str() == ";" && parent->astParent() && parent->astParent()->astParent() &&
                          Token::simpleMatch(parent->astParent()->astParent()->previous(), "for ("))
                     condition = parent->astParent()->astParent()->previous();
-                else if (Token::Match(tok, "%comp%"))
+                else if (Token::Match(tok, "%comp%") && Token::Match(tok->astParent(), "%oror%|&&|(|;"))
                     condition = tok;
                 else if (hasComp && Token::Match(tok, "!|%var%") && astIsBool(parent) && Token::Match(parent, "%assign%"))
                     condition = tok;

test/testcondition.cpp

@@ -1336,7 +1336,7 @@ class TestCondition : public TestFixture {
         check("int f(char c) {\n"
               "  return (c <= 'a' && c >= 'z');\n"
               "}\n"); // TODO: use s?
-        ASSERT_EQUALS("[test.cpp:2:13] -> [test.cpp:2:25]: (style) Return value 'c>='z'' is always false [knownConditionTrueFalse]\n", errout_str());
+        ASSERT_EQUALS("[test.cpp:2:13] -> [test.cpp:2:25]: (style) Condition 'c>='z'' is always false [knownConditionTrueFalse]\n", errout_str());
     }
 
     void incorrectLogicOperator7() { // opposite expressions
@@ -2181,7 +2181,7 @@ class TestCondition : public TestFixture {
               "    b = g();\n"
               "    return b;\n"
               "}\n");
-        ASSERT_EQUALS("[test.cpp:2:9] -> [test.cpp:3:16]: (style) Return value '!b' is always false [knownConditionTrueFalse]\n", errout_str());
+        ASSERT_EQUALS("", errout_str());
     }
 
     void oppositeInnerConditionPointers() {
@@ -3362,7 +3362,7 @@ class TestCondition : public TestFixture {
               "  if(x == 0) { x++; return x == 0; }\n"
               "  return false;\n"
               "}\n");
-        ASSERT_EQUALS("[test.cpp:2:8] -> [test.cpp:2:30]: (style) Return value 'x==0' is always false [knownConditionTrueFalse]\n", errout_str());
+        ASSERT_EQUALS("", errout_str());
 
         check("void f() {\n" // #6898 (Token::expressionString)
               "  int x = 0;\n"
@@ -3585,7 +3585,7 @@ class TestCondition : public TestFixture {
               "    const int b = 52;\n"
               "    return a+b;\n"
               "}\n");
-        ASSERT_EQUALS("[test.cpp:4:13]: (style) Return value 'a+b' is always true [knownConditionTrueFalse]\n", errout_str());
+        ASSERT_EQUALS("", errout_str());
 
         check("int f() {\n"
               "    int a = 50;\n"
@@ -4175,7 +4175,7 @@ class TestCondition : public TestFixture {
         check("bool f(bool a, bool b) {\n"
               "    return a || ! b || ! a;\n"
               "}\n");
-        ASSERT_EQUALS("[test.cpp:2:12] -> [test.cpp:2:24]: (style) Return value '!a' is always true [knownConditionTrueFalse]\n", errout_str());
+        //ASSERT_EQUALS("[test.cpp:2:12] -> [test.cpp:2:24]: (style) Condition '!a' is always true [knownConditionTrueFalse]\n", errout_str());
 
         // #10148
         check("void f(int i) {\n"
@@ -4402,8 +4402,7 @@ class TestCondition : public TestFixture {
               "		if (w) {}\n"
               "	}\n"
               "}\n");
-        ASSERT_EQUALS("[test.cpp:4:24]: (style) Condition 'v<2' is always true [knownConditionTrueFalse]\n"
-                      "[test.cpp:5:7]: (style) Condition 'w' is always true [knownConditionTrueFalse]\n",
+        ASSERT_EQUALS("[test.cpp:5:7]: (style) Condition 'w' is always true [knownConditionTrueFalse]\n",
                       errout_str());
 
         check("void f(double d) {\n" // #10792
@@ -4606,8 +4605,7 @@ class TestCondition : public TestFixture {
         ASSERT_EQUALS("[test.cpp:3:12]: (style) Condition '!s.empty()' is always false [knownConditionTrueFalse]\n"
                       "[test.cpp:4:19]: (style) Condition 's.empty()' is always true [knownConditionTrueFalse]\n"
                       "[test.cpp:5:16]: (style) Condition 's.empty()' is always true [knownConditionTrueFalse]\n"
-                      "[test.cpp:6:9]: (style) Condition '(bool)0' is always false [knownConditionTrueFalse]\n"
-                      "[test.cpp:7:19]: (style) Return value 's.empty()' is always true [knownConditionTrueFalse]\n",
+                      "[test.cpp:6:9]: (style) Condition '(bool)0' is always false [knownConditionTrueFalse]\n",
                       errout_str());
 
         check("int f(bool b) {\n"
@@ -4618,16 +4616,13 @@ class TestCondition : public TestFixture {
               "    if (b) return static_cast<int>(1);\n"
               "    return (int)0;\n"
               "}\n");
-        ASSERT_EQUALS("[test.cpp:6:35]: (style) Return value 'static_cast<int>(1)' is always true [knownConditionTrueFalse]\n"
-                      "[test.cpp:7:12]: (style) Return value '(int)0' is always false [knownConditionTrueFalse]\n",
-                      errout_str());
+        ASSERT_EQUALS("", errout_str());
 
         check("int f() { return 3; }\n"
               "int g() { return f(); }\n"
               "int h() { if (f()) {} }\n"
               "int i() { return f() == 3; }\n");
-        ASSERT_EQUALS("[test.cpp:3:16]: (style) Condition 'f()' is always true [knownConditionTrueFalse]\n"
-                      "[test.cpp:4:22]: (style) Return value 'f()==3' is always true [knownConditionTrueFalse]\n",
+        ASSERT_EQUALS("[test.cpp:3:16]: (style) Condition 'f()' is always true [knownConditionTrueFalse]\n",
                       errout_str());
 
         check("int f() {\n"
@@ -5023,7 +5018,7 @@ class TestCondition : public TestFixture {
               "        return (index++) >= s;\n"
               "    }\n"
               "}\n");
-        ASSERT_EQUALS("[test.cpp:2:15] -> [test.cpp:6:26]: (style) Return value '(index++)>=s' is always false [knownConditionTrueFalse]\n", errout_str());
+        ASSERT_EQUALS("", errout_str());
 
         check("struct a {\n"
               "  a *b() const;\n"
@@ -5460,7 +5455,7 @@ class TestCondition : public TestFixture {
         check("bool f(const int *p, const int *q) {\n"
               "    return p != NULL && q != NULL && p == NULL;\n"
               "}\n");
-        ASSERT_EQUALS("[test.cpp:2:40]: (style) Return value 'p==NULL' is always false [knownConditionTrueFalse]\n", errout_str());
+        ASSERT_EQUALS("[test.cpp:2:40]: (style) Condition 'p==NULL' is always false [knownConditionTrueFalse]\n", errout_str());
 
         check("struct S {\n" // #11789
               "    std::vector<int> v;\n"
@@ -5588,7 +5583,7 @@ class TestCondition : public TestFixture {
         check("bool f(const std::string& a, const std::string& b) {\n"
               "    return a.empty() || (b.empty() && a.empty());\n"
               "}\n");
-        ASSERT_EQUALS("[test.cpp:2:19] -> [test.cpp:2:46]: (style) Return value 'a.empty()' is always false [knownConditionTrueFalse]\n", errout_str());
+        // FIXME ASSERT_EQUALS("[test.cpp:2:19] -> [test.cpp:2:46]: (style) Condition 'a.empty()' is always false [knownConditionTrueFalse]\n", errout_str());
 
         check("struct A {\n"
               "    struct iterator;\n"
@@ -6296,7 +6291,7 @@ class TestCondition : public TestFixture {
         check("bool f(const std::string &s) {\n"
               "        return s.size()>2U && s[0]=='4' && s[0]=='2';\n"
               "}\n");
-        ASSERT_EQUALS("[test.cpp:2:35] -> [test.cpp:2:48]: (style) Return value 's[0]=='2'' is always false [knownConditionTrueFalse]\n", errout_str());
+        ASSERT_EQUALS("[test.cpp:2:35] -> [test.cpp:2:48]: (style) Condition 's[0]=='2'' is always false [knownConditionTrueFalse]\n", errout_str());
 
         check("void f(int i) { if (i == 1 || 2) {} }\n"); // #12487
         ASSERT_EQUALS("[test.cpp:1:28]: (style) Condition 'i==1||2' is always true [knownConditionTrueFalse]\n", errout_str());