Fix #14303 FN knownPointerToBool for function pointer / #13441 FN knownConditionTrueFalse (Compare function pointer with nullptr) (#8886)

Author: chrchr-github

lib/checkother.cpp

@@ -4446,7 +4446,7 @@ void CheckOtherImpl::checkKnownPointerToBool()
         for (const Token* tok = functionScope->bodyStart; tok != functionScope->bodyEnd; tok = tok->next()) {
             if (!tok->hasKnownIntValue())
                 continue;
-            if (!astIsPointer(tok))
+            if (!astIsPointer(tok) && !tok->function())
                 continue;
             if (Token::Match(tok->astParent(), "?|!|&&|%oror%|%comp%"))
                 continue;

lib/valueflow.cpp

@@ -1178,6 +1178,10 @@ static void valueFlowImpossibleValues(TokenList& tokenList, const Settings& sett
             ValueFlow::Value value{0};
             value.setImpossible();
             setTokenValue(tok, std::move(value), settings);
+        } else if (tok->function() && tok->scope()->isExecutable()) {
+            ValueFlow::Value value{0};
+            value.setImpossible();
+            setTokenValue(tok, std::move(value), settings);
         }
     }
 }
@@ -5162,7 +5166,8 @@ static void valueFlowInferCondition(TokenList& tokenlist, const Settings& settin
             }
         } else if (Token::Match(tok->astParent(), "?|&&|!|%oror%") ||
                    Token::Match(tok->astParent()->previous(), "if|while (") ||
-                   (astIsPointer(tok) && isUsedAsBool(tok, settings))) {
+                   (astIsPointer(tok) && isUsedAsBool(tok, settings)) ||
+                   tok->function()) {
             std::vector<ValueFlow::Value> result = infer(makeIntegralInferModel(), "!=", tok->values(), 0);
             if (result.size() != 1)
                 continue;

test/testcondition.cpp

@@ -5509,6 +5509,19 @@ class TestCondition : public TestFixture {
               "    std::size_t x;\n"
               "};\n");
         ASSERT_EQUALS("", errout_str());
+
+        check("int g();\n" // #13441
+              "void f() {\n"
+              "    int (*p)() = g;\n"
+              "    if (p == nullptr) {}\n"
+              "    if (g == nullptr) {}\n"
+              "    auto q = g;\n"
+              "    if (q == nullptr) {}\n"
+              "};\n");
+        ASSERT_EQUALS("[test.cpp:4:11]: (style) Condition 'p==nullptr' is always false [knownConditionTrueFalse]\n"
+                      "[test.cpp:5:11]: (style) Condition 'g==nullptr' is always false [knownConditionTrueFalse]\n"
+                      "[test.cpp:7:11]: (style) Condition 'q==nullptr' is always false [knownConditionTrueFalse]\n",
+                      errout_str());
     }
 
     void alwaysTrueContainer() {

test/testother.cpp

@@ -14072,6 +14072,12 @@ class TestOther : public TestFixture {
               "    g(b);\n"
               "}\n");
         ASSERT_EQUALS("", errout_str());
+
+        check("void g(bool);\n" // #14303
+              "void f() {\n"
+              "    g(g);\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:3:7]: (style) Pointer expression 'g' converted to bool is always true. [knownPointerToBool]\n", errout_str());
     }
 
     void iterateByValue() {