charLiteralWithCharPtrCompare: Improved warning to catch any char literal

Author: danmar

lib/checkstring.cpp

@@ -168,7 +168,7 @@ void CheckString::checkSuspiciousStringCompare()
                 continue;
             if (varTok->tokType() == Token::eString || varTok->tokType() == Token::eNumber)
                 std::swap(varTok, litTok);
-            else if (litTok->tokType() != Token::eString && litTok->tokType() != Token::eNumber)
+            else if (!Token::Match(litTok, "%char%|%num%|%str%"))
                 continue;
 
             // Pointer addition?
@@ -200,10 +200,13 @@ void CheckString::checkSuspiciousStringCompare()
                 varTok = varTok->astParent();
             const std::string varname = varTok->expressionString();
 
+            const bool ischar(litTok->tokType() == Token::eChar ||
+                              (!litTok->originalName().empty() &&
+                               litTok->originalName().front() == '\''));
             if (litTok->tokType() == Token::eString) {
                 if (_tokenizer->isC() || (var && var->isArrayOrPointer()))
                     suspiciousStringCompareError(tok, varname);
-            } else if (litTok->originalName() == "'\\0'" && var && var->isPointer()) {
+            } else if (ischar && var && var->isPointer()) {
                 suspiciousStringCompareError_char(tok, varname);
             }
         }

test/teststring.cpp

@@ -367,7 +367,7 @@ class TestString : public TestFixture {
 
     void suspiciousStringCompare_char() {
         check("bool foo(char* c) {\n"
-              "    return c == '\\0';\n"
+              "    return c == 'x';\n"
               "}");
         ASSERT_EQUALS("[test.cpp:2]: (warning) Char literal compared with pointer 'c'. Did you intend to dereference it?\n", errout.str());