From eda5272dfdc510b4d10bfcd359eae3103ae660e9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <daniel.marjamaki@gmail.com>
Date: Wed, 5 Aug 2015 11:15:54 +0200
Subject: [PATCH] Fixed #6875 (Improve 'Redundant condition' error message)

---
 lib/checkcondition.cpp | 28 +++++++++++++++++++++++++---
 test/testcondition.cpp | 12 ++++++------
 2 files changed, 31 insertions(+), 9 deletions(-)

diff --git a/lib/checkcondition.cpp b/lib/checkcondition.cpp
index ed2278ec3..debe04657 100644
--- a/lib/checkcondition.cpp
+++ b/lib/checkcondition.cpp
@@ -642,11 +642,33 @@ void CheckCondition::checkIncorrectLogicOperator()
             }
 
 
-            // 'A && (!A || B)' is equivalent with 'A || B'
-            if (printStyle && (tok->str() == "||") && tok->astOperand1() && tok->astOperand2() && tok->astOperand2()->str() == "&&") {
+            // 'A && (!A || B)' is equivalent with 'A && B'
+            // 'A || (!A && B)' is equivalent with 'A || B'
+            if (printStyle && tok->astOperand1() && tok->astOperand2() &&
+                ((tok->str() == "||" && tok->astOperand2()->str() == "&&") ||
+                 (tok->str() == "&&" && tok->astOperand2()->str() == "||"))) {
                 const Token* tok2 = tok->astOperand2()->astOperand1();
                 if (isOppositeCond(true, _tokenizer->isCPP(), tok->astOperand1(), tok2, _settings->library.functionpure)) {
-                    redundantConditionError(tok, tok2->expressionString() + ". 'A && (!A || B)' is equivalent to 'A || B'");
+                    std::string expr1(tok->astOperand1()->expressionString());
+                    std::string expr2(tok->astOperand2()->astOperand1()->expressionString());
+                    std::string expr3(tok->astOperand2()->astOperand2()->expressionString());
+
+                    if (expr1.length() + expr2.length() + expr3.length() > 50U) {
+                        if (expr1[0] == '!' && expr2[0] != '!') {
+                            expr1 = "!A";
+                            expr2 = "A";
+                        } else {
+                            expr1 = "!A";
+                            expr2 = "A";
+                        }
+
+                        expr3 = "B";
+                    }
+
+                    const std::string cond1 = expr1 + " " + tok->str() + " (" + expr2 + " " + tok->astOperand2()->str() + " " + expr3 + ")";
+                    const std::string cond2 = expr1 + " " + tok->str() + " " + expr3;
+
+                    redundantConditionError(tok, tok2->expressionString() + ". '" + cond1 + "' is equivalent to '" + cond2 + "'");
                     continue;
                 }
             }
diff --git a/test/testcondition.cpp b/test/testcondition.cpp
index ba1ab4be8..172fa95e2 100644
--- a/test/testcondition.cpp
+++ b/test/testcondition.cpp
@@ -1364,25 +1364,25 @@ private:
               "    int y = rand(), z = rand();\n"
               "    if (y || (!y && z));\n"
               "}");
-        ASSERT_EQUALS("[test.cpp:3]: (style) Redundant condition: !y. 'A && (!A || B)' is equivalent to 'A || B'\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:3]: (style) Redundant condition: !y. 'y || (!y && z)' is equivalent to 'y || z'\n", errout.str());
 
         check("void f() {\n"
               "    int y = rand(), z = rand();\n"
               "    if (y || !y && z);\n"
               "}");
-        ASSERT_EQUALS("[test.cpp:3]: (style) Redundant condition: !y. 'A && (!A || B)' is equivalent to 'A || B'\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:3]: (style) Redundant condition: !y. 'y || (!y && z)' is equivalent to 'y || z'\n", errout.str());
 
         check("void f() {\n"
               "    if (!a || a && b) {}\n"
               "}");
-        ASSERT_EQUALS("[test.cpp:2]: (style) Redundant condition: a. 'A && (!A || B)' is equivalent to 'A || B'\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:2]: (style) Redundant condition: a. '!a || (a && b)' is equivalent to '!a || b'\n", errout.str());
 
 
         check("void f() {\n"
               "    if (!tok->next()->function() || \n"
               "        (tok->next()->function() && tok->next()->function()->isConstructor()));\n"
               "}");
-        ASSERT_EQUALS("[test.cpp:2]: (style) Redundant condition: tok.next().function(). 'A && (!A || B)' is equivalent to 'A || B'\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:2]: (style) Redundant condition: tok.next().function(). '!A || (A && B)' is equivalent to '!A || B'\n", errout.str());
 
         check("void f() {\n"
               "    if (!tok->next()->function() || \n"
@@ -1400,7 +1400,7 @@ private:
               "    if (!tok->next(1)->function(1) || \n"
               "        (tok->next(1)->function(1) && tok->next(1)->function(1)->isConstructor()));\n"
               "}");
-        ASSERT_EQUALS("[test.cpp:2]: (style) Redundant condition: tok.next(1).function(1). 'A && (!A || B)' is equivalent to 'A || B'\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:2]: (style) Redundant condition: tok.next(1).function(1). '!A || (A && B)' is equivalent to '!A || B'\n", errout.str());
 
         check("void f() {\n"
               "    if (!tok->next()->function(1) || \n"
@@ -1412,7 +1412,7 @@ private:
               "   int y = rand(), z = rand();\n"
               "   if (y==0 || y!=0 && z);\n"
               "}");
-        ASSERT_EQUALS("[test.cpp:3]: (style) Redundant condition: y!=0. 'A && (!A || B)' is equivalent to 'A || B'\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:3]: (style) Redundant condition: y!=0. 'y==0 || (y!=0 && z)' is equivalent to 'y==0 || z'\n", errout.str());
 
         check("void f() {\n"
               "  if (x>0 || (x<0 && y)) {}\n"