From 82eec11898197a380e1a643eba78e6ca68b27bab Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <daniel.marjamaki@gmail.com>
Date: Sun, 25 Aug 2019 09:45:39 +0200
Subject: [PATCH] Created redundantInitialization id

---
 lib/checkother.cpp | 13 +++++++++++++
 lib/checkother.h   |  4 +++-
 test/testother.cpp | 27 +++++++++++++++++++++++++++
 3 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/lib/checkother.cpp b/lib/checkother.cpp
index 8b60d446d..a4d079784 100644
--- a/lib/checkother.cpp
+++ b/lib/checkother.cpp
@@ -433,7 +433,9 @@ void CheckOther::checkRedundantAssignment()
 
                 // Do not warn about redundant initialization when rhs is trivial
                 // TODO : do not simplify the variable declarations
+                bool isInitialization = false;
                 if (Token::Match(tok->tokAt(-3), "%var% ; %var% =") && tok->previous()->variable() && tok->previous()->variable()->nameToken() == tok->tokAt(-3) && tok->tokAt(-3)->linenr() == tok->previous()->linenr()) {
+                    isInitialization = true;
                     bool trivial = true;
                     visitAstNodes(tok->astOperand2(),
                     [&](const Token *rhs) {
@@ -507,6 +509,8 @@ void CheckOther::checkRedundantAssignment()
                 // warn
                 if (hasCase)
                     redundantAssignmentInSwitchError(tok, nextAssign, tok->astOperand1()->expressionString());
+                else if (isInitialization)
+                    redundantInitializationError(tok, nextAssign, tok->astOperand1()->expressionString(), inconclusive);
                 else
                     redundantAssignmentError(tok, nextAssign, tok->astOperand1()->expressionString(), inconclusive);
             }
@@ -544,6 +548,15 @@ void CheckOther::redundantAssignmentError(const Token *tok1, const Token* tok2,
                     "Variable '$symbol' is reassigned a value before the old one has been used.", CWE563, false);
 }
 
+void CheckOther::redundantInitializationError(const Token *tok1, const Token* tok2, const std::string& var, bool inconclusive)
+{
+    const std::list<const Token *> callstack = { tok1, tok2 };
+    reportError(callstack, Severity::style, "redundantInitialization",
+                "$symbol:" + var + "\nRedundant initialization for '$symbol'. The initialized value is never used.",
+                CWE563,
+                inconclusive);
+}
+
 void CheckOther::redundantAssignmentInSwitchError(const Token *tok1, const Token* tok2, const std::string &var)
 {
     const std::list<const Token *> callstack = { tok1, tok2 };
diff --git a/lib/checkother.h b/lib/checkother.h
index aac4ec5c9..a3d31d6e6 100644
--- a/lib/checkother.h
+++ b/lib/checkother.h
@@ -230,6 +230,7 @@ private:
     void zerodivError(const Token *tok, const ValueFlow::Value *value);
     void nanInArithmeticExpressionError(const Token *tok);
     void redundantAssignmentError(const Token *tok1, const Token* tok2, const std::string& var, bool inconclusive);
+    void redundantInitializationError(const Token *tok1, const Token* tok2, const std::string& var, bool inconclusive);
     void redundantAssignmentInSwitchError(const Token *tok1, const Token *tok2, const std::string &var);
     void redundantCopyError(const Token *tok1, const Token* tok2, const std::string& var);
     void redundantCopyInSwitchError(const Token *tok1, const Token* tok2, const std::string &var);
@@ -285,7 +286,6 @@ private:
         //performance
         c.redundantCopyError(nullptr,  "varname");
         c.redundantCopyError(nullptr, nullptr, "var");
-        c.redundantAssignmentError(nullptr, nullptr, "var", false);
 
         // style/warning
         c.checkComparisonFunctionIsAlwaysTrueOrFalseError(nullptr, "isless","varName",false);
@@ -333,6 +333,8 @@ private:
         c.shadowError(nullptr, nullptr, "argument");
         c.constArgumentError(nullptr, nullptr, nullptr);
         c.comparePointersError(nullptr, nullptr, nullptr);
+        c.redundantAssignmentError(nullptr, nullptr, "var", false);
+        c.redundantInitializationError(nullptr, nullptr, "var", false);
 
         const std::vector<const Token *> nullvec;
         c.funcArgOrderDifferent("function", nullptr, nullptr, nullvec, nullvec);
diff --git a/test/testother.cpp b/test/testother.cpp
index eebe94da5..a7e09b6a2 100644
--- a/test/testother.cpp
+++ b/test/testother.cpp
@@ -171,6 +171,7 @@ private:
         TEST_CASE(redundantVarAssignment_after_switch);
         TEST_CASE(redundantVarAssignment_pointer);
         TEST_CASE(redundantVarAssignment_pointer_parameter);
+        TEST_CASE(redundantInitialization);
         TEST_CASE(redundantMemWrite);
 
         TEST_CASE(varFuncNullUB);
@@ -6548,6 +6549,32 @@ private:
         ASSERT_EQUALS("", errout.str());
     }
 
+    void redundantInitialization() {
+        check("void f() {\n"
+              "    int err = -ENOMEM;\n"
+              "    err = dostuff();\n"
+              "}");
+        ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:3]: (style) Redundant initialization for 'err'. The initialized value is never used.\n", errout.str());
+
+        check("void f() {\n"
+              "    struct S s = {1,2,3};\n"
+              "    s = dostuff();\n"
+              "}");
+        ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:3]: (style) Redundant initialization for 's'. The initialized value is never used.\n", errout.str());
+
+        check("void f() {\n"
+              "    int *p = NULL;\n"
+              "    p = dostuff();\n"
+              "}");
+        ASSERT_EQUALS("", errout.str());
+
+        check("void f() {\n"
+              "    struct S s = {0};\n"
+              "    s = dostuff();\n"
+              "}");
+        ASSERT_EQUALS("", errout.str());
+    }
+
     void redundantMemWrite() {
         return; // FIXME: temporary hack