From affd03f1d6219591aff43509626d85e9e7df9fc2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <daniel.marjamaki@gmail.com>
Date: Mon, 26 Nov 2018 11:16:50 +0100
Subject: [PATCH] Minor tweak for redundantVariableAssignment

---
 lib/checkother.cpp | 20 ++++++++++++++++----
 test/testother.cpp | 14 ++++----------
 2 files changed, 20 insertions(+), 14 deletions(-)

diff --git a/lib/checkother.cpp b/lib/checkother.cpp
index 434ecc4e6..a6d032a19 100644
--- a/lib/checkother.cpp
+++ b/lib/checkother.cpp
@@ -560,13 +560,25 @@ void CheckOther::checkRedundantAssignment()
                 if (tok->astParent())
                     continue;
 
-                // Do not warn about redundant initialization
+                // Do not warn about redundant initialization when rhs is trivial
                 // TODO : do not simplify the variable declarations
-                if (Token::Match(tok->tokAt(-3), "%var% ; %var% =") && tok->previous()->variable() && tok->previous()->variable()->nameToken() == tok->tokAt(-3))
-                    continue;
+                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()) {
+                    bool trivial = true;
+                    visitAstNodes(tok->astOperand2(),
+                    [&](const Token *rhs) {
+                        if (Token::Match(rhs, "%str%|%num%|%name%"))
+                            return ChildrenToVisit::op1_and_op2;
+                        if (rhs->str() == "(" && !rhs->previous()->isName())
+                            return ChildrenToVisit::op1_and_op2;
+                        trivial = false;
+                        return ChildrenToVisit::done;
+                    });
+                    if (trivial)
+                        continue;
+                }
 
                 // Do not warn about assignment with 0 / NULL
-                if (Token::simpleMatch(tok->astOperand2(), "0"))
+                if (Token::Match(tok->astOperand2(), "0|NULL|nullptr"))
                     continue;
 
                 if (tok->astOperand1()->variable() && tok->astOperand1()->variable()->isReference())
diff --git a/test/testother.cpp b/test/testother.cpp
index 04d289e47..0bca64f58 100644
--- a/test/testother.cpp
+++ b/test/testother.cpp
@@ -5602,15 +5602,13 @@ private:
 
         check("void f() {\n"
               "    int i;\n"
-              "    dostuff();\n"
               "    i = 1;\n"
               "    i = 1;\n"
               "}");
-        ASSERT_EQUALS("[test.cpp:4] -> [test.cpp:5]: (style) Variable 'i' is reassigned a value before the old one has been used.\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:3] -> [test.cpp:4]: (style) Variable 'i' is reassigned a value before the old one has been used.\n", errout.str());
 
         check("void f() {\n"
               "    static int i;\n"
-              "    dostuff();\n"
               "    i = 1;\n"
               "    i = 1;\n"
               "}");
@@ -5686,12 +5684,11 @@ private:
 
         check("void f() {\n"
               "    int i;\n"
-              "    dostuff();\n"
               "    i = 1;\n"
               "    bar();\n"
               "    i = 1;\n"
               "}");
-        ASSERT_EQUALS("[test.cpp:4] -> [test.cpp:6]: (style) Variable 'i' is reassigned a value before the old one has been used.\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:3] -> [test.cpp:5]: (style) Variable 'i' is reassigned a value before the old one has been used.\n", errout.str());
 
         check("void bar(int i) {}\n"
               "void f(int i) {\n"
@@ -5778,17 +5775,15 @@ private:
         // from #3103 (avoid a false negative)
         check("int foo(){\n"
               "    int x;\n"
-              "    dostuff();\n"
               "    x = 1;\n"
               "    x = 1;\n"
               "    return x + 1;\n"
               "}");
-        ASSERT_EQUALS("[test.cpp:4] -> [test.cpp:5]: (style) Variable 'x' is reassigned a value before the old one has been used.\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:3] -> [test.cpp:4]: (style) Variable 'x' is reassigned a value before the old one has been used.\n", errout.str());
 
         // from #3103 (avoid a false positive)
         check("int foo(){\n"
               "    int x;\n"
-              "    dostuff();\n"
               "    x = 1;\n"
               "    if (y)\n" // <-- cppcheck does not know anything about 'y'
               "        x = 2;\n"
@@ -6016,11 +6011,10 @@ private:
         check("class C { void operator=(int x); };\n" // #8368 - assignment operator might have side effects => inconclusive
               "void f() {\n"
               "    C c;\n"
-              "    dostuff();\n"
               "    c = x;\n"
               "    c = x;\n"
               "}");
-        ASSERT_EQUALS("[test.cpp:5] -> [test.cpp:6]: (style, inconclusive) Variable 'c' is reassigned a value before the old one has been used if variable is no semaphore variable.\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:4] -> [test.cpp:5]: (style, inconclusive) Variable 'c' is reassigned a value before the old one has been used if variable is no semaphore variable.\n", errout.str());
     }
 
     void redundantVarAssignment_stackoverflow() {