From 0767284ca13ffd660d1690b54b31787ba59ed5da Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <daniel.marjamaki@gmail.com>
Date: Mon, 25 Jul 2016 07:35:33 +0200
Subject: [PATCH] Fixed #7630 (FP: dead store, modifying array, index var
 modified)

---
 lib/checkother.cpp | 19 +++++++++++++++++--
 test/testother.cpp | 15 +++++++++++++++
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/lib/checkother.cpp b/lib/checkother.cpp
index 919157ec4..0b295163b 100644
--- a/lib/checkother.cpp
+++ b/lib/checkother.cpp
@@ -501,9 +501,24 @@ void CheckOther::checkRedundantAssignment()
             } else if (tok->tokType() == Token::eVariable && !Token::Match(tok, "%name% (")) {
                 const Token *eq = nullptr;
                 for (const Token *tok2 = tok; tok2; tok2 = tok2->next()) {
-                    if (Token::Match(tok2, "[([]"))
+                    if (Token::Match(tok2, "[([]")) {
+                        // bail out if there is a variable in rhs - we only track 1 variable
+                        bool bailout = false;
+                        for (const Token *tok3 = tok2->link(); tok3 != tok2; tok3 = tok3->previous()) {
+                            if (tok3->varId()) {
+                                if (!tok3->variable())
+                                    bailout = true;
+                                else {
+                                    const Variable *var = tok3->variable();
+                                    if (!var->isConst() || var->isReference() || var->isPointer())
+                                        bailout = true;
+                                }
+                            }
+                        }
+                        if (bailout)
+                            break;
                         tok2 = tok2->link();
-                    else if (Token::Match(tok2, "[)];,]"))
+                    } else if (Token::Match(tok2, "[)];,]"))
                         break;
                     else if (tok2->str() == "=") {
                         eq = tok2;
diff --git a/test/testother.cpp b/test/testother.cpp
index d9043f825..b194ff7b7 100644
--- a/test/testother.cpp
+++ b/test/testother.cpp
@@ -4577,6 +4577,21 @@ private:
               "}", nullptr, false, false, false);
         ASSERT_EQUALS("[test.cpp:3] -> [test.cpp:4]: (style) Variable 'i[2]' is reassigned a value before the old one has been used.\n", errout.str());
 
+        check("void f(int x) {\n"
+              "    int i[10];\n"
+              "    i[x] = 1;\n"
+              "    x=1;\n"
+              "    i[x] = 1;\n"
+              "}", nullptr, false, false, false);
+        ASSERT_EQUALS("", errout.str());
+
+        check("void f(const int x) {\n"
+              "    int i[10];\n"
+              "    i[x] = 1;\n"
+              "    i[x] = 1;\n"
+              "}", nullptr, false, false, false);
+        ASSERT_EQUALS("[test.cpp:3] -> [test.cpp:4]: (style) Variable 'i[x]' is reassigned a value before the old one has been used.\n", errout.str());
+
         // Testing different types
         check("void f() {\n"
               "    Foo& bar = foo();\n"