From ac85b78e2a92c5fe23e597038c18841a1a18b4cc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <daniel.marjamaki@gmail.com>
Date: Sun, 9 Jul 2017 11:19:00 +0200
Subject: [PATCH] Fixed #5619 (false positive: unusedVariable - array accessed
 by pointer variable only)

---
 lib/checkunusedvar.cpp | 11 +++++++++--
 test/testunusedvar.cpp |  9 +++++++++
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/lib/checkunusedvar.cpp b/lib/checkunusedvar.cpp
index 26364e99c..e123f9269 100644
--- a/lib/checkunusedvar.cpp
+++ b/lib/checkunusedvar.cpp
@@ -594,9 +594,16 @@ static const Token* doAssignment(Variables &variables, const Token *tok, bool de
             } else { // not a local variable (or an unsupported local variable)
                 if (var1->_type == Variables::pointer && !dereference) {
                     // check if variable declaration is in this scope
-                    if (var1->_var->scope() == scope)
+                    if (var1->_var->scope() == scope) {
+                        // If variable is used in RHS then "use" variable
+                        for (const Token *rhs = tok; rhs && rhs->str() != ";"; rhs = rhs->next()) {
+                            if (rhs->varId() == varid1) {
+                                variables.use(varid1, tok);
+                                break;
+                            }
+                        }
                         variables.clearAliases(varid1);
-                    else {
+                    } else {
                         // no other assignment in this scope
                         if (var1->_assignments.find(scope) == var1->_assignments.end()) {
                             /**
diff --git a/test/testunusedvar.cpp b/test/testunusedvar.cpp
index bc2f2995e..817e2cbec 100644
--- a/test/testunusedvar.cpp
+++ b/test/testunusedvar.cpp
@@ -116,6 +116,7 @@ private:
         TEST_CASE(localvaralias11); // ticket #4423 - iterator
         TEST_CASE(localvaralias12); // ticket #4394
         TEST_CASE(localvaralias13); // ticket #4487
+        TEST_CASE(localvaralias14); // ticket #5619
         TEST_CASE(localvarasm);
         TEST_CASE(localvarstatic);
         TEST_CASE(localvarextern);
@@ -3008,6 +3009,14 @@ private:
         TODO_ASSERT_EQUALS("a is assigned value that is never used", "", errout.str());
     }
 
+    void localvaralias14() { // #5619
+        functionVariableUsage("void f() {\n"
+                              "    char a[4], *p=a;\n"
+                              "    p = dostuff(p);\n"
+                              "}");
+        TODO_ASSERT_EQUALS("p is assigned a value that is never used", "", errout.str());
+    }
+
     void localvarasm() {
         functionVariableUsage("void foo(int &b)\n"
                               "{\n"