From ccba934cb1dc847bdf169d4743b90c05a2e2b0d5 Mon Sep 17 00:00:00 2001
From: Alexander Mai <amai@users.sf.net>
Date: Thu, 17 Apr 2014 21:32:56 +0200
Subject: [PATCH] #5684 The scope of the variable 'p' can be reduced - But it
 can not.

---
 lib/checkother.cpp |  7 +++++++
 test/testother.cpp | 27 +++++++++++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/lib/checkother.cpp b/lib/checkother.cpp
index 3c7e7b3b6..932e478cd 100644
--- a/lib/checkother.cpp
+++ b/lib/checkother.cpp
@@ -1882,6 +1882,7 @@ bool CheckOther::checkInnerScope(const Token *tok, const Variable* var, bool& us
         }
     }
 
+    bool bFirstAssignment=false;
     for (; tok != end; tok = tok->next()) {
         if (tok->str() == "goto")
             return false;
@@ -1918,6 +1919,12 @@ bool CheckOther::checkInnerScope(const Token *tok, const Variable* var, bool& us
         if (Token::Match(tok, "& %varid%", var->declarationId())) // Taking address of variable
             return false;
 
+        if (Token::Match(tok, "%varid% = %any%", var->declarationId()))
+            bFirstAssignment = true;
+
+        if (!bFirstAssignment && Token::Match(tok, "* %varid%", var->declarationId())) // dereferencing means access to previous content
+            return false;
+
         if (Token::Match(tok, "= %varid%", var->declarationId()) && (var->isArray() || var->isPointer())) // Create a copy of array/pointer. Bailout, because the memory it points to might be necessary in outer scope
             return false;
 
diff --git a/test/testother.cpp b/test/testother.cpp
index 53bd28c87..7c52c7f78 100644
--- a/test/testother.cpp
+++ b/test/testother.cpp
@@ -83,6 +83,7 @@ private:
         TEST_CASE(varScope19);      // Ticket #4994
         TEST_CASE(varScope20);      // Ticket #5103
         TEST_CASE(varScope21);      // Ticket #5382
+        TEST_CASE(varScope22);      // Ticket #5684
 
         TEST_CASE(oldStylePointerCast);
         TEST_CASE(invalidPointerCast);
@@ -1256,6 +1257,32 @@ private:
         ASSERT_EQUALS("", errout.str());
     }
 
+    void varScope22() { // Ticket #5684 - "The scope of the variable 'p' can be reduced" - But it can not.
+        varScope("void foo() {\n"
+                 "   int* p( 42 );\n"
+                 "   int i = 0;\n"
+                 "   while ( i != 100 ) {\n"
+                 "      *p = i;\n"
+                 "      ++p;\n"
+                 "      ++i;\n"
+                 "   }\n"
+                 "}");
+        ASSERT_EQUALS("", errout.str());
+        // try to avoid an obvious false negative after applying the fix for the example above:
+        varScope("void foo() {\n"
+                 "   int* p( 42 );\n"
+                 "   int i = 0;\n"
+                 "   int dummy = 0;\n"
+                 "   while ( i != 100 ) {\n"
+                 "      p = & dummy;\n"
+                 "      *p = i;\n"
+                 "      ++p;\n"
+                 "      ++i;\n"
+                 "   }\n"
+                 "}");
+        ASSERT_EQUALS("[test.cpp:2]: (style) The scope of the variable 'p' can be reduced.\n", errout.str());
+    }
+
     void checkOldStylePointerCast(const char code[]) {
         // Clear the error buffer..
         errout.str("");