From 418eb43d4587b833df66c95257b1f277e8931f64 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <daniel.marjamaki@gmail.com>
Date: Sat, 23 Mar 2019 19:00:55 +0100
Subject: [PATCH] Fixed #9032 (False-positive detection of reassigned value
 before used for pointer parameter)

---
 lib/astutils.cpp   | 10 +++++++---
 test/testother.cpp | 10 ++++++++++
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/lib/astutils.cpp b/lib/astutils.cpp
index e3f3fbe6d..7d16414e6 100644
--- a/lib/astutils.cpp
+++ b/lib/astutils.cpp
@@ -1122,9 +1122,9 @@ bool isConstVarExpression(const Token *tok)
     return false;
 }
 
-static bool nonLocal(const Variable* var)
+static bool nonLocal(const Variable* var, bool deref)
 {
-    return !var || (!var->isLocal() && !var->isArgument()) || var->isStatic() || var->isReference() || var->isExtern();
+    return !var || (!var->isLocal() && !var->isArgument()) || (deref && var->isArgument() && var->isPointer()) || var->isStatic() || var->isReference() || var->isExtern();
 }
 
 static bool hasFunctionCall(const Token *tok)
@@ -1175,6 +1175,9 @@ struct FwdAnalysis::Result FwdAnalysis::checkRecursive(const Token *expr, const
                     return Result(Result::Type::READ);
             }
 
+            if (!local && mWhat == What::Reassign)
+                return Result(Result::Type::BAILOUT);
+
             return Result(Result::Type::RETURN);
         }
 
@@ -1391,7 +1394,8 @@ FwdAnalysis::Result FwdAnalysis::check(const Token *expr, const Token *startToke
                 const Variable *var = tok->variable();
                 if (var && var->isReference() && var->isLocal() && Token::Match(var->nameToken(), "%var% [=(]") && !isGlobalData(var->nameToken()->next()->astOperand2()))
                     return ChildrenToVisit::none;
-                local &= !nonLocal(tok->variable());
+                const bool deref = tok->astParent() && (tok->astParent()->isUnaryOp("*") || (tok->astParent()->str() == "[" && tok == tok->astParent()->astOperand1()));
+                local &= !nonLocal(tok->variable(), deref);
             }
         }
         return ChildrenToVisit::op1_and_op2;
diff --git a/test/testother.cpp b/test/testother.cpp
index 71758d708..9c3044b11 100644
--- a/test/testother.cpp
+++ b/test/testother.cpp
@@ -166,6 +166,7 @@ private:
         TEST_CASE(redundantVarAssignment_lambda);
         TEST_CASE(redundantVarAssignment_for);
         TEST_CASE(redundantVarAssignment_after_switch);
+        TEST_CASE(redundantVarAssignment_pointer_parameter);
         TEST_CASE(redundantMemWrite);
 
         TEST_CASE(varFuncNullUB);
@@ -6105,6 +6106,15 @@ private:
         ASSERT_EQUALS("[test.cpp:5] -> [test.cpp:8]: (style) Variable 'ret' is reassigned a value before the old one has been used.\n", errout.str());
     }
 
+    void redundantVarAssignment_pointer_parameter() {
+        check("void f(int *p) {\n"
+              "    *p = 1;\n"
+              "    if (condition) return;\n"
+              "    *p = 2;\n"
+              "}");
+        ASSERT_EQUALS("", errout.str());
+    }
+
     void redundantMemWrite() {
         return; // FIXME: temporary hack