From 034140e7e1c679584aa7399cd6141b1c88ae8d98 Mon Sep 17 00:00:00 2001
From: chrchr-github <78114321+chrchr-github@users.noreply.github.com>
Date: Wed, 27 Apr 2022 19:52:56 +0200
Subject: [PATCH] Fix #10991 FN: Redundant pointer operation (#4054)

---
 lib/checkother.cpp | 19 ++++++++++++-------
 lib/checkother.h   |  4 ++--
 test/testother.cpp | 10 ++++++++++
 3 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/lib/checkother.cpp b/lib/checkother.cpp
index 487a18e56..16c74f5e2 100644
--- a/lib/checkother.cpp
+++ b/lib/checkother.cpp
@@ -2941,7 +2941,12 @@ void CheckOther::checkRedundantPointerOp()
         if (tok->isExpandedMacro() && tok->str() == "(")
             tok = tok->link();
 
-        if (!tok->isUnaryOp("&") || !tok->astOperand1()->isUnaryOp("*"))
+        bool addressOfDeref{};
+        if (tok->isUnaryOp("&") && tok->astOperand1()->isUnaryOp("*"))
+            addressOfDeref = true;
+        else if (tok->isUnaryOp("*") && tok->astOperand1()->isUnaryOp("&"))
+            addressOfDeref = false;
+        else
             continue;
 
         // variable
@@ -2950,18 +2955,18 @@ void CheckOther::checkRedundantPointerOp()
             continue;
 
         const Variable *var = varTok->variable();
-        if (!var || !var->isPointer())
+        if (!var || (addressOfDeref && !var->isPointer()))
             continue;
 
-        redundantPointerOpError(tok, var->name(), false);
+        redundantPointerOpError(tok, var->name(), false, addressOfDeref);
     }
 }
 
-void CheckOther::redundantPointerOpError(const Token* tok, const std::string &varname, bool inconclusive)
+void CheckOther::redundantPointerOpError(const Token* tok, const std::string &varname, bool inconclusive, bool addressOfDeref)
 {
-    reportError(tok, Severity::style, "redundantPointerOp",
-                "$symbol:" + varname + "\n"
-                "Redundant pointer operation on '$symbol' - it's already a pointer.", CWE398, inconclusive ? Certainty::inconclusive : Certainty::normal);
+    std::string msg = "$symbol:" + varname + "\nRedundant pointer operation on '$symbol' - it's already a ";
+    msg += addressOfDeref ? "pointer." : "variable.";
+    reportError(tok, Severity::style, "redundantPointerOp", msg, CWE398, inconclusive ? Certainty::inconclusive : Certainty::normal);
 }
 
 void CheckOther::checkInterlockedDecrement()
diff --git a/lib/checkother.h b/lib/checkother.h
index 86da1db08..8f8403526 100644
--- a/lib/checkother.h
+++ b/lib/checkother.h
@@ -275,7 +275,7 @@ private:
     void incompleteArrayFillError(const Token* tok, const std::string& buffer, const std::string& function, bool boolean);
     void varFuncNullUBError(const Token *tok);
     void commaSeparatedReturnError(const Token *tok);
-    void redundantPointerOpError(const Token* tok, const std::string& varname, bool inconclusive);
+    void redundantPointerOpError(const Token* tok, const std::string& varname, bool inconclusive, bool addressOfDeref);
     void raceAfterInterlockedDecrementError(const Token* tok);
     void unusedLabelError(const Token* tok, bool inSwitch, bool hasIfdef);
     void unknownEvaluationOrder(const Token* tok);
@@ -343,7 +343,7 @@ private:
         c.varFuncNullUBError(nullptr);
         c.nanInArithmeticExpressionError(nullptr);
         c.commaSeparatedReturnError(nullptr);
-        c.redundantPointerOpError(nullptr,  "varname", false);
+        c.redundantPointerOpError(nullptr,  "varname", false, /*addressOfDeref*/ true);
         c.unusedLabelError(nullptr, false, false);
         c.unusedLabelError(nullptr, false, true);
         c.unusedLabelError(nullptr, true, false);
diff --git a/test/testother.cpp b/test/testother.cpp
index 23c987333..06e13e0b2 100644
--- a/test/testother.cpp
+++ b/test/testother.cpp
@@ -8764,6 +8764,16 @@ private:
               "}\n", nullptr, false, true);
         ASSERT_EQUALS("[test.cpp:2]: (style) Redundant pointer operation on 'y' - it's already a pointer.\n", errout.str());
 
+        check("int f() {\n" // #10991
+              "    int value = 4;\n"
+              "    int result1 = *(&value);\n"
+              "    int result2 = *&value;\n"
+              "    return result1 + result2;\n"
+              "}\n", nullptr, false, true);
+        ASSERT_EQUALS("[test.cpp:3]: (style) Redundant pointer operation on 'value' - it's already a variable.\n"
+                      "[test.cpp:4]: (style) Redundant pointer operation on 'value' - it's already a variable.\n",
+                      errout.str());
+
         // no warning for bitwise AND
         check("void f(const int *b) {\n"
               "    int x = 0x20 & *b;\n"