From 0197343e0c89c6c134157558ba58a136bb89ff36 Mon Sep 17 00:00:00 2001
From: Paul Fultz II <pfultz2@yahoo.com>
Date: Wed, 9 May 2018 02:06:49 -0500
Subject: [PATCH] Fix false positive when using null arithmetic with class type
 (#1214)

---
 lib/checknullpointer.cpp | 11 +++++++++--
 test/testnullpointer.cpp |  5 +++++
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/lib/checknullpointer.cpp b/lib/checknullpointer.cpp
index 19ee83679..11ee461cb 100644
--- a/lib/checknullpointer.cpp
+++ b/lib/checknullpointer.cpp
@@ -528,12 +528,19 @@ void CheckNullPointer::arithmetic()
             if (!Token::Match(tok, "-|+|+=|-=|++|--"))
                 continue;
             const Token *pointerOperand;
-            if (tok->astOperand1() && tok->astOperand1()->valueType() && tok->astOperand1()->valueType()->pointer != 0)
+            const Token *numericOperand;
+            if (tok->astOperand1() && tok->astOperand1()->valueType() && tok->astOperand1()->valueType()->pointer != 0) {
                 pointerOperand = tok->astOperand1();
-            else if (tok->astOperand2() && tok->astOperand2()->valueType() && tok->astOperand2()->valueType()->pointer != 0)
+                numericOperand = tok->astOperand2();
+            }
+            else if (tok->astOperand2() && tok->astOperand2()->valueType() && tok->astOperand2()->valueType()->pointer != 0) {
                 pointerOperand = tok->astOperand2();
+                numericOperand = tok->astOperand1();
+            }
             else
                 continue;
+            if (numericOperand && numericOperand->valueType() && !numericOperand->valueType()->isIntegral())
+                continue;
             MathLib::bigint checkValue = 0;
             // When using an assign op, the value read from
             // valueflow has already been updated, so instead of
diff --git a/test/testnullpointer.cpp b/test/testnullpointer.cpp
index 0982cc05e..8932fcf6b 100644
--- a/test/testnullpointer.cpp
+++ b/test/testnullpointer.cpp
@@ -2649,6 +2649,11 @@ private:
 
         check("int* f10() { int *x = NULL; return x++; } ");
         ASSERT_EQUALS("[test.cpp:1]: (error) Pointer addition with NULL pointer.\n", errout.str());
+
+        check("class foo {};\n"
+              "const char* get() const { return 0; }\n"
+              "void f(foo x) { if (get()) x += get(); }\n");
+        ASSERT_EQUALS("", errout.str());
     }
 };