From 71f9a7269f01f41f999827a0963ea365694155f3 Mon Sep 17 00:00:00 2001
From: chrchr-github <78114321+chrchr-github@users.noreply.github.com>
Date: Tue, 2 Aug 2022 21:43:18 +0200
Subject: [PATCH] Add test for #6541, #5475, avoid duplicate warning (#4335)

* Add test for #6541, avoid duplicate warning

* Add test for #5475

* Fix test
---
 lib/checknullpointer.cpp         |  3 ++-
 test/testincompletestatement.cpp | 10 ++++++++++
 test/testnullpointer.cpp         |  5 +++++
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/lib/checknullpointer.cpp b/lib/checknullpointer.cpp
index b10522b3a..4fbe58785 100644
--- a/lib/checknullpointer.cpp
+++ b/lib/checknullpointer.cpp
@@ -288,7 +288,8 @@ void CheckNullPointer::nullPointerByDeRefAndChec()
         if (Token::Match(tok, "%num%|%char%|%str%"))
             continue;
 
-        if (!isNullablePointer(tok, mSettings))
+        if (!isNullablePointer(tok, mSettings) ||
+            (tok->str() == "." && isNullablePointer(tok->astOperand2(), mSettings) && tok->astOperand2()->getValue(0))) // avoid duplicate warning
             continue;
 
         // Can pointer be NULL?
diff --git a/test/testincompletestatement.cpp b/test/testincompletestatement.cpp
index 755ae7983..37a017cde 100644
--- a/test/testincompletestatement.cpp
+++ b/test/testincompletestatement.cpp
@@ -667,6 +667,16 @@ private:
               "    *new int;\n"
               "}\n", /*inconclusive*/ true);
         ASSERT_EQUALS("[test.cpp:2]: (warning, inconclusive) Found suspicious operator '*', result is not used.\n", errout.str());
+
+        check("void f() {\n" // #5475
+              "    std::string(\"a\") + \"a\";\n"
+              "}\n"
+              "void f(std::string& a) {\n"
+              "    a.erase(3) + \"suf\";\n"
+              "}\n", /*inconclusive*/ true);
+        ASSERT_EQUALS("[test.cpp:2]: (warning, inconclusive) Found suspicious operator '+', result is not used.\n"
+                      "[test.cpp:5]: (warning, inconclusive) Found suspicious operator '+', result is not used.\n",
+                      errout.str());
     }
 
     void vardecl() {
diff --git a/test/testnullpointer.cpp b/test/testnullpointer.cpp
index 239be7e6e..45c13b658 100644
--- a/test/testnullpointer.cpp
+++ b/test/testnullpointer.cpp
@@ -993,6 +993,11 @@ private:
               "    if (p);\n"
               "}");
         ASSERT_EQUALS("", errout.str());
+
+        check("struct S { struct T { char c; } *p; };\n" // #6541
+              "char f(S* s) { return s->p ? 'a' : s->p->c; }\n");
+        ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:2]: (warning) Either the condition 's->p' is redundant or there is possible null pointer dereference: p.\n",
+                      errout.str());
     }
 
     void nullpointer5() {