From d3d40fd599465461e4b1bd63e3fed2170abfe225 Mon Sep 17 00:00:00 2001
From: chrchr-github <78114321+chrchr-github@users.noreply.github.com>
Date: Mon, 14 Mar 2022 14:14:32 +0100
Subject: [PATCH] Fix #10868/#10869 FN: constStatement, handle unused character
 constants (#3898)

* Fix #10868 FN: constStatement, handle unused character constants

* simpleMatch

* Fix #10869 FN: constStatement

* Format
---
 lib/checkother.cpp               | 13 +++++++---
 test/testincompletestatement.cpp | 43 ++++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+), 3 deletions(-)

diff --git a/lib/checkother.cpp b/lib/checkother.cpp
index a928358bc..814b8edd9 100644
--- a/lib/checkother.cpp
+++ b/lib/checkother.cpp
@@ -1763,7 +1763,7 @@ static bool isConstStatement(const Token *tok, bool cpp)
         return isWithoutSideEffects(cpp, tok->astOperand1()) && isConstStatement(tok->astOperand1(), cpp);
     if (Token::Match(tok, "( %type%"))
         return isConstStatement(tok->astOperand1(), cpp);
-    if (Token::simpleMatch(tok, ","))
+    if (Token::Match(tok, ",|."))
         return isConstStatement(tok->astOperand2(), cpp);
     if (Token::simpleMatch(tok, "?") && Token::simpleMatch(tok->astOperand2(), ":")) // ternary operator
         return isConstStatement(tok->astOperand1(), cpp) && isConstStatement(tok->astOperand2()->astOperand1(), cpp) && isConstStatement(tok->astOperand2()->astOperand2(), cpp);
@@ -1838,7 +1838,10 @@ void CheckOther::checkIncompleteStatement()
 
         const Token *rtok = nextAfterAstRightmostLeaf(tok);
         if (!Token::simpleMatch(tok->astParent(), ";") && !Token::simpleMatch(rtok, ";") &&
-            !Token::Match(tok->previous(), ";|}|{ %any% ;") && !(mTokenizer->isCPP() && tok->isCast() && !tok->astParent()))
+            !Token::Match(tok->previous(), ";|}|{ %any% ;") &&
+            !(mTokenizer->isCPP() && tok->isCast() && !tok->astParent()) &&
+            !Token::simpleMatch(tok->tokAt(-2), "for (") &&
+            !Token::Match(tok->tokAt(-1), "%var% ["))
             continue;
         // Skip statement expressions
         if (Token::simpleMatch(rtok, "; } )"))
@@ -1869,12 +1872,14 @@ void CheckOther::constStatementError(const Token *tok, const std::string &type,
         msg = "Found suspicious operator '" + tok->str() + "'";
     else if (Token::Match(tok, "%var%"))
         msg = "Unused variable value '" + tok->str() + "'";
-    else if (Token::Match(valueTok, "%str%|%num%|%bool%")) {
+    else if (Token::Match(valueTok, "%str%|%num%|%bool%|%char%")) {
         std::string typeStr("string");
         if (valueTok->isNumber())
             typeStr = "numeric";
         else if (valueTok->isBoolean())
             typeStr = "bool";
+        else if (valueTok->tokType() == Token::eChar)
+            typeStr = "character";
         msg = "Redundant code: Found a statement that begins with " + typeStr + " constant.";
     }
     else if (!tok)
@@ -1885,6 +1890,8 @@ void CheckOther::constStatementError(const Token *tok, const std::string &type,
     }
     else if (tok->str() == "?" && tok->tokType() == Token::Type::eExtendedOp)
         msg = "Redundant code: Found unused result of ternary operator.";
+    else if (tok->str() == "." && tok->tokType() == Token::Type::eOther)
+        msg = "Redundant code: Found unused member access.";
     else {
         reportError(tok, Severity::debug, "debug", "constStatementError not handled.");
         return;
diff --git a/test/testincompletestatement.cpp b/test/testincompletestatement.cpp
index c16b713a2..7bac14db0 100644
--- a/test/testincompletestatement.cpp
+++ b/test/testincompletestatement.cpp
@@ -429,6 +429,49 @@ private:
               "    b = (b ? true : false);\n"
               "}\n");
         ASSERT_EQUALS("", errout.str());
+
+        check("void f(int i) {\n"
+              "    for (i; ;) {}\n"
+              "    for ((long)i; ;) {}\n"
+              "    for (1; ;) {}\n"
+              "    for (true; ;) {}\n"
+              "    for ('a'; ;) {}\n"
+              "    for (L'b'; ;) {}\n"
+              "    for (\"x\"; ;) {}\n"
+              "    for (L\"y\"; ;) {}\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:2]: (warning) Unused variable value 'i'\n"
+                      "[test.cpp:3]: (warning) Redundant code: Found unused cast of expression 'i'.\n"
+                      "[test.cpp:4]: (warning) Redundant code: Found a statement that begins with numeric constant.\n"
+                      "[test.cpp:5]: (warning) Redundant code: Found a statement that begins with bool constant.\n"
+                      "[test.cpp:6]: (warning) Redundant code: Found a statement that begins with character constant.\n"
+                      "[test.cpp:7]: (warning) Redundant code: Found a statement that begins with character constant.\n"
+                      "[test.cpp:8]: (warning) Redundant code: Found a statement that begins with string constant.\n"
+                      "[test.cpp:9]: (warning) Redundant code: Found a statement that begins with string constant.\n",
+                      errout.str());
+
+        check("struct S { bool b{}; };\n"
+              "struct T {\n"
+              "    S s[2];\n"
+              "    void g();\n"
+              "};\n"
+              "void f(const S& r, const S* p) {\n"
+              "	r.b;\n"
+              "	p->b;\n"
+              "	S s;\n"
+              "	(s.b);\n"
+              "	T t, u[2];\n"
+              "	t.s[1].b;\n"
+              "	t.g();\n"
+              "	u[0].g();\n"
+              "	u[1].s[0].b;\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:7]: (warning) Redundant code: Found unused member access.\n"
+                      "[test.cpp:8]: (warning) Redundant code: Found unused member access.\n"
+                      "[test.cpp:10]: (warning) Redundant code: Found unused member access.\n"
+                      "[test.cpp:12]: (warning) Redundant code: Found unused member access.\n"
+                      "[test.cpp:15]: (warning) Redundant code: Found unused member access.\n",
+                      errout.str());
     }
 
     void vardecl() {