From 5f6ef537aa9abefbc568538ed671e263cc0261d0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <daniel.marjamaki@gmail.com>
Date: Wed, 14 May 2025 17:17:44 +0200
Subject: [PATCH] Fix #13847 (simplifyTypedef should not simplify )

---
 lib/tokenize.cpp             | 33 +++++----------------------------
 lib/tokenize.h               |  3 ---
 test/testsimplifytypedef.cpp | 10 +++++++++-
 test/testtokenize.cpp        | 13 +++++++++++++
 4 files changed, 27 insertions(+), 32 deletions(-)

diff --git a/lib/tokenize.cpp b/lib/tokenize.cpp
index d5aa81172f8..ce36f8ff323 100644
--- a/lib/tokenize.cpp
+++ b/lib/tokenize.cpp
@@ -503,31 +503,6 @@ Token *Tokenizer::processFunc(Token *tok2, bool inOperator)
     return const_cast<Token*>(processFunc(const_cast<const Token*>(tok2), inOperator));
 }
 
-void Tokenizer::simplifyUsingToTypedef()
-{
-    if (!isCPP() || mSettings.standards.cpp < Standards::CPP11)
-        return;
-
-    for (Token *tok = list.front(); tok; tok = tok->next()) {
-        // using a::b;  =>   typedef  a::b  b;
-        if ((Token::Match(tok, "[;{}] using %name% :: %name% ::|;") && !tok->tokAt(2)->isKeyword()) ||
-            (Token::Match(tok, "[;{}] using :: %name% :: %name% ::|;") && !tok->tokAt(3)->isKeyword())) {
-            Token *endtok = tok->tokAt(5);
-            if (Token::Match(endtok, "%name%"))
-                endtok = endtok->next();
-            while (Token::Match(endtok, ":: %name%"))
-                endtok = endtok->tokAt(2);
-            if (endtok && endtok->str() == ";") {
-                if (endtok->strAt(-1) == endtok->strAt(-3))
-                    continue;
-                tok->next()->str("typedef");
-                endtok = endtok->previous();
-                endtok->insertToken(endtok->str());
-            }
-        }
-    }
-}
-
 void Tokenizer::simplifyTypedefLHS()
 {
     if (!list.front())
@@ -1157,9 +1132,6 @@ void Tokenizer::simplifyTypedefCpp()
     // add global namespace
     std::vector<Space> spaceInfo(1);
 
-    // Convert "using a::b;" to corresponding typedef statements
-    simplifyUsingToTypedef();
-
     const std::time_t maxTime = mSettings.typedefMaxTime > 0 ? std::time(nullptr) + mSettings.typedefMaxTime: 0;
     const bool doProgress = (mSettings.reportProgress != -1) && !list.getFiles().empty();
 
@@ -1975,6 +1947,11 @@ void Tokenizer::simplifyTypedefCpp()
                     }
                     if (Token::Match(tok2->tokAt(-1), "class|struct|union") && tok2->strAt(-1) == typeStart->str())
                         tok2->deletePrevious();
+
+                    if (cpp && Token::Match(tok2->previous(), "using %name% ::|;")) {
+                        tok2->previous()->str("typedef");
+                        tok2->insertToken(tok2->str());
+                    }
                     tok2->str(typeStart->str());
 
                     // restore qualification if it was removed
diff --git a/lib/tokenize.h b/lib/tokenize.h
index fab0a348cf3..9770ec2d288 100644
--- a/lib/tokenize.h
+++ b/lib/tokenize.h
@@ -218,9 +218,6 @@ class CPPCHECKLIB Tokenizer {
      */
     Token * simplifyAddBracesPair(Token *tok, bool commandWithCondition);
 
-    // Convert "using ...;" to corresponding typedef
-    void simplifyUsingToTypedef();
-
     /**
      * typedef A mytype;
      * mytype c;
diff --git a/test/testsimplifytypedef.cpp b/test/testsimplifytypedef.cpp
index 90146a46d2e..f77ad41889e 100644
--- a/test/testsimplifytypedef.cpp
+++ b/test/testsimplifytypedef.cpp
@@ -249,8 +249,8 @@ class TestSimplifyTypedef : public TestFixture {
         TEST_CASE(simplifyTypedefTokenColumn3);
 
         TEST_CASE(typedefInfo1);
-
         TEST_CASE(typedefInfo2);
+        TEST_CASE(typedefInfo3);
     }
 
     struct TokOptions
@@ -4562,6 +4562,14 @@ class TestSimplifyTypedef : public TestFixture {
                       "    <info name=\"pfp16\" file=\"file.c\" line=\"4\" column=\"20\" used=\"0\" isFunctionPointer=\"1\"/>\n"
                       "  </typedef-info>\n",xml);
     }
+
+    void typedefInfo3() {
+        const std::string xml = dumpTypedefInfo("int main() {\n"
+                                                "     using x::a;\n"
+                                                "     b = a + 2;\n"
+                                                "}\n");
+        ASSERT_EQUALS("",xml);
+    }
 };
 
 REGISTER_TEST(TestSimplifyTypedef)
diff --git a/test/testtokenize.cpp b/test/testtokenize.cpp
index 21302952660..09e8039daa6 100644
--- a/test/testtokenize.cpp
+++ b/test/testtokenize.cpp
@@ -80,6 +80,7 @@ class TestTokenizer : public TestFixture {
         TEST_CASE(tokenize38);  // #9569
         TEST_CASE(tokenize39);  // #9771
         TEST_CASE(tokenize40);  // #13181
+        TEST_CASE(tokenize41);  // #13847
 
         TEST_CASE(validate);
 
@@ -860,6 +861,18 @@ class TestTokenizer : public TestFixture {
         ASSERT_EQUALS("", errout_str());
     }
 
+    void tokenize41() { // #13847
+        const char code[] = "int main() {\n"
+                            "     using x::a;\n"
+                            "     b = a + 2;\n"
+                            "}\n";
+        ASSERT_EQUALS("int main ( ) {\n"
+                      "\n"
+                      "b = x :: a + 2 ;\n"
+                      "}", tokenizeAndStringify(code));
+        (void)errout_str();
+    }
+
     void validate() {
         // C++ code in C file
         ASSERT_THROW_INTERNAL(tokenizeAndStringify(";using namespace std;",false,Platform::Type::Native,false), SYNTAX);