From 55c2b75c2e0481db4779153f2792e7cf3f5cfb94 Mon Sep 17 00:00:00 2001
From: chrchr-github <78114321+chrchr-github@users.noreply.github.com>
Date: Fri, 1 Dec 2023 17:42:27 +0100
Subject: [PATCH] Fix #6933 FN uninitvar with POD struct and STL types (#5713)

Co-authored-by: chrchr-github <chrchr@github>
---
 lib/astutils.cpp       |  5 +++++
 test/cfg/qt.cpp        |  7 +++++++
 test/cfg/std.cpp       |  2 +-
 test/testuninitvar.cpp | 18 ++++++++++++++++++
 4 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/lib/astutils.cpp b/lib/astutils.cpp
index 2da5f3f21..62a616ee6 100644
--- a/lib/astutils.cpp
+++ b/lib/astutils.cpp
@@ -3257,6 +3257,11 @@ static ExprUsage getFunctionUsage(const Token* tok, int indirect, const Settings
         return ExprUsage::Used;
     } else if (ftok->str() == "{") {
         return indirect == 0 ? ExprUsage::Used : ExprUsage::Inconclusive;
+    } else if (ftok->variable() && ftok == ftok->variable()->nameToken()) { // variable init/constructor call
+        if (ftok->variable()->type() && ftok->variable()->type()->needInitialization == Type::NeedInitialization::True)
+            return ExprUsage::Used;
+        if (ftok->variable()->isStlType() || (ftok->variable()->valueType() && ftok->variable()->valueType()->container)) // STL types or containers don't initialize external variables
+            return ExprUsage::Used;
     } else {
         const bool isnullbad = settings->library.isnullargbad(ftok, argnr + 1);
         if (indirect == 0 && astIsPointer(tok) && !addressOf && isnullbad)
diff --git a/test/cfg/qt.cpp b/test/cfg/qt.cpp
index 63ccf3b1d..46310e321 100644
--- a/test/cfg/qt.cpp
+++ b/test/cfg/qt.cpp
@@ -321,6 +321,13 @@ void duplicateExpression_QString_Compare(QString style) //#8723
     {}
 }
 
+void QVector_uninit()
+{
+    int i;
+    // cppcheck-suppress [uninitvar, unreadVariable]
+    QVector<int> v(i);
+}
+
 void QStack1(QStack<int> intStackArg)
 {
     for (int i = 0; i <= intStackArg.size(); ++i) {
diff --git a/test/cfg/std.cpp b/test/cfg/std.cpp
index b0926a0ee..b8305bb62 100644
--- a/test/cfg/std.cpp
+++ b/test/cfg/std.cpp
@@ -1043,8 +1043,8 @@ void uninitvar_isxdigit(void)
 void uninitvar_proj(void)
 {
     double d;
+    // cppcheck-suppress uninitvar
     const std::complex<double> dc(d,d);
-    // TODO cppcheck-suppress uninitvar
     (void)std::proj(dc);
 }
 
diff --git a/test/testuninitvar.cpp b/test/testuninitvar.cpp
index 37b2100f5..ff6490afb 100644
--- a/test/testuninitvar.cpp
+++ b/test/testuninitvar.cpp
@@ -7251,6 +7251,24 @@ private:
                       "[test.cpp:23]: (error) Uninitialized variable: s.t.j\n"
                       "[test.cpp:27]: (error) Uninitialized variable: s.t.j\n",
                       errout.str());
+
+        valueFlowUninit("struct S { int x; };\n"
+                        "void f() {\n"
+                        "    int i;\n"
+                        "    S s(i);\n"
+                        "}\n"
+                        "void g() {\n"
+                        "    int i;\n"
+                        "    S t{ i };\n"
+                        "}\n"
+                        "void h() {\n"
+                        "    int i;\n"
+                        "    std::vector<int> v(i);\n"
+                        "}\n");
+        ASSERT_EQUALS("[test.cpp:4]: (error) Uninitialized variable: i\n"
+                      "[test.cpp:8]: (error) Uninitialized variable: i\n"
+                      "[test.cpp:12]: (error) Uninitialized variable: i\n",
+                      errout.str());
     }
 
     void uninitvar_memberfunction() {