[clang] Warn const integer-overflow of member in temporary struct bou…

…nd to rvalue reference (#117225) Fixes #46755 --------- Co-authored-by: Sirraide <[email protected]>
llvm · Nov 22, 2024 · ef20644 · ef20644
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diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
@@ -580,6 +580,9 @@ Improvements to Clang's diagnostics
 
 - Improved error recovery for function call arguments with trailing commas (#GH100921).
 
+- For an rvalue reference bound to a temporary struct with an integer member, Clang will detect constant integer overflow
+  in the initializer for the integer member (#GH46755).
+
 Improvements to Clang's time-trace
 ----------------------------------
 

diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
@@ -12048,7 +12048,8 @@ void Sema::CheckForIntOverflow (const Expr *E) {
              New && New->isArray()) {
       if (auto ArraySize = New->getArraySize())
         Exprs.push_back(*ArraySize);
-    }
+    } else if (const auto *MTE = dyn_cast<MaterializeTemporaryExpr>(OriginalE))
+      Exprs.push_back(MTE->getSubExpr());
   } while (!Exprs.empty());
 }
 

diff --git a/clang/test/SemaCXX/integer-overflow.cpp b/clang/test/SemaCXX/integer-overflow.cpp
@@ -246,4 +246,10 @@ int m() {
     return 0;
 }
 }
+
+namespace GH46755 {
+void f() {
+    struct { int v; } &&r = {512 * 1024 * 1024 * 1024}; // expected-warning {{overflow in expression; result is 0 with type 'int'}}
+}
+}
 #endif