[PATCH] D146801: [clang] Fix consteval initializers of temporaries

[Mariya Podchishchaeva via Phabricator via cfe-commits]

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When a potential immediate invocation is met, it is immediately wrapped by a
`ConstantExpr`. There is also a TreeTransform that removes this `ConstantExpr`
wrapper when corresponding expression evaluation context is popped.
So, in case initializer was an immediate invocation, `CXXTemporaryObjectExpr`
was wrapped by a `ConstantExpr`, and that caused additional unnecessary
`CXXFunctionalCastExpr` to be added, which later confused the TreeTransform
that rebuilds immediate invocations, so it was adding unnecessary
constructor call.

Fixes https://github.com/llvm/llvm-project/issues/60286


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D146801

Files:
  clang/lib/Sema/SemaExprCXX.cpp
  clang/test/SemaCXX/cxx2a-consteval.cpp


Index: clang/test/SemaCXX/cxx2a-consteval.cpp
===================================================================
--- clang/test/SemaCXX/cxx2a-consteval.cpp
+++ clang/test/SemaCXX/cxx2a-consteval.cpp
@@ -1050,3 +1050,18 @@
 
 }
 }
+
+namespace GH60286 {
+
+struct A {
+  int i = 0;
+
+  consteval A() {}
+  A(const A&) { i = 1; }
+  consteval int f() { return i; }
+};
+
+constexpr auto B = A{A{}}.f();
+static_assert(B == 0);
+
+}
Index: clang/lib/Sema/SemaExprCXX.cpp
===================================================================
--- clang/lib/Sema/SemaExprCXX.cpp
+++ clang/lib/Sema/SemaExprCXX.cpp
@@ -1590,6 +1590,9 @@
   Expr *Inner = Result.get();
   if (CXXBindTemporaryExpr *BTE = dyn_cast_or_null<CXXBindTemporaryExpr>(Inner))
     Inner = BTE->getSubExpr();
+  if (ConstantExpr *CE = dyn_cast_or_null<ConstantExpr>(Inner))
+    if (CE->isImmediateInvocation())
+      Inner = CE->getSubExpr();
   if (!isa<CXXTemporaryObjectExpr>(Inner) &&
       !isa<CXXScalarValueInitExpr>(Inner)) {
     // If we created a CXXTemporaryObjectExpr, that node also represents the


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