[PATCH] D144866: [clang] Fix aggregate initialization inside lambda constexpr

[Mariya Podchishchaeva via Phabricator via cfe-commits]

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Constant evaluator only considered access to `this` pointer to be
possible if `this` poitners was captured. However `this` can also appear if
there was a default member initializer.

Fixes https://github.com/llvm/llvm-project/issues/60936


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D144866

Files:
  clang/lib/AST/ExprConstant.cpp
  clang/test/SemaCXX/lambda-expressions.cpp


Index: clang/test/SemaCXX/lambda-expressions.cpp
===================================================================
--- clang/test/SemaCXX/lambda-expressions.cpp
+++ clang/test/SemaCXX/lambda-expressions.cpp
@@ -665,3 +665,17 @@
                     // expected-note at -2 2 {{default capture by}}
 }
 };
+
+#if __cplusplus > 201402L
+namespace GH60936 {
+struct S {
+    int i;
+    int *p = &i;
+};
+
+static_assert([]() constexpr {
+  S r = S{2};
+  return r.p != nullptr;
+}());
+} // namespace GH60936
+#endif
Index: clang/lib/AST/ExprConstant.cpp
===================================================================
--- clang/lib/AST/ExprConstant.cpp
+++ clang/lib/AST/ExprConstant.cpp
@@ -8758,16 +8758,19 @@
       return false;
     }
     Result = *Info.CurrentCall->This;
-    // If we are inside a lambda's call operator, the 'this' expression refers
-    // to the enclosing '*this' object (either by value or reference) which is
-    // either copied into the closure object's field that represents the '*this'
-    // or refers to '*this'.
+
     if (isLambdaCallOperator(Info.CurrentCall->Callee)) {
-      // Ensure we actually have captured 'this'. (an error will have
-      // been previously reported if not).
+      // Ensure we actually have captured 'this'. If something was wrong with
+      // 'this' capture, the error would have been previously reported.
+      // Otherwise we can be inside of a default initialization of an object
+      // declared by lambda's body, so no need to return false.
       if (!Info.CurrentCall->LambdaThisCaptureField)
-        return false;
+        return true;
 
+      // If we have captured 'this',  the 'this' expression refers
+      // to the enclosing '*this' object (either by value or reference) which is
+      // either copied into the closure object's field that represents the
+      // '*this' or refers to '*this'.
       // Update 'Result' to refer to the data member/field of the closure object
       // that represents the '*this' capture.
       if (!HandleLValueMember(Info, E, Result,


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