[clang] [clang] Fix a crash from nested ArrayInitLoopExpr (PR #67722)

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https://github.com/isuckatcs updated 
https://github.com/llvm/llvm-project/pull/67722

>From fb0bf2fcc9d873ce9cf4269cfb6de8786ac6f343 Mon Sep 17 00:00:00 2001
From: isuckatcs <65320245+isucka...@users.noreply.github.com>
Date: Thu, 28 Sep 2023 20:43:23 +0200
Subject: [PATCH 1/2] [clang] Fix a crash from nested ArrayInitLoopExpr

When visiting an ArrayInitLoopExpr, clang creates a temporary
variable for the source array, however in a nested AILE this
variable is created multiple times, in every iteration as they
have the same AST node and clang is unable to differentiate them.

Fixes #57135
---
 clang/lib/AST/ExprConstant.cpp                      | 11 ++++++-----
 .../nested-array-init-loop-in-lambda-capture.cpp    | 13 +++++++++++++
 2 files changed, 19 insertions(+), 5 deletions(-)
 create mode 100644 clang/test/AST/nested-array-init-loop-in-lambda-capture.cpp

diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index fea06b97259fe31..a1f5c262ca10be3 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -10967,19 +10967,20 @@ bool ArrayExprEvaluator::VisitArrayInitLoopExpr(const 
ArrayInitLoopExpr *E) {
   LValue Subobject = This;
   Subobject.addArray(Info, E, CAT);
 
-  bool Success = true;
   for (EvalInfo::ArrayInitLoopIndex Index(Info); Index != Elements; ++Index) {
     if (!EvaluateInPlace(Result.getArrayInitializedElt(Index),
                          Info, Subobject, E->getSubExpr()) ||
         !HandleLValueArrayAdjustment(Info, E, Subobject,
                                      CAT->getElementType(), 1)) {
-      if (!Info.noteFailure())
-        return false;
-      Success = false;
+
+      // There's no need to try and evaluate the rest, as those are the exact
+      // same expressions.
+      std::ignore = Info.noteFailure();
+      return false;
     }
   }
 
-  return Success;
+  return true;
 }
 
 bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E) {
diff --git a/clang/test/AST/nested-array-init-loop-in-lambda-capture.cpp 
b/clang/test/AST/nested-array-init-loop-in-lambda-capture.cpp
new file mode 100644
index 000000000000000..82d27380b637d03
--- /dev/null
+++ b/clang/test/AST/nested-array-init-loop-in-lambda-capture.cpp
@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -std=c++17 -verify 
%s
+// RUN: %clang_cc1 -std=c++17 -verify=ref %s
+
+// ref-no-diagnostics
+// expected-no-diagnostics
+
+void used_to_crash() {
+  int s[2][2];
+
+  int arr[4];
+
+  arr[0] = [s] { return s[0][0]; }();
+}

>From 19c09fb7656ba3b2e170802adfd397dd9aa9fec9 Mon Sep 17 00:00:00 2001
From: isuckatcs <65320245+isucka...@users.noreply.github.com>
Date: Thu, 28 Sep 2023 21:26:40 +0200
Subject: [PATCH 2/2] wrapping the temporary into a scope

---
 clang/lib/AST/ExprConstant.cpp | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index a1f5c262ca10be3..12b4d6b22c2c2bc 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -10950,6 +10950,9 @@ bool 
ArrayExprEvaluator::VisitCXXParenListOrInitListExpr(
 }
 
 bool ArrayExprEvaluator::VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E) {
+
+  FullExpressionRAII Scope(Info);
+
   LValue CommonLV;
   if (E->getCommonExpr() &&
       !Evaluate(Info.CurrentCall->createTemporary(
@@ -10967,20 +10970,19 @@ bool ArrayExprEvaluator::VisitArrayInitLoopExpr(const 
ArrayInitLoopExpr *E) {
   LValue Subobject = This;
   Subobject.addArray(Info, E, CAT);
 
+  bool Success = true;
   for (EvalInfo::ArrayInitLoopIndex Index(Info); Index != Elements; ++Index) {
     if (!EvaluateInPlace(Result.getArrayInitializedElt(Index),
                          Info, Subobject, E->getSubExpr()) ||
         !HandleLValueArrayAdjustment(Info, E, Subobject,
                                      CAT->getElementType(), 1)) {
-
-      // There's no need to try and evaluate the rest, as those are the exact
-      // same expressions.
-      std::ignore = Info.noteFailure();
-      return false;
+      if (!Info.noteFailure())
+        return false;
+      Success = false;
     }
   }
 
-  return true;
+  return Success;
 }
 
 bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E) {

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