[clang] [clang][Sema] Preserve the initializer of invalid VarDecls (PR #88645)

[Nathan Ridge via cfe-commits]

https://github.com/HighCommander4 updated https://github.com/llvm/llvm-project/pull/88645

>From 97170ed63643832f305254ba1788b99f90f9330d Mon Sep 17 00:00:00 2001
From: Nathan Ridge <zeratul976 at hotmail.com>
Date: Sun, 14 Apr 2024 02:41:48 -0400
Subject: [PATCH] [clang][Sema] Preserve the initializer of invalid VarDecls

Fixes https://github.com/clangd/clangd/issues/1821
---
 clang/lib/Sema/SemaDecl.cpp          | 11 ++++++++++-
 clang/test/AST/ast-dump-recovery.cpp |  8 ++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 9fdd8eb236d1ee..ffb254efeabda3 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -13435,7 +13435,7 @@ void Sema::checkNonTrivialCUnion(QualType QT, SourceLocation Loc,
 void Sema::AddInitializerToDecl(Decl *RealDecl, Expr *Init, bool DirectInit) {
   // If there is no declaration, there was an error parsing it.  Just ignore
   // the initializer.
-  if (!RealDecl || RealDecl->isInvalidDecl()) {
+  if (!RealDecl) {
     CorrectDelayedTyposInExpr(Init, dyn_cast_or_null<VarDecl>(RealDecl));
     return;
   }
@@ -13456,6 +13456,15 @@ void Sema::AddInitializerToDecl(Decl *RealDecl, Expr *Init, bool DirectInit) {
     return;
   }
 
+  if (VDecl->isInvalidDecl()) {
+    CorrectDelayedTyposInExpr(Init, VDecl);
+    ExprResult Recovery =
+        CreateRecoveryExpr(Init->getBeginLoc(), Init->getEndLoc(), {Init});
+    if (Expr *E = Recovery.get())
+      VDecl->setInit(E);
+    return;
+  }
+
   // WebAssembly tables can't be used to initialise a variable.
   if (Init && !Init->getType().isNull() &&
       Init->getType()->isWebAssemblyTableType()) {
diff --git a/clang/test/AST/ast-dump-recovery.cpp b/clang/test/AST/ast-dump-recovery.cpp
index cfb013585ad744..77527743fe8577 100644
--- a/clang/test/AST/ast-dump-recovery.cpp
+++ b/clang/test/AST/ast-dump-recovery.cpp
@@ -413,6 +413,14 @@ void RecoveryExprForInvalidDecls(Unknown InvalidDecl) {
   // CHECK-NEXT: `-RecoveryExpr {{.*}} '<dependent type>'
 }
 
+void InitializerOfInvalidDecl() {
+  int ValidDecl;
+  Unkown InvalidDecl = ValidDecl;
+  // CHECK:      VarDecl {{.*}} invalid InvalidDecl
+  // CHECK-NEXT: `-RecoveryExpr {{.*}} '<dependent type>' contains-errors
+  // CHECK-NEXT:   `-DeclRefExpr {{.*}} 'int' lvalue Var {{.*}} 'ValidDecl'
+}
+
 void RecoverToAnInvalidDecl() {
   Unknown* foo; // invalid decl
   goo; // the typo was correct to the invalid foo.