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

[Nathan Ridge via cfe-commits]

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

Fixes https://github.com/clangd/clangd/issues/1821

>From 42ee794d3de89241fae7314db2202cac32af469b 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 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 9fdd8eb236d1ee..7e13cb6e8fc59c 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -13435,8 +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()) {
-    CorrectDelayedTyposInExpr(Init, dyn_cast_or_null<VarDecl>(RealDecl));
+  if (!RealDecl) {
     return;
   }
 
@@ -13456,6 +13455,14 @@ void Sema::AddInitializerToDecl(Decl *RealDecl, Expr *Init, bool DirectInit) {
     return;
   }
 
+  if (VDecl->isInvalidDecl()) {
+    CorrectDelayedTyposInExpr(Init, VDecl);
+    VDecl->setInit(
+        CreateRecoveryExpr(Init->getBeginLoc(), Init->getEndLoc(), {Init})
+            .get());
+    return;
+  }
+
   // WebAssembly tables can't be used to initialise a variable.
   if (Init && !Init->getType().isNull() &&
       Init->getType()->isWebAssemblyTableType()) {