[clang] Don't preserve the typo expr in the recovery expr for invalid VarDecls (#90948)

With the commit d530894, we now
preserve the initializer for invalid decls with the recovery-expr.

However there is a chance that the original init expr is a typo-expr, we
should not preserve it in the final AST, as typo-expr is an internal AST
node. We should use the one after the typo correction.

This is spotted by a clangd hover crash on the testcase.

Author: hokein

clang-tools-extra/clangd/unittests/HoverTests.cpp

@@ -965,6 +965,19 @@ class Foo final {})cpp";
          // Bindings are in theory public members of an anonymous struct.
          HI.AccessSpecifier = "public";
        }},
+      {// Don't crash on invalid decl with invalid init expr.
+       R"cpp(
+          Unknown [[^abc]] = invalid;
+          // error-ok
+          )cpp",
+       [](HoverInfo &HI) {
+         HI.Name = "abc";
+         HI.Kind = index::SymbolKind::Variable;
+         HI.NamespaceScope = "";
+         HI.Definition = "int abc = <recovery - expr>()";
+         HI.Type = "int";
+         HI.AccessSpecifier = "public";
+       }},
       {// Extra info for function call.
        R"cpp(
           void fun(int arg_a, int &arg_b) {};

clang/lib/Sema/SemaDecl.cpp

@@ -13530,9 +13530,12 @@ void Sema::AddInitializerToDecl(Decl *RealDecl, Expr *Init, bool DirectInit) {
   }
 
   if (VDecl->isInvalidDecl()) {
-    CorrectDelayedTyposInExpr(Init, VDecl);
+    ExprResult Res = CorrectDelayedTyposInExpr(Init, VDecl);
+    SmallVector<Expr *> SubExprs;
+    if (Res.isUsable())
+      SubExprs.push_back(Res.get());
     ExprResult Recovery =
-        CreateRecoveryExpr(Init->getBeginLoc(), Init->getEndLoc(), {Init});
+        CreateRecoveryExpr(Init->getBeginLoc(), Init->getEndLoc(), SubExprs);
     if (Expr *E = Recovery.get())
       VDecl->setInit(E);
     return;

clang/test/AST/ast-dump-recovery.cpp

@@ -419,6 +419,11 @@ void InitializerOfInvalidDecl() {
   // CHECK:      VarDecl {{.*}} invalid InvalidDecl
   // CHECK-NEXT: `-RecoveryExpr {{.*}} '<dependent type>' contains-errors
   // CHECK-NEXT:   `-DeclRefExpr {{.*}} 'int' lvalue Var {{.*}} 'ValidDecl'
+
+  Unknown InvalidDeclWithInvalidInit = Invalid;
+  // CHECK:      VarDecl {{.*}} invalid InvalidDeclWithInvalidInit
+  // CHECK-NEXT: `-RecoveryExpr {{.*}} '<dependent type>' contains-errors
+  // CHECK-NOT:    `-TypoExpr
 }
 
 void RecoverToAnInvalidDecl() {