From ba58735dbd0ca9b2fe22663557b062236cd9542b Mon Sep 17 00:00:00 2001
From: Tristan Swadell <tswadell@google.com>
Date: Wed, 24 Jan 2024 16:29:44 -0800
Subject: [PATCH] Revert the AST copy as some users were relying on Check to be
 mutable (#890)

---
 checker/checker.go | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/checker/checker.go b/checker/checker.go
index 8870739e..57fb3ce5 100644
--- a/checker/checker.go
+++ b/checker/checker.go
@@ -48,9 +48,10 @@ type checker struct {
 // registry.
 func Check(parsed *ast.AST, source common.Source, env *Env) (*ast.AST, *common.Errors) {
 	errs := common.NewErrors(source)
-	checked := ast.Copy(parsed)
+	typeMap := make(map[int64]*types.Type)
+	refMap := make(map[int64]*ast.ReferenceInfo)
 	c := checker{
-		AST:                checked,
+		AST:                ast.NewCheckedAST(parsed, typeMap, refMap),
 		ExprFactory:        ast.NewExprFactory(),
 		env:                env,
 		errors:             &typeErrors{errs: errs},