From 03e83b2323be6897a51e2e085854b584eb1e1c83 Mon Sep 17 00:00:00 2001
From: imteekay <leandrotk100@gmail.com>
Date: Sat, 3 Jun 2023 17:39:19 -0300
Subject: [PATCH] Allow redeclare variables defined with `var`

---
 baselines/reference/redeclare.errors.baseline |  7 +----
 baselines/reference/redeclare.tree.baseline   |  4 +++
 src/bind.ts                                   | 29 ++++++++++++++++---
 3 files changed, 30 insertions(+), 10 deletions(-)

diff --git a/baselines/reference/redeclare.errors.baseline b/baselines/reference/redeclare.errors.baseline
index de1418f..0637a08 100644
--- a/baselines/reference/redeclare.errors.baseline
+++ b/baselines/reference/redeclare.errors.baseline
@@ -1,6 +1 @@
-[
-  {
-    "pos": 14,
-    "message": "Cannot redeclare x; first declared at 3"
-  }
-]
\ No newline at end of file
+[]
\ No newline at end of file
diff --git a/baselines/reference/redeclare.tree.baseline b/baselines/reference/redeclare.tree.baseline
index 6d5f7f3..6b11892 100644
--- a/baselines/reference/redeclare.tree.baseline
+++ b/baselines/reference/redeclare.tree.baseline
@@ -4,6 +4,10 @@
       {
         "kind": "Var",
         "pos": 3
+      },
+      {
+        "kind": "Var",
+        "pos": 14
       }
     ]
   },
diff --git a/src/bind.ts b/src/bind.ts
index dccdb0d..8231d14 100644
--- a/src/bind.ts
+++ b/src/bind.ts
@@ -1,4 +1,4 @@
-import { Module, Node, Statement, Table } from './types';
+import { Declaration, Module, Node, Statement, Table } from './types';
 import { error } from './error';
 
 export function bind(m: Module) {
@@ -16,9 +16,9 @@ export function bind(m: Module) {
       if (symbol) {
         const other = symbol.declarations.find(
           (d) =>
-            d.kind === statement.kind ||
-            (d.kind === Node.Var && statement.kind === Node.Let) ||
-            (d.kind === Node.Let && statement.kind === Node.Var),
+            hasEqualKindButNotVar(d, statement) ||
+            willRedeclareVarWithLet(d, statement) ||
+            willRedeclareLetWithVar(d, statement),
         );
         if (other) {
           error(
@@ -41,6 +41,27 @@ export function bind(m: Module) {
       }
     }
   }
+
+  function hasEqualKindButNotVar(
+    declaration: Declaration,
+    statement: Statement,
+  ) {
+    return declaration.kind === statement.kind && statement.kind !== Node.Var;
+  }
+
+  function willRedeclareVarWithLet(
+    declaration: Declaration,
+    statement: Statement,
+  ) {
+    return declaration.kind === Node.Var && statement.kind === Node.Let;
+  }
+
+  function willRedeclareLetWithVar(
+    declaration: Declaration,
+    statement: Statement,
+  ) {
+    return declaration.kind === Node.Let && statement.kind === Node.Var;
+  }
 }
 
 export function resolve(