From 005427744daa8d70abeffde9a05831b4bdb0682f Mon Sep 17 00:00:00 2001
From: Bruce Hill <bruce@bruce-hill.com>
Date: Tue, 23 Apr 2024 13:04:31 -0400
Subject: Prevent shadowing variables

---
 typecheck.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/typecheck.c b/typecheck.c
index e0235308..229a8cd2 100644
--- a/typecheck.c
+++ b/typecheck.c
@@ -111,9 +111,11 @@ void bind_statement(env_t *env, ast_t *statement)
     }
     case Declare: {
         auto decl = Match(statement, Declare);
+        const char *name = Match(decl->var, Var)->name;
+        if (get_binding(env, name))
+            code_err(decl->var, "A %T called '%s' has already been defined", get_binding(env, name)->type, name);
         bind_statement(env, decl->value);
         type_t *type = get_type(env, decl->value);
-        const char *name = Match(decl->var, Var)->name;
         CORD code = CORD_cat(env->scope_prefix ? env->scope_prefix : "$", name);
         set_binding(env, name, new(binding_t, .type=type, .code=code));
         break;
-- 
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