From 7ad4fb0e689c5d111aa44e3e3e1ffd2b35e436bb Mon Sep 17 00:00:00 2001
From: Richard Feldman <oss@rtfeldman.com>
Date: Sun, 5 Apr 2020 22:42:24 -0400
Subject: [PATCH] Add List.concat

---
 compiler/builtins/src/std.rs  | 9 +++++++++
 compiler/module/src/symbol.rs | 1 +
 2 files changed, 10 insertions(+)

diff --git a/compiler/builtins/src/std.rs b/compiler/builtins/src/std.rs
index 29ee1285b3..7296872b3e 100644
--- a/compiler/builtins/src/std.rs
+++ b/compiler/builtins/src/std.rs
@@ -408,6 +408,15 @@ pub fn types() -> MutMap<Symbol, (SolvedType, Region)> {
         ),
     );
 
+    // concat : List elem, List elem -> List elem
+    add_type(
+        Symbol::LIST_CONCAT,
+        SolvedType::Func(
+            vec![list_type(flex(TVAR1)), list_type(flex(TVAR1))],
+            Box::new(list_type(flex(TVAR1))),
+        ),
+    );
+
     // map : List before, (before -> after) -> List after
     add_type(
         Symbol::LIST_MAP,
diff --git a/compiler/module/src/symbol.rs b/compiler/module/src/symbol.rs
index 2c28b48df3..1d593916c1 100644
--- a/compiler/module/src/symbol.rs
+++ b/compiler/module/src/symbol.rs
@@ -640,6 +640,7 @@ define_builtins! {
         9 LIST_FOLDL: "foldl"
         10 LIST_FOLDR: "foldr"
         11 LIST_GET_UNSAFE: "getUnsafe" // TODO remove once we can code gen Result
+        12 LIST_CONCAT: "concat"
     }
     7 RESULT: "Result" => {
         0 RESULT_RESULT: "Result" imported // the Result.Result type alias