From da9d8a6ecfb0428ce3d6575905f96fa1661c9b80 Mon Sep 17 00:00:00 2001
From: Andrew Kelley <andrew@ziglang.org>
Date: Sun, 24 Mar 2019 18:47:36 -0400
Subject: [PATCH] implement peer type resolution for enum literals

See #683
---
 src/ir.cpp                    | 15 +++++++++++++++
 test/stage1/behavior/enum.zig | 10 ++++++++++
 2 files changed, 25 insertions(+)

diff --git a/src/ir.cpp b/src/ir.cpp
index 29b6eef27ab5..58db31566568 100644
--- a/src/ir.cpp
+++ b/src/ir.cpp
@@ -9573,6 +9573,21 @@ static ZigType *ir_resolve_peer_types(IrAnalyze *ira, AstNode *source_node, ZigT
             continue;
         }
 
+        if (prev_type->id == ZigTypeIdEnum && cur_type->id == ZigTypeIdEnumLiteral) {
+            TypeEnumField *field = find_enum_type_field(prev_type, cur_inst->value.data.x_enum_literal);
+            if (field != nullptr) {
+                continue;
+            }
+        }
+
+        if (cur_type->id == ZigTypeIdEnum && prev_type->id == ZigTypeIdEnumLiteral) {
+            TypeEnumField *field = find_enum_type_field(cur_type, prev_inst->value.data.x_enum_literal);
+            if (field != nullptr) {
+                prev_inst = cur_inst;
+                continue;
+            }
+        }
+
         if (prev_type->id == ZigTypeIdPointer && prev_type->data.pointer.ptr_len == PtrLenC &&
             (cur_type->id == ZigTypeIdComptimeInt || cur_type->id == ZigTypeIdInt))
         {
diff --git a/test/stage1/behavior/enum.zig b/test/stage1/behavior/enum.zig
index 2be675ea340a..f584fc265a9e 100644
--- a/test/stage1/behavior/enum.zig
+++ b/test/stage1/behavior/enum.zig
@@ -913,3 +913,13 @@ test "enum literal cast to enum" {
     var color2 = Color.Auto;
     expect(color1 == color2);
 }
+
+test "peer type resolution with enum literal" {
+    const Items = enum {
+        one,
+        two,
+    };
+
+    expect(Items.two == .two);
+    expect(.two == Items.two);
+}