---

yaml
---
r: 36665
b: refs/heads/try2
c: 7d556e1
h: refs/heads/master
i:
  36663: b44d7cd
v: v3

Author: brson

[refs]

@@ -5,7 +5,7 @@ refs/heads/snap-stage3: eb8fd119c65c67f3b1b8268cc7341c22d39b7b61
 refs/heads/try: d324a424d8f84b1eb049b12cf34182bda91b0024
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/ndm: f3868061cd7988080c30d6d5bf352a5a5fe2460b
-refs/heads/try2: 6e38e334de13d878da91991c4c5e9014a06f93cb
+refs/heads/try2: 7d556e18b05dbac67d2c5d17c332b5d44afcb192
 refs/heads/incoming: d9317a174e434d4c99fc1a37fd7dc0d2f5328d37
 refs/heads/dist-snap: 22efa39382d41b084fde1719df7ae8ce5697d8c9
 refs/tags/release-0.2: c870d2dffb391e14efb05aa27898f1f6333a9596

branches/try2/src/libsyntax/ext/deriving.rs

@@ -698,26 +698,30 @@ fn expand_deriving_eq_enum_method(cx: ext_ctxt,
         };
         other_arms.push(move matching_arm);
 
-        // Create the nonmatching pattern.
-        let nonmatching_pat = @{
-            id: cx.next_id(),
-            node: pat_wild,
-            span: span
-        };
-
-        // Create the nonmatching pattern body.
-        let nonmatching_expr = build::mk_bool(cx, span, !is_eq);
-        let nonmatching_body_block = build::mk_simple_block(cx,
-                                                            span,
-                                                            nonmatching_expr);
-
-        // Create the nonmatching arm.
-        let nonmatching_arm = {
-            pats: ~[ nonmatching_pat ],
-            guard: None,
-            body: move nonmatching_body_block
-        };
-        other_arms.push(move nonmatching_arm);
+        // Maybe generate a non-matching case. If there is only one
+        // variant then there will always be a match.
+        if enum_definition.variants.len() > 1 {
+            // Create the nonmatching pattern.
+            let nonmatching_pat = @{
+                id: cx.next_id(),
+                node: pat_wild,
+                span: span
+            };
+
+            // Create the nonmatching pattern body.
+            let nonmatching_expr = build::mk_bool(cx, span, !is_eq);
+            let nonmatching_body_block = build::mk_simple_block(cx,
+                                                                span,
+                                                                nonmatching_expr);
+
+            // Create the nonmatching arm.
+            let nonmatching_arm = {
+                pats: ~[ nonmatching_pat ],
+                guard: None,
+                body: move nonmatching_body_block
+            };
+            other_arms.push(move nonmatching_arm);
+        }
 
         // Create the self pattern.
         let self_pat = create_enum_variant_pattern(cx,

branches/try2/src/test/run-pass/deriving-enum-single-variant.rs

@@ -0,0 +1,8 @@
+type task_id = int;
+
+#[deriving_eq]
+pub enum Task {
+    TaskHandle(task_id)
+}
+
+fn main() { }