From 03cda7bbb5dccd6d6be4bc9c5d11fcaef5031e18 Mon Sep 17 00:00:00 2001
From: Alasdair
Date: Tue, 5 Nov 2019 20:03:28 +0000
Subject: Forbid types declared after a scattered union being used in clauses

The following is therefore always forbidden

```
scattered union U

enum E = A | B | C

union clause U = Ctor : E
```

We attempt to detect when this occurs and include a hint indicating the
likely reason why a 'Undefined type E' error might occur in this
circumstance
---
 test/typecheck/fail/scattered_union_rec.expect | 16 ++++++++++++++++
 test/typecheck/fail/scattered_union_rec.sail   |  6 ++++++
 2 files changed, 22 insertions(+)
 create mode 100644 test/typecheck/fail/scattered_union_rec.expect
 create mode 100644 test/typecheck/fail/scattered_union_rec.sail

(limited to 'test/typecheck')

diff --git a/test/typecheck/fail/scattered_union_rec.expect b/test/typecheck/fail/scattered_union_rec.expect
new file mode 100644
index 00000000..cbc9f70a
--- /dev/null
+++ b/test/typecheck/fail/scattered_union_rec.expect
@@ -0,0 +1,16 @@
+Type error:
+[scattered_union_rec.sail]:6:24-25
+6 |union clause U = Ctor : E
+  |                        ^
+  | Undefined type E
+  | This error was caused by:
+  | [scattered_union_rec.sail]:6:0-25
+  | 6 |union clause U = Ctor : E
+  |   |^-----------------------^
+  |   | Types are not well-formed within this type definition. Note that recursive types are forbidden.
+  | This error was caused by:
+  | [scattered_union_rec.sail]:6:13-14
+  | 6 |union clause U = Ctor : E
+  |   |             ^
+  |   | As this is a scattered union clause, this could also be caused by using a type defined after the 'scattered union' declaration
+  | 
diff --git a/test/typecheck/fail/scattered_union_rec.sail b/test/typecheck/fail/scattered_union_rec.sail
new file mode 100644
index 00000000..9f005f4e
--- /dev/null
+++ b/test/typecheck/fail/scattered_union_rec.sail
@@ -0,0 +1,6 @@
+
+scattered union U
+
+enum E = A | B | C
+
+union clause U = Ctor : E
-- 
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