From 6713eaff4e90f63904e9c3f36889a5204aebd2f7 Mon Sep 17 00:00:00 2001
From: Karl Meakin <karlwfmeakin@gmail.com>
Date: Thu, 19 Jan 2023 08:13:39 +0000
Subject: [PATCH] letrec tests

---
 tests/succeed/letrec/factorial.fathom | 14 ++++++++++++++
 tests/succeed/letrec/factorial.snap   | 14 ++++++++++++++
 tests/succeed/letrec/fibonacci.fathom | 10 ++++++++++
 tests/succeed/letrec/fibonacci.snap   | 11 +++++++++++
 tests/succeed/letrec/parity.fathom    | 16 ++++++++++++++++
 tests/succeed/letrec/parity.snap      | 14 ++++++++++++++
 6 files changed, 79 insertions(+)
 create mode 100644 tests/succeed/letrec/factorial.fathom
 create mode 100644 tests/succeed/letrec/factorial.snap
 create mode 100644 tests/succeed/letrec/fibonacci.fathom
 create mode 100644 tests/succeed/letrec/fibonacci.snap
 create mode 100644 tests/succeed/letrec/parity.fathom
 create mode 100644 tests/succeed/letrec/parity.snap

diff --git a/tests/succeed/letrec/factorial.fathom b/tests/succeed/letrec/factorial.fathom
new file mode 100644
index 000000000..bebafe849
--- /dev/null
+++ b/tests/succeed/letrec/factorial.fathom
@@ -0,0 +1,14 @@
+// FIXME: using (x - 1) causes a crash in distillation (see https://github.com/yeslogic/fathom/issues/485)
+
+letrec
+    factorial : U32 -> U32
+    = fun (x : U32) => match x {
+        0 => 1,
+        _ => x * factorial (u32_sub x 1),
+    },
+    factorial_iter : U32 -> U32 -> U32
+    = fun (acc: U32) (x : U32) => match x {
+        0 => acc,
+        _ => factorial_iter (acc * x) (u32_sub x 1),
+    };
+(factorial, factorial_iter)
diff --git a/tests/succeed/letrec/factorial.snap b/tests/succeed/letrec/factorial.snap
new file mode 100644
index 000000000..0ef71fe95
--- /dev/null
+++ b/tests/succeed/letrec/factorial.snap
@@ -0,0 +1,14 @@
+stdout = '''
+letrec 
+    factorial : U32 -> U32 = fun x => match x {
+        0 => 1,
+        _ => x * factorial (x - (1 : U32)),
+    },
+    factorial_iter : U32 -> U32 -> U32 = fun acc x => match x {
+        0 => acc,
+        _ => factorial_iter (acc * x) (x - (1 : U32)),
+    },
+;
+(factorial, factorial_iter) : (U32 -> U32, U32 -> U32 -> U32)
+'''
+stderr = ''
diff --git a/tests/succeed/letrec/fibonacci.fathom b/tests/succeed/letrec/fibonacci.fathom
new file mode 100644
index 000000000..5eb00ea3b
--- /dev/null
+++ b/tests/succeed/letrec/fibonacci.fathom
@@ -0,0 +1,10 @@
+// FIXME: using (x - 1) or (x - 2) causes a crash in distillation (see https://github.com/yeslogic/fathom/issues/485)
+
+letrec
+    fibonacci : U32 -> U32
+    = fun (x : U32) => match x {
+        0 => 0,
+        1 => 1,
+        _ => (fibonacci (u32_sub x 1)) + (fibonacci (u32_sub x 2)),
+    };
+fibonacci
diff --git a/tests/succeed/letrec/fibonacci.snap b/tests/succeed/letrec/fibonacci.snap
new file mode 100644
index 000000000..6690c6f87
--- /dev/null
+++ b/tests/succeed/letrec/fibonacci.snap
@@ -0,0 +1,11 @@
+stdout = '''
+letrec 
+    fibonacci : U32 -> U32 = fun x => match x {
+        0 => 0,
+        1 => 1,
+        _ => fibonacci (x - (1 : U32)) + fibonacci (x - (2 : U32)),
+    },
+;
+fibonacci : U32 -> U32
+'''
+stderr = ''
diff --git a/tests/succeed/letrec/parity.fathom b/tests/succeed/letrec/parity.fathom
new file mode 100644
index 000000000..266947892
--- /dev/null
+++ b/tests/succeed/letrec/parity.fathom
@@ -0,0 +1,16 @@
+// FIXME: using (x - 1) causes a crash in distillation (see https://github.com/yeslogic/fathom/issues/485)
+
+letrec
+    is_even : U32 -> Bool
+    = fun (x : U32) => match x {
+        0 => true,
+        _ => is_odd (u32_sub x 1),
+    },
+
+    is_odd : U32 -> Bool
+    = fun (x : U32) => match x {
+        0 => false,
+        _ => is_even (u32_sub x 1),
+    },
+;
+(is_even, is_odd)
diff --git a/tests/succeed/letrec/parity.snap b/tests/succeed/letrec/parity.snap
new file mode 100644
index 000000000..edcb12866
--- /dev/null
+++ b/tests/succeed/letrec/parity.snap
@@ -0,0 +1,14 @@
+stdout = '''
+letrec 
+    is_even : U32 -> Bool = fun x => match x {
+        0 => true,
+        _ => is_odd (x - (1 : U32)),
+    },
+    is_odd : U32 -> Bool = fun x => match x {
+        0 => false,
+        _ => is_even (x - (1 : U32)),
+    },
+;
+(is_even, is_odd) : (U32 -> Bool, U32 -> Bool)
+'''
+stderr = ''