Merge pull request #5167 from roc-lang/fix-closure-captures-recursive

Ensure that closures inside recursive closures capture correctly

crates/compiler/test_mono/generated/recursive_closure_with_transiently_used_capture.txt

@@ -0,0 +1,18 @@
+procedure Test.1 (Test.2, Test.3):
+    let Test.14 : [] = CallByName Test.6 Test.2 Test.3;
+    ret Test.14;
+
+procedure Test.5 (Test.8, Test.4):
+    let Test.12 : [] = CallByName Test.1 Test.4 Test.4;
+    ret Test.12;
+
+procedure Test.6 (Test.15, Test.4):
+    let Test.18 : {} = Struct {};
+    let Test.17 : [] = CallByName Test.5 Test.18 Test.4;
+    ret Test.17;
+
+procedure Test.0 (Test.7):
+    let Test.4 : U16 = 10i64;
+    let Test.10 : {} = Struct {};
+    let Test.9 : [] = CallByName Test.5 Test.10 Test.4;
+    ret Test.9;

crates/compiler/test_mono/src/tests.rs

@@ -2769,3 +2769,23 @@ fn inline_return_joinpoints_in_union_lambda_set() {
         "#
     )
 }
+
+#[mono_test]
+fn recursive_closure_with_transiently_used_capture() {
+    indoc!(
+        r#"
+        app "test" provides [f] to "./platform"
+
+        thenDo = \x, callback ->
+            callback x
+
+        f = \{} ->
+            code = 10u16
+
+            bf = \{} ->
+                thenDo code \_ -> bf {}
+
+            bf {}
+        "#
+    )
+}