Fix lambda body parsing (#707)

CHANGELOG.md

@@ -18,6 +18,7 @@ and this project does not currently adhere to a particular versioning scheme.
 - Fix imported constructors not being updated to Constructor expression. ([#674][gh-674])
 - Fix parse error on parenthesized eraser. ([#675][gh-675])
 - Fix IO/FS/read_line when the line ends with a EOF. ([#638][gh-638])
+- Fix lambda body being parsed as tuple in imp syntax. ([#706][gh-706])
 
 ### Added
 
@@ -419,6 +420,7 @@ and this project does not currently adhere to a particular versioning scheme.
 [gh-621]: https://github.com/HigherOrderCO/Bend/issues/621
 [gh-623]: https://github.com/HigherOrderCO/Bend/issues/623
 [gh-629]: https://github.com/HigherOrderCO/Bend/issues/629
+[gh-638]: https://github.com/HigherOrderCO/Bend/issues/638
 [gh-642]: https://github.com/HigherOrderCO/Bend/issues/642
 [gh-643]: https://github.com/HigherOrderCO/Bend/issues/643
 [gh-648]: https://github.com/HigherOrderCO/Bend/issues/648
@@ -427,5 +429,5 @@ and this project does not currently adhere to a particular versioning scheme.
 [gh-673]: https://github.com/HigherOrderCO/Bend/pull/673
 [gh-674]: https://github.com/HigherOrderCO/Bend/issues/674
 [gh-675]: https://github.com/HigherOrderCO/Bend/issues/675
-[gh-638]: https://github.com/HigherOrderCO/Bend/issues/638
+[gh-706]: https://github.com/HigherOrderCO/Bend/issues/706
 [Unreleased]: https://github.com/HigherOrderCO/Bend/compare/0.2.36...HEAD

src/imp/parser.rs

@@ -95,7 +95,7 @@ impl<'a> PyParser<'a> {
         }
       }
       let names = self.list_like(|p| parse_lam_var(p), "", ":", ",", false, 1)?;
-      let bod = self.parse_expr(inline, true)?;
+      let bod = self.parse_expr(inline, false)?;
       Ok(Expr::Lam { names, bod: Box::new(bod) })
     } else if self.starts_with("(") {
       self.advance_one();

tests/golden_tests/run_file/filter_bool_id.bend

@@ -0,0 +1,17 @@
+type Bool:
+  T
+  F
+
+def filter(f, ls):
+  match ls:
+    case List/Nil:
+      return List/Nil
+    case List/Cons:
+      match f(ls.head):
+        case Bool/T:
+          return List/Cons(ls.head, filter(f, ls.tail))
+        case Bool/F:
+          return filter(f, ls.tail)
+
+def main:
+  return filter(lambda x: x, [Bool/T])

tests/snapshots/run_file__filter_bool_id.bend.snap

@@ -0,0 +1,9 @@
+---
+source: tests/golden_tests.rs
+input_file: tests/golden_tests/run_file/filter_bool_id.bend
+---
+NumScott:
+[Bool/T]
+
+Scott:
+[Bool/T]