Fix eval-ing functions in repl

crates/repl_cli/src/cli_gen.rs

@@ -58,15 +58,7 @@ pub fn gen_and_eval_llvm<'a>(
 
     let (_, main_fn_layout) = match loaded.procedures.keys().find(|(s, _)| *s == main_fn_symbol) {
         Some(layout) => *layout,
-        None => {
-            return (
-                Some(ReplOutput {
-                    expr: "<function>".to_string(),
-                    expr_type: expr_type_str,
-                }),
-                problems,
-            );
-        }
+        None => unreachable!(),
     };
 
     let interns = loaded.interns.clone();
@@ -87,8 +79,15 @@ pub fn gen_and_eval_llvm<'a>(
         layout_interner.into_global().fork(),
         target_info,
     );
+    let expr_str = format_answer(&arena, expr).to_string();
 
-    (Some(format_answer(&arena, expr, expr_type_str)), problems)
+    (
+        Some(ReplOutput {
+            expr: expr_str,
+            expr_type: expr_type_str,
+        }),
+        problems,
+    )
 }
 
 struct CliApp {

crates/repl_eval/src/eval.rs

@@ -13,7 +13,7 @@ use roc_mono::layout::{
     self, union_sorted_tags_pub, Builtin, Layout, LayoutCache, LayoutInterner, UnionLayout,
     UnionVariant, WrappedVariant,
 };
-use roc_parse::ast::{AssignedField, Collection, Expr, StrLiteral};
+use roc_parse::ast::{AssignedField, Collection, Expr, Pattern, StrLiteral};
 use roc_region::all::{Loc, Region};
 use roc_std::RocDec;
 use roc_target::TargetInfo;
@@ -67,7 +67,20 @@ pub fn jit_to_ast<'a, A: ReplApp<'a>>(
             // it's `main` and can be executed.
             jit_to_ast_help(&mut env, app, main_fn_name, &result, var)
         }
-        _ => Expr::MalformedClosure,
+        ProcLayout { arguments, .. } => {
+            // This is a user-supplied function; create a fake Expr for it.
+            let mut arg_patterns =
+                bumpalo::collections::Vec::with_capacity_in(arguments.len(), arena);
+
+            // Put in an underscore for each of the args, just to get the arity right.
+            for _ in 0..arguments.len() {
+                arg_patterns.push(Loc::at_zero(Pattern::Underscore("_")));
+            }
+
+            let body_expr = Loc::at_zero(Expr::Record(Collection::empty()));
+
+            Expr::Closure(arg_patterns.into_bump_slice(), arena.alloc(body_expr))
+        }
     }
 }
 

crates/repl_eval/src/gen.rs

@@ -11,23 +11,26 @@ use roc_region::all::LineInfo;
 use roc_reporting::report::{can_problem, type_problem, RocDocAllocator};
 use roc_target::TargetInfo;
 
+#[derive(Debug)]
 pub struct ReplOutput {
     pub expr: String,
     pub expr_type: String,
 }
 
-pub fn format_answer(arena: &Bump, answer: Expr<'_>, expr_type: String) -> ReplOutput {
-    let mut expr = roc_fmt::Buf::new_in(arena);
+pub fn format_answer<'a>(arena: &'a Bump, answer: Expr<'_>) -> &'a str {
+    match answer {
+        Expr::Closure(_, _) | Expr::MalformedClosure => "<function>",
+        _ => {
+            let mut expr = roc_fmt::Buf::new_in(arena);
 
-    answer.format_with_options(&mut expr, Parens::NotNeeded, Newlines::Yes, 0);
+            answer.format_with_options(&mut expr, Parens::NotNeeded, Newlines::Yes, 0);
 
-    ReplOutput {
-        expr: expr.into_bump_str().to_string(),
-        expr_type,
+            expr.into_bump_str()
+        }
     }
 }
 
-#[derive(Default)]
+#[derive(Default, Debug)]
 pub struct Problems {
     pub errors: Vec<String>,
     pub warnings: Vec<String>,