refactor(downgrade): MaybeThunk

fix-ir/src/lib.rs

@@ -2,7 +2,6 @@ use std::hash::Hash;
 use std::ops::Deref;
 
 use bumpalo::Bump;
-use bumpalo::boxed::Box;
 use bumpalo::collections::Vec;
 use fix_builtins::{BUILTINS, BuiltinId};
 use fix_common::StringId;
@@ -11,6 +10,8 @@ use num_enum::TryFromPrimitive as _;
 use rnix::{TextRange, ast};
 use string_interner::DefaultStringInterner;
 
+use crate::downgrade::DowngradeContext;
+
 pub mod downgrade;
 
 pub type HashMap<'ir, K, V> = hashbrown::HashMap<K, V, hashbrown::DefaultHashBuilder, &'ir Bump>;
@@ -62,6 +63,46 @@ impl<'ir> Deref for RawIrRef<'ir> {
     }
 }
 
+#[repr(C)]
+#[derive(Debug, Clone, Copy)]
+pub enum MaybeThunk {
+    Int(i64),
+    Float(f64),
+    Bool(bool),
+    Null,
+    Str(StringId),
+    Path(StringId),
+    Thunk(ThunkId),
+    Arg { layer: usize },
+    Builtin(BuiltinId),
+    Builtins,
+    ReplBinding(StringId),
+    ScopedImportBinding(StringId),
+    WithLookup(StringId),
+}
+
+impl MaybeThunk {
+    fn to_ir<'id, 'ir>(self, ctx: &mut impl DowngradeContext<'id, 'ir>) -> IrRef<'id, 'ir> {
+        use MaybeThunk::*;
+        let ir = match self {
+            Int(x) => Ir::Int(x),
+            Float(x) => Ir::Float(x),
+            Bool(x) => Ir::Bool(x),
+            Null => Ir::Null,
+            Str(x) => Ir::Str(x),
+            Path(x) => Ir::Path(ctx.new_expr(Ir::Str(x))),
+            Thunk(x) => Ir::Thunk(x),
+            Arg { layer } => Ir::Arg { layer },
+            Builtin(x) => Ir::Builtin(x),
+            Builtins => Ir::Builtins,
+            ReplBinding(x) => Ir::ReplBinding(x),
+            ScopedImportBinding(x) => Ir::ScopedImportBinding(x),
+            WithLookup(x) => Ir::WithLookup(x),
+        };
+        ctx.new_expr(ir)
+    }
+}
+
 #[repr(C)]
 #[derive(Debug)]
 pub enum Ir<'ir, Ref> {
@@ -69,15 +110,15 @@ pub enum Ir<'ir, Ref> {
     Float(f64),
     Bool(bool),
     Null,
-    Str(Box<'ir, String>),
+    Str(StringId),
+    Path(Ref),
     AttrSet {
-        stcs: HashMap<'ir, StringId, (Ref, TextRange)>,
-        dyns: Vec<'ir, (Ref, Ref, TextRange)>,
+        stcs: HashMap<'ir, StringId, (MaybeThunk, TextRange)>,
+        dyns: Vec<'ir, (Ref, MaybeThunk, TextRange)>,
     },
     List {
-        items: Vec<'ir, Ref>,
+        items: Vec<'ir, MaybeThunk>,
     },
-    Path(Ref),
     ConcatStrings {
         parts: Vec<'ir, Ref>,
         force_string: bool,
@@ -118,7 +159,7 @@ pub enum Ir<'ir, Ref> {
     },
 
     With {
-        namespace: Ref,
+        namespace: MaybeThunk,
         body: Ref,
         thunks: Vec<'ir, (ThunkId, Ref)>,
     },
@@ -135,7 +176,7 @@ pub enum Ir<'ir, Ref> {
     },
     Call {
         func: Ref,
-        arg: Ref,
+        arg: MaybeThunk,
         span: TextRange,
     },