C gen: implement named value types

Fir/Char.fir

@@ -1,4 +1,4 @@
-type Char(
+value type Char(
     _codePoint: U32,
 )
 

Fir/Str.fir

@@ -1,5 +1,5 @@
 # Immutable, UTF-8 encoded strings.
-type Str(
+value type Str(
     # UTF-8 encoding of the string.
     _bytes: Array[U8],
 )

Fir/StrBuf.fir

@@ -1,4 +1,4 @@
-type StrBuf(
+value type StrBuf(
     # UTF-8 encoding of the string.
     _bytes: Vec[U8],
 )

src/lowering.rs

@@ -56,7 +56,10 @@ pub struct LoweredPgm {
 
 #[derive(Debug)]
 pub enum TypeObjs {
-    Product(HeapObjIdx),
+    Product {
+        idx: HeapObjIdx,
+        value: bool,
+    },
     Sum {
         con_indices: Vec<HeapObjIdx>,
         value: bool,
@@ -346,6 +349,7 @@ pub struct SourceConDecl {
     pub idx: HeapObjIdx,
     pub ty_args: Vec<mono::Type>,
     pub fields: Vec<mono::Type>,
+    pub value: bool,
 }
 
 #[derive(Debug, Clone)]
@@ -811,6 +815,7 @@ pub fn lower(mono_pgm: &mut mono::MonoPgm) -> LoweredPgm {
                                 &name,
                                 con_ty_args,
                                 fields,
+                                con_decl.value,
                             ));
                             con_indices.push(idx);
                         }
@@ -835,12 +840,19 @@ pub fn lower(mono_pgm: &mut mono::MonoPgm) -> LoweredPgm {
                             con_id,
                             con_ty_args,
                             fields,
+                            con_decl.value,
                         ));
                         let old = lowered_pgm
                             .type_objs
                             .entry(con_id.clone())
                             .or_default()
-                            .insert(con_ty_args.clone(), TypeObjs::Product(idx));
+                            .insert(
+                                con_ty_args.clone(),
+                                TypeObjs::Product {
+                                    idx,
+                                    value: con_decl.value,
+                                },
+                            );
                         assert!(old.is_none());
                     }
                 },
@@ -858,7 +870,13 @@ pub fn lower(mono_pgm: &mut mono::MonoPgm) -> LoweredPgm {
                             .type_objs
                             .entry(con_id.clone())
                             .or_default()
-                            .insert(con_ty_args.clone(), TypeObjs::Product(idx));
+                            .insert(
+                                con_ty_args.clone(),
+                                TypeObjs::Product {
+                                    idx,
+                                    value: con_decl.value,
+                                },
+                            );
                         assert!(old.is_none());
                     }
 
@@ -1481,6 +1499,7 @@ fn lower_source_con(
     con_id: &SmolStr,
     con_ty_args: &[mono::Type],
     fields: &mono::ConFields,
+    value: bool,
 ) -> HeapObj {
     HeapObj::Source(SourceConDecl {
         name: con_id.clone(),
@@ -1491,6 +1510,7 @@ fn lower_source_con(
             mono::ConFields::Named(fields) => fields.values().cloned().collect(),
             mono::ConFields::Unnamed(fields) => fields.to_vec(),
         },
+        value,
     })
 }
 

src/lowering/printer.rs

@@ -22,6 +22,7 @@ impl LoweredPgm {
                     idx,
                     ty_args,
                     fields,
+                    value: _,
                 }) => {
                     assert_eq!(idx.0 as usize, heap_obj_idx);
                     buf.push_str(name.as_str());