Reduce size of AssignmentTargetMaybeDefault

crates/oxc_ast/src/ast/js.rs

@@ -1013,6 +1013,11 @@ pub struct AssignmentExpression<'a> {
 #[cfg_attr(feature = "wasm", derive(Tsify))]
 #[serde(untagged)]
 pub enum AssignmentTarget<'a> {
+    // First discriminant 1, to allow discriminant for `AssignmentTargetMaybeDefault`'s other variant
+    // to fit in the niche before this, so `AssignmentTargetMaybeDefault` can be 24 bytes, not 32
+    #[cfg(feature = "raw")]
+    SimpleAssignmentTarget(SimpleAssignmentTarget<'a>) = 1,
+    #[cfg(not(feature = "raw"))]
     SimpleAssignmentTarget(SimpleAssignmentTarget<'a>),
     AssignmentTargetPattern(AssignmentTargetPattern<'a>),
 }
@@ -1136,13 +1141,16 @@ pub struct AssignmentTargetRest<'a> {
     pub target: AssignmentTarget<'a>,
 }
 
-#[ast_node]
+// No `#[ast_node]` because don't want this type to be `repr(u8)` so that discriminants of `AssignmentTarget`
+// can be folded into this, so this type is 24 bytes, not 32
 #[derive(Debug, Hash, SerAttrs)]
 #[cfg_attr(feature = "serde", derive(Serialize))]
 #[cfg_attr(feature = "wasm", derive(Tsify))]
+#[cfg_attr(feature = "raw", derive(Inspect))]
 #[serde(untagged)]
 pub enum AssignmentTargetMaybeDefault<'a> {
     AssignmentTarget(AssignmentTarget<'a>),
+    // Compiler assigns this discrimant 0
     AssignmentTargetWithDefault(Box<'a, AssignmentTargetWithDefault<'a>>),
 }
 

crates/oxc_ast/src/lib.rs

@@ -68,7 +68,6 @@ fn size_asserts() {
     assert_eq_size!(ast::ClassElement, [u8; 16]);
     assert_eq_size!(ast::ExportDefaultDeclarationKind, [u8; 16]);
     assert_eq_size!(ast::AssignmentTargetPattern, [u8; 16]);
-    #[cfg(not(feature = "raw"))]
     assert_eq_size!(ast::AssignmentTargetMaybeDefault, [u8; 24]);
     assert_eq_size!(ast::AssignmentTargetProperty, [u8; 16]);
     assert_eq_size!(ast::TSLiteral, [u8; 16]);

napi/parser/generate/index.js

@@ -78,6 +78,10 @@ typesByName.Declaration.niche = {offset: 0, size: 1, value: 255};
 flattenEnumVariants('ExportDefaultDeclarationKind', 'Expression', 'Expression');
 typesByName.Expression.niche = {offset: 0, size: 1, value: 255};
 
+typesByName.AssignmentTargetMaybeDefault.variants[1].discriminant = 0;
+flattenEnumVariants('AssignmentTargetMaybeDefault', 'AssignmentTarget', 'AssignmentTarget');
+typesByName.AssignmentTargetMaybeDefault.niche = {offset: 0, size: 1, value: 255};
+
 // Link up types.
 // Delete skipped fields from structs.
 const structs = [];