fix(mangler): no shorthand BindingProperty; handle var hoisting and…

… export variables

crates/oxc_codegen/src/gen.rs

@@ -949,7 +949,7 @@ impl<'a, const MINIFY: bool> Gen<MINIFY> for ModuleExportName<'a> {
     fn gen(&self, p: &mut Codegen<{ MINIFY }>, ctx: Context) {
         match self {
             Self::IdentifierName(identifier) => p.print_str(identifier.name.as_str()),
-            Self::IdentifierReference(identifier) => p.print_str(identifier.name.as_str()),
+            Self::IdentifierReference(identifier) => identifier.gen(p, ctx),
             Self::StringLiteral(literal) => literal.gen(p, ctx),
         };
     }
@@ -2538,22 +2538,19 @@ impl<'a, const MINIFY: bool> Gen<MINIFY> for ObjectPattern<'a> {
     }
 }
 
+// NOTE: `shorthand` is not printed
 impl<'a, const MINIFY: bool> Gen<MINIFY> for BindingProperty<'a> {
     fn gen(&self, p: &mut Codegen<{ MINIFY }>, ctx: Context) {
         p.add_source_mapping(self.span.start);
         if self.computed {
             p.print_char(b'[');
         }
-        if !self.shorthand {
-            self.key.gen(p, ctx);
-        }
+        self.key.gen(p, ctx);
         if self.computed {
             p.print_char(b']');
         }
-        if !self.shorthand {
-            p.print_colon();
-            p.print_soft_space();
-        }
+        p.print_colon();
+        p.print_soft_space();
         self.value.gen(p, ctx);
     }
 }
@@ -2959,8 +2956,8 @@ impl<'a, const MINIFY: bool> Gen<MINIFY> for TSTypeLiteral<'a> {
 impl<'a, const MINIFY: bool> Gen<MINIFY> for TSTypeName<'a> {
     fn gen(&self, p: &mut Codegen<{ MINIFY }>, ctx: Context) {
         match self {
-            Self::IdentifierReference(decl) => {
-                p.print_str(decl.name.as_str());
+            Self::IdentifierReference(ident) => {
+                ident.gen(p, ctx);
             }
             Self::QualifiedName(decl) => {
                 decl.left.gen(p, ctx);

crates/oxc_isolated_declarations/tests/snapshots/function-parameters.snap

@@ -7,8 +7,8 @@ input_file: crates/oxc_isolated_declarations/tests/fixtures/function-parameters.
 export declare function fnDeclGood(p?: T, rParam?: string): void;
 export declare function fnDeclGood2(p?: T, rParam?: number): void;
 export declare function fooGood([a, b]?: any[]): number;
-export declare const fooGood2: ({ a, b }?: object) => number;
-export declare function fooGood3({ a, b: [{ c }] }: object): void;
+export declare const fooGood2: ({ a: a, b: b }?: object) => number;
+export declare function fooGood3({ a: a, b: [{ c: c }] }: object): void;
 export declare function fnDeclBad<T>(p: T, rParam: T, r2: T): void;
 export declare function fnDeclBad2<T>(p: T, r2: T): void;
 export declare function fnDeclBad3<T>(p: T, rParam?: T, r2: T): void;

crates/oxc_mangler/examples/mangler.rs

@@ -27,8 +27,9 @@ fn main() -> std::io::Result<()> {
     println!("{printed}");
 
     if twice {
-        let printed = mangler(&printed, source_type, debug);
-        println!("{printed}");
+        let printed2 = mangler(&printed, source_type, debug);
+        println!("{printed2}");
+        println!("same = {}", printed == printed2);
     }
 
     Ok(())

crates/oxc_mangler/src/lib.rs

@@ -77,8 +77,7 @@ impl ManglerBuilder {
 
     #[must_use]
     pub fn build<'a>(self, program: &'a Program<'a>) -> Mangler {
-        let semantic_ret = SemanticBuilder::new("", program.source_type).build(program);
-        let semantic = semantic_ret.semantic;
+        let semantic = SemanticBuilder::new("", program.source_type).build(program).semantic;
 
         // Mangle the symbol table by computing slots from the scope tree.
         // A slot is the occurrence index of a binding identifier inside a scope.
@@ -101,10 +100,21 @@ impl ManglerBuilder {
                 .get_parent_id(scope_id)
                 .map_or(0, |parent_scope_id| max_slot_for_scope[parent_scope_id.index()]);
 
+            let parent_bindings = scope_tree
+                .get_parent_id(scope_id)
+                .map(|parent_scope_id| scope_tree.get_bindings(parent_scope_id));
+
             let mut slot = parent_max_slot;
 
             // `bindings` are stored in order, traverse and increment slot
             for symbol_id in bindings.values() {
+                // omit var hoisting because var symbols are added to every parent scope
+                if let Some(parent_bindings) = &parent_bindings {
+                    if parent_bindings.values().contains(symbol_id) {
+                        continue;
+                    }
+                }
+
                 slots[*symbol_id] = slot;
                 slot += 1;
             }
@@ -119,12 +129,8 @@ impl ManglerBuilder {
         let frequencies =
             Self::tally_slot_frequencies(&symbol_table, total_number_of_slots, &slots);
 
-        let unresolved_references = scope_tree
-            .root_unresolved_references()
-            .keys()
-            // It is unlike to get a 5 letter mangled identifier, which is a lot of slots.
-            // .filter(|name| name.len() < 5)
-            .collect::<Vec<_>>();
+        let unresolved_references =
+            scope_tree.root_unresolved_references().keys().collect::<Vec<_>>();
 
         let mut names = Vec::with_capacity(total_number_of_slots);
 
@@ -195,7 +201,9 @@ impl ManglerBuilder {
     ) -> Vec<SlotFrequency> {
         let mut frequencies = vec![SlotFrequency::default(); total_number_of_slots];
         for (symbol_id, slot) in slots.iter_enumerated() {
-            if !symbol_table.get_flag(symbol_id).is_variable() {
+            let symbol_flag = symbol_table.get_flag(symbol_id);
+            // omit renaming `export { x }`
+            if !symbol_flag.is_variable() || symbol_flag.is_export() {
                 continue;
             }
             let index = *slot;