fix: hoist statements. Fixes #418

crates/rolldown/src/bundler/module_loader/normal_module_task.rs

@@ -144,7 +144,7 @@ impl<'task, T: FileSystem + Default + 'static> NormalModuleTask<'task, T> {
 
     let source_type =
       determine_oxc_source_type(self.resolved_path.path.as_path(), self.module_type);
-    let program = OxcCompiler::parse(Arc::clone(source), source_type);
+    let mut program = OxcCompiler::parse(Arc::clone(source), source_type);
 
     let semantic = program.make_semantic(source_type);
     let (mut symbol_table, scope) = semantic.into_symbol_table_and_scope_tree();
@@ -161,6 +161,7 @@ impl<'task, T: FileSystem + Default + 'static> NormalModuleTask<'task, T> {
       &self.resolved_path.path,
     );
     let namespace_symbol = scanner.namespace_symbol;
+    program.hoist_import_export_from_stmts();
     let scan_result = scanner.scan(program.program());
     if !self.ctx.input_options.treeshake {
       // TODO: tree shaking is not supported yet

crates/rolldown/src/bundler/module_loader/runtime_normal_module_task.rs

@@ -92,7 +92,7 @@ impl RuntimeNormalModuleTask {
     source: &Arc<str>,
   ) -> (OxcProgram, AstScope, ScanResult, AstSymbol, SymbolRef) {
     let source_type = SourceType::default();
-    let program = OxcCompiler::parse(Arc::clone(source), source_type);
+    let mut program = OxcCompiler::parse(Arc::clone(source), source_type);
 
     let semantic = program.make_semantic(source_type);
     let (mut symbol_table, scope) = semantic.into_symbol_table_and_scope_tree();
@@ -109,6 +109,7 @@ impl RuntimeNormalModuleTask {
       &facade_path,
     );
     let namespace_symbol = scanner.namespace_symbol;
+    program.hoist_import_export_from_stmts();
     let scan_result = scanner.scan(program.program());
 
     (program, ast_scope, scan_result, symbol_for_module, namespace_symbol)

crates/rolldown/tests/esbuild/default/es6_from_common_js/artifacts.snap

@@ -26,6 +26,6 @@ var require_bar = __commonJS((exports, module) => {
 
 // entry.js
 var import_foo = require_foo();
-console.log((0,import_foo.foo)(), (0,import_bar.bar)());
 var import_bar = require_bar();
+console.log((0,import_foo.foo)(), (0,import_bar.bar)());
 ```

crates/rolldown/tests/esbuild/default/export_forms_common_js/artifacts.snap

@@ -24,13 +24,13 @@ var init_b = __esm(() => {
 function Fn() {
 }
 var init_commonjs = __esm(() => {
+	init_b();
 	var commonjs_default = 123;
 	var v = 234;
 	let l = 234;
 	const c = 234;
 	class Class {
 	}
-	init_b();
 });
 
 // c.js

crates/rolldown/tests/fixtures/reexport_commonjs/artifacts.snap

@@ -24,8 +24,8 @@ const value = 1;
 var import_commonjs$2 = require_commonjs();
 
 // main.js
-console.log(foo_ns, import_commonjs$2.bar, value, foo_ns.foo);
 var import_commonjs = require_commonjs();
+console.log(foo_ns, import_commonjs$2.bar, value, foo_ns.foo);
 
 var bar$1 = import_commonjs.bar;
 export { bar$1 as bar };

crates/rolldown_oxc/src/compiler.rs

@@ -9,7 +9,7 @@ use oxc::{
   span::SourceType,
 };
 
-use crate::Dummy;
+use crate::{Dummy, StatementExt, TakeIn};
 pub struct OxcCompiler;
 
 #[allow(clippy::box_collection, clippy::non_send_fields_in_send_ty, unused)]
@@ -67,6 +67,23 @@ impl OxcProgram {
     let semantic = SemanticBuilder::new(&self.source, ty).build(self.program()).semantic;
     semantic
   }
+
+  // TODO: should move this to `rolldown` crate
+  pub fn hoist_import_export_from_stmts(&mut self) {
+    let (program, allocator) = self.program_mut_and_allocator();
+    let old_body = program.body.take_in(allocator);
+    program.body.reserve_exact(old_body.len());
+    let mut non_hoisted = oxc::allocator::Vec::new_in(allocator);
+
+    old_body.into_iter().for_each(|top_stmt| {
+      if top_stmt.is_module_declaration_with_source() {
+        program.body.push(top_stmt);
+      } else {
+        non_hoisted.push(top_stmt);
+      }
+    });
+    program.body.extend(non_hoisted);
+  }
 }
 
 impl OxcCompiler {

crates/rolldown_oxc/src/ext/mod.rs

@@ -54,6 +54,9 @@ pub trait StatementExt<'me, 'ast> {
 
   fn is_function_declaration(&self) -> bool;
   fn as_function_declaration(&self) -> Option<&ast::Function<'ast>>;
+
+  fn as_module_declaration(&self) -> Option<&ast::ModuleDeclaration<'ast>>;
+  fn is_module_declaration_with_source(&self) -> bool;
 }
 
 impl<'me, 'ast> StatementExt<'me, 'ast> for ast::Statement<'ast> {
@@ -129,6 +132,18 @@ impl<'me, 'ast> StatementExt<'me, 'ast> for ast::Statement<'ast> {
   fn is_function_declaration(&self) -> bool {
     self.as_function_declaration().is_some()
   }
+
+  fn as_module_declaration(&self) -> Option<&ast::ModuleDeclaration<'ast>> {
+    if let ast::Statement::ModuleDeclaration(module_decl) = self {
+      Some(module_decl)
+    } else {
+      None
+    }
+  }
+
+  fn is_module_declaration_with_source(&self) -> bool {
+    matches!(self.as_module_declaration(), Some(decl) if decl.source().is_some())
+  }
 }
 
 pub trait ExpressionExt<'ast> {