fix: A Symbol should only be declared in one chunk (#338)

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### Description

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---

crates/rolldown/src/bundler/stages/bundle_stage.rs

@@ -116,11 +116,13 @@ impl<'a> BundleStage<'a> {
           Module::Normal(module) => {
             for stmt_info in module.stmt_infos.iter() {
               for declared in &stmt_info.declared_symbols {
-                // TODO: pass debug_assert!(self.graph.symbols.get(*declared).chunk_id.is_none());
-                // FIXME: I don't think this is correct, even though the assigned chunk_id is the same as the current chunk_id.
-                // A declared symbol should only be processed once.
+                let symbol = self.link_output.symbols.get_mut(*declared);
                 debug_assert!(
-                  self.link_output.symbols.get(*declared).chunk_id.unwrap_or(chunk_id) == chunk_id
+                  symbol.chunk_id.unwrap_or(chunk_id) == chunk_id,
+                  "Symbol: {:?}, {:?} in {:?} should only be declared in one chunk",
+                  symbol.name,
+                  declared,
+                  module.resource_id,
                 );
 
                 self.link_output.symbols.get_mut(*declared).chunk_id = Some(chunk_id);

crates/rolldown/src/bundler/visitors/scanner.rs

@@ -259,8 +259,6 @@ impl<'ast> Scanner<'ast> {
           }
           oxc::ast::ast::Declaration::FunctionDeclaration(fn_decl) => {
             let id = fn_decl.id.as_ref().unwrap();
-            // FIXME: remove this line after https://github.com/web-infra-dev/oxc/pull/843 being merged.
-            self.add_declared_id(id.expect_symbol_id());
             self.add_local_export(&id.name, id.expect_symbol_id());
           }
           oxc::ast::ast::Declaration::ClassDeclaration(cls_decl) => {