fix(es/typescript): Strip declaration of exported function overloads (#9397)

- Closes https://github.com/swc-project/swc/issues/9396

.changeset/eleven-dryers-brake.md

@@ -0,0 +1,6 @@
+---
+swc_fast_ts_strip: patch
+swc_core: patch
+---
+
+fix(es/typescript): Strip declaration of exported function overloads

crates/swc_fast_ts_strip/src/lib.rs

@@ -655,14 +655,6 @@ impl Visit for TsStrip {
         n.visit_children_with(self);
     }
 
-    fn visit_fn_decl(&mut self, n: &FnDecl) {
-        if n.function.body.is_none() {
-            self.add_replacement(n.function.span);
-            return;
-        }
-        n.visit_children_with(self);
-    }
-
     fn visit_import_decl(&mut self, n: &ImportDecl) {
         if n.type_only {
             self.add_replacement(n.span);
@@ -955,6 +947,9 @@ impl IsTsDecl for Decl {
             Self::Var(ref var) => var.declare,
             Self::Fn(FnDecl { declare: true, .. })
             | Self::Class(ClassDecl { declare: true, .. }) => true,
+
+            Self::Fn(FnDecl { function, .. }) => function.body.is_none(),
+
             _ => false,
         }
     }

crates/swc_fast_ts_strip/tests/fixture/issue-9396.js

@@ -0,0 +1 @@
+                    

crates/swc_fast_ts_strip/tests/fixture/issue-9396.transform.js

@@ -0,0 +1 @@
+export { };

crates/swc_fast_ts_strip/tests/fixture/issue-9396.ts

@@ -0,0 +1 @@
+export function f();