From 51a27022b9a3fa8767797813b23803ea1ecad3e2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Donny/=EA=B0=95=EB=8F=99=EC=9C=A4?= <kdy1997.dev@gmail.com>
Date: Sat, 22 Jun 2024 08:46:37 +0900
Subject: [PATCH] feat(es/transform): Add experimental `.d.ts` generation
 (#9093)

---
 Cargo.lock                                    |   1 +
 crates/swc/Cargo.toml                         |   1 +
 crates/swc/src/config/mod.rs                  |  10 ++
 crates/swc/src/lib.rs                         |  34 +++-
 .../2020/case1/input/index.swc-stderr         |  11 ++
 .../8935/input/src/button.swc-stderr          |  12 ++
 .../ignore-dynamic/1/input/index.swc-stderr   |  12 ++
 crates/swc/tests/projects.rs                  | 160 +++++++++++-------
 .../ts-isolated-declaration/error/.swcrc      |  10 ++
 .../ts-isolated-declaration/oxc/README.md     |   3 +
 .../ts-isolated-declaration/oxc/input/.swcrc  |  11 ++
 .../oxc/input/arrow-function-return-type.ts   |   9 +
 .../oxc/input/as-const.swc-stderr             |  16 ++
 .../oxc/input/as-const.ts                     |  16 ++
 .../oxc/input/async-function.ts               |  16 ++
 .../oxc/input/eliminate-imports.ts            |   7 +
 .../oxc/input/empty-export.ts                 |   4 +
 .../oxc/input/function-overloads.swc-stderr   |  11 ++
 .../oxc/input/function-overloads.ts           |   7 +
 .../oxc/input/function-parameters.ts          |  24 +++
 .../oxc/input/generator.ts                    |  10 ++
 .../oxc/input/infer-expression.swc-stderr     |  31 ++++
 .../oxc/input/infer-expression.ts             |   5 +
 .../oxc/input/infer-return-type.ts            |  27 +++
 .../input/infer-template-literal.swc-stderr   |  28 +++
 .../oxc/input/infer-template-literal.ts       |  10 ++
 .../non-exported-binding-elements.swc-stderr  |  24 +++
 .../input/non-exported-binding-elements.ts    |  10 ++
 .../oxc/input/readonly.ts                     |   4 +
 .../output/arrow-function-return-type.d.ts    |   3 +
 .../oxc/output/arrow-function-return-type.ts  |   9 +
 .../oxc/output/as-const.d.ts                  |  17 ++
 .../oxc/output/as-const.ts                    |  22 +++
 .../oxc/output/async-function.d.ts            |   4 +
 .../oxc/output/async-function.ts              |  58 +++++++
 .../oxc/output/eliminate-imports.d.ts         |   9 +
 .../oxc/output/eliminate-imports.ts           |  20 +++
 .../oxc/output/empty-export.d.ts              |   2 +
 .../oxc/output/empty-export.ts                |   3 +
 .../oxc/output/function-overloads.d.ts        |   5 +
 .../oxc/output/function-overloads.ts          |   3 +
 .../oxc/output/function-parameters.d.ts       |  15 ++
 .../oxc/output/function-parameters.ts         |  46 +++++
 .../oxc/output/generator.d.ts                 |   2 +
 .../oxc/output/generator.ts                   |  28 +++
 .../oxc/output/infer-expression.d.ts          |   4 +
 .../oxc/output/infer-expression.ts            |   5 +
 .../oxc/output/infer-return-type.d.ts         |   4 +
 .../oxc/output/infer-return-type.ts           |  24 +++
 .../oxc/output/infer-template-literal.d.ts    |   7 +
 .../oxc/output/infer-template-literal.ts      |  11 ++
 .../output/non-exported-binding-elements.d.ts |   5 +
 .../output/non-exported-binding-elements.ts   |  16 ++
 .../oxc/output/readonly.d.ts                  |   4 +
 .../oxc/output/readonly.ts                    |   2 +
 .../ts-isolated-declaration/simple/.swcrc     |  10 ++
 .../ts-isolated-declaration/simple/input/1.ts |   4 +
 .../ts-isolated-declaration/simple/input/2.ts |   1 +
 .../ts-isolated-declaration/simple/input/3.ts |   1 +
 .../simple/output/1.d.ts                      |   1 +
 .../simple/output/1.ts                        |   1 +
 .../simple/output/2.d.ts                      |   1 +
 .../simple/output/2.ts                        |   1 +
 .../simple/output/3.d.ts                      |   4 +
 .../simple/output/3.ts                        |   5 +
 crates/swc_typescript/src/diagnostic.rs       |  14 +-
 crates/swc_typescript/src/fast_dts/mod.rs     |   2 +-
 67 files changed, 825 insertions(+), 72 deletions(-)
 create mode 100644 crates/swc/tests/fixture/issues-2xxx/2020/case1/input/index.swc-stderr
 create mode 100644 crates/swc/tests/fixture/issues-8xxx/8935/input/src/button.swc-stderr
 create mode 100644 crates/swc/tests/fixture/module/ignore-dynamic/1/input/index.swc-stderr
 create mode 100644 crates/swc/tests/ts-isolated-declaration/error/.swcrc
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/README.md
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/input/.swcrc
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/input/arrow-function-return-type.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/input/as-const.swc-stderr
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/input/as-const.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/input/async-function.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/input/eliminate-imports.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/input/empty-export.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/input/function-overloads.swc-stderr
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/input/function-overloads.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/input/function-parameters.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/input/generator.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/input/infer-expression.swc-stderr
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/input/infer-expression.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/input/infer-return-type.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/input/infer-template-literal.swc-stderr
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/input/infer-template-literal.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/input/non-exported-binding-elements.swc-stderr
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/input/non-exported-binding-elements.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/input/readonly.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/output/arrow-function-return-type.d.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/output/arrow-function-return-type.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/output/as-const.d.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/output/as-const.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/output/async-function.d.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/output/async-function.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/output/eliminate-imports.d.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/output/eliminate-imports.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/output/empty-export.d.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/output/empty-export.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/output/function-overloads.d.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/output/function-overloads.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/output/function-parameters.d.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/output/function-parameters.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/output/generator.d.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/output/generator.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/output/infer-expression.d.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/output/infer-expression.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/output/infer-return-type.d.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/output/infer-return-type.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/output/infer-template-literal.d.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/output/infer-template-literal.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/output/non-exported-binding-elements.d.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/output/non-exported-binding-elements.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/output/readonly.d.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/oxc/output/readonly.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/simple/.swcrc
 create mode 100644 crates/swc/tests/ts-isolated-declaration/simple/input/1.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/simple/input/2.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/simple/input/3.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/simple/output/1.d.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/simple/output/1.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/simple/output/2.d.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/simple/output/2.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/simple/output/3.d.ts
 create mode 100644 crates/swc/tests/ts-isolated-declaration/simple/output/3.ts

diff --git a/Cargo.lock b/Cargo.lock
index 62ce8e21205d..613086248ca1 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3744,6 +3744,7 @@ dependencies = [
  "swc_plugin_runner",
  "swc_timer",
  "swc_transform_common",
+ "swc_typescript",
  "swc_visit",
  "testing",
  "tokio",
diff --git a/crates/swc/Cargo.toml b/crates/swc/Cargo.toml
index 9a38ea24db9a..af8daedcc1d6 100644
--- a/crates/swc/Cargo.toml
+++ b/crates/swc/Cargo.toml
@@ -107,6 +107,7 @@ swc_plugin_proxy = { version = "0.44.0", path = "../swc_plugin_proxy", optional
 swc_plugin_runner = { version = "0.109.0", path = "../swc_plugin_runner", optional = true, default-features = false }
 swc_timer = { version = "0.22.0", path = "../swc_timer" }
 swc_transform_common = { version = "0.1.1", path = "../swc_transform_common" }
+swc_typescript = { version = "0.1.1", path = "../swc_typescript" }
 swc_visit = { version = "0.5.14", path = "../swc_visit" }
 
   [dependencies.tokio]
diff --git a/crates/swc/src/config/mod.rs b/crates/swc/src/config/mod.rs
index aaf7cc9a5079..96bb7a2521aa 100644
--- a/crates/swc/src/config/mod.rs
+++ b/crates/swc/src/config/mod.rs
@@ -782,6 +782,7 @@ impl Options {
             emit_assert_for_import_attributes: experimental
                 .emit_assert_for_import_attributes
                 .into_bool(),
+            emit_isolated_dts: experimental.emit_isolated_dts.into_bool(),
         })
     }
 }
@@ -1088,6 +1089,8 @@ pub struct BuiltInput<P: swc_ecma_visit::Fold> {
 
     pub output: JscOutputConfig,
     pub emit_assert_for_import_attributes: bool,
+
+    pub emit_isolated_dts: bool,
 }
 
 impl<P> BuiltInput<P>
@@ -1117,6 +1120,7 @@ where
             emit_source_map_columns: self.emit_source_map_columns,
             output: self.output,
             emit_assert_for_import_attributes: self.emit_assert_for_import_attributes,
+            emit_isolated_dts: self.emit_isolated_dts,
         }
     }
 }
@@ -1211,6 +1215,12 @@ pub struct JscExperimental {
 
     #[serde(default)]
     pub disable_builtin_transforms_for_internal_testing: BoolConfig<false>,
+
+    /// Emit TypeScript definitions for `.ts`, `.tsx` files.
+    ///
+    /// This requires `isolatedDeclartion` feature of TypeScript 5.5.
+    #[serde(default)]
+    pub emit_isolated_dts: BoolConfig<false>,
 }
 
 #[derive(Debug, Clone, Copy, Serialize, Deserialize)]
diff --git a/crates/swc/src/lib.rs b/crates/swc/src/lib.rs
index 576016539cd9..a529608a7544 100644
--- a/crates/swc/src/lib.rs
+++ b/crates/swc/src/lib.rs
@@ -136,7 +136,7 @@ use swc_common::{
 pub use swc_compiler_base::{PrintArgs, TransformOutput};
 pub use swc_config::config_types::{BoolConfig, BoolOr, BoolOrDataConfig};
 use swc_ecma_ast::{EsVersion, Program};
-use swc_ecma_codegen::Node;
+use swc_ecma_codegen::{to_code, Node};
 use swc_ecma_loader::resolvers::{
     lru::CachingResolver, node::NodeModulesResolver, tsc::TsConfigResolver,
 };
@@ -155,6 +155,8 @@ use swc_ecma_visit::{FoldWith, VisitMutWith, VisitWith};
 pub use swc_error_reporters::handler::{try_with_handler, HandlerOpts};
 pub use swc_node_comments::SwcComments;
 use swc_timer::timer;
+use swc_transform_common::output::emit;
+use swc_typescript::fast_dts::FastDts;
 use tracing::warn;
 use url::Url;
 
@@ -731,7 +733,7 @@ impl Compiler {
                 None
             };
 
-            self.apply_transforms(handler, orig, config)
+            self.apply_transforms(handler, fm.clone(), orig, config)
         })
     }
 
@@ -949,11 +951,13 @@ impl Compiler {
     fn apply_transforms(
         &self,
         handler: &Handler,
+        fm: Arc<SourceFile>,
         orig: Option<sourcemap::SourceMap>,
         config: BuiltInput<impl swc_ecma_visit::Fold>,
     ) -> Result<TransformOutput, Error> {
         self.run(|| {
             let program = config.program;
+            let emit_dts = config.syntax.typescript() && config.emit_isolated_dts;
             let source_map_names = if config.source_maps.enabled() {
                 let mut v = swc_compiler_base::IdentCollector {
                     names: Default::default(),
@@ -966,8 +970,34 @@ impl Compiler {
                 Default::default()
             };
 
+            let dts_code = if emit_dts && program.is_module() {
+                let mut checker = FastDts::new(fm.name.clone().into());
+                let mut module = program.clone().expect_module();
+
+                let issues = checker.transform(&mut module);
+
+                for issue in issues {
+                    let range = issue.range();
+
+                    handler
+                        .struct_span_err(range.span, &issue.to_string())
+                        .emit();
+                }
+                let dts_code = to_code(&module);
+                Some(dts_code)
+            } else {
+                None
+            };
+
             let mut pass = config.pass;
             let (program, output) = swc_transform_common::output::capture(|| {
+                if let Some(dts_code) = dts_code {
+                    emit(
+                        "__swc_isolated_declarations__".into(),
+                        serde_json::Value::String(dts_code),
+                    );
+                }
+
                 helpers::HELPERS.set(&Helpers::new(config.external_helpers), || {
                     HANDLER.set(handler, || {
                         // Fold module
diff --git a/crates/swc/tests/fixture/issues-2xxx/2020/case1/input/index.swc-stderr b/crates/swc/tests/fixture/issues-2xxx/2020/case1/input/index.swc-stderr
new file mode 100644
index 000000000000..ca3c223d80b7
--- /dev/null
+++ b/crates/swc/tests/fixture/issues-2xxx/2020/case1/input/index.swc-stderr
@@ -0,0 +1,11 @@
+
+  x cannot reassign to a variable declared with `const`
+   ,-[$DIR/tests/fixture/issues-2xxx/2020/case1/input/index.js:1:1]
+ 1 | const createRegisterItems = (registerType) => async (a, b) => {
+   :                                                      |
+   :                                                      `-- cannot reassign
+ 2 |     const a = root?.test;
+   :           |
+   :           `-- const variable was declared here
+ 3 | };
+   `----
diff --git a/crates/swc/tests/fixture/issues-8xxx/8935/input/src/button.swc-stderr b/crates/swc/tests/fixture/issues-8xxx/8935/input/src/button.swc-stderr
new file mode 100644
index 000000000000..df5e54f0bf35
--- /dev/null
+++ b/crates/swc/tests/fixture/issues-8xxx/8935/input/src/button.swc-stderr
@@ -0,0 +1,12 @@
+
+  x the name `Button` is defined multiple times
+   ,-[$DIR/tests/fixture/issues-8xxx/8935/input/src/button.jsx:1:1]
+ 1 | export function Button(props) {
+   :                 ^^^|^^
+   :                    `-- previous definition of `Button` here
+ 2 |     return <button {...props} />;
+ 3 |   }export function Button(props) {
+   :                    ^^^|^^
+   :                       `-- `Button` redefined here
+ 4 |   return <button {...props} />;
+   `----
diff --git a/crates/swc/tests/fixture/module/ignore-dynamic/1/input/index.swc-stderr b/crates/swc/tests/fixture/module/ignore-dynamic/1/input/index.swc-stderr
new file mode 100644
index 000000000000..829b5970ed3d
--- /dev/null
+++ b/crates/swc/tests/fixture/module/ignore-dynamic/1/input/index.swc-stderr
@@ -0,0 +1,12 @@
+
+  x the name `foo` is defined multiple times
+   ,-[$DIR/tests/fixture/module/ignore-dynamic/1/input/index.js:1:1]
+ 1 | import foo from "foo";
+   :        ^|^
+   :         `-- previous definition of `foo` here
+ 2 | 
+ 3 | async function foo() {
+   :                ^|^
+   :                 `-- `foo` redefined here
+ 4 |     await import("foo");
+   `----
diff --git a/crates/swc/tests/projects.rs b/crates/swc/tests/projects.rs
index 1abe28746d56..3b22c6321b70 100644
--- a/crates/swc/tests/projects.rs
+++ b/crates/swc/tests/projects.rs
@@ -776,83 +776,119 @@ fn should_visit() {
 #[testing::fixture("tests/fixture/**/input/")]
 #[testing::fixture("tests/vercel/**/input/")]
 fn fixture(input_dir: PathBuf) {
-    tests(input_dir)
+    tests(input_dir, Some(IsModule::Unknown));
 }
 
-fn tests(input_dir: PathBuf) {
-    let output = input_dir.parent().unwrap().join("output");
+#[testing::fixture("tests/ts-isolated-declaration/**/input/")]
+fn ts_id(input_dir: PathBuf) {
+    tests(input_dir, Some(IsModule::Bool(true)));
+}
 
-    Tester::new()
-        .print_errors(|cm, handler| {
-            let c = Compiler::new(cm.clone());
+fn tests(input_dir: PathBuf, is_module: Option<IsModule>) {
+    let output_dir = input_dir.parent().unwrap().join("output");
 
-            for entry in WalkDir::new(&input_dir) {
-                let entry = entry.unwrap();
-                if entry.metadata().unwrap().is_dir() {
-                    continue;
-                }
-                println!("File: {}", entry.path().to_string_lossy());
+    for entry in WalkDir::new(&input_dir) {
+        let entry = entry.unwrap();
 
-                if !entry.file_name().to_string_lossy().ends_with(".ts")
-                    && !entry.file_name().to_string_lossy().ends_with(".js")
-                    && !entry.file_name().to_string_lossy().ends_with(".jsx")
-                    && !entry.file_name().to_string_lossy().ends_with(".tsx")
-                {
-                    continue;
-                }
+        let errors = Tester::new().print_errors(|cm, handler| {
+            let c = Compiler::new(cm.clone());
 
-                let rel_path = entry
-                    .path()
-                    .strip_prefix(&input_dir)
-                    .expect("failed to strip prefix");
+            if entry.metadata().unwrap().is_dir() {
+                return Ok(());
+            }
+            println!("File: {}", entry.path().to_string_lossy());
+
+            if !entry.file_name().to_string_lossy().ends_with(".ts")
+                && !entry.file_name().to_string_lossy().ends_with(".js")
+                && !entry.file_name().to_string_lossy().ends_with(".jsx")
+                && !entry.file_name().to_string_lossy().ends_with(".tsx")
+            {
+                return Ok(());
+            }
 
-                let fm = cm.load_file(entry.path()).expect("failed to load file");
-                match c.process_js_file(
-                    fm,
-                    &handler,
-                    &Options {
-                        swcrc: true,
-                        output_path: Some(output.join(entry.file_name())),
-                        config: Config {
-                            jsc: JscConfig {
-                                external_helpers: true.into(),
-                                ..Default::default()
-                            },
-                            is_module: Some(IsModule::Unknown),
+            let rel_path = entry
+                .path()
+                .strip_prefix(&input_dir)
+                .expect("failed to strip prefix");
+
+            let fm = cm.load_file(entry.path()).expect("failed to load file");
+            match c.process_js_file(
+                fm,
+                &handler,
+                &Options {
+                    swcrc: true,
+                    output_path: Some(output_dir.join(entry.file_name())),
+                    config: Config {
+                        jsc: JscConfig {
+                            external_helpers: true.into(),
                             ..Default::default()
                         },
-
+                        is_module,
                         ..Default::default()
                     },
-                ) {
-                    Ok(v) => {
-                        NormalizedOutput::from(v.code)
-                            .compare_to_file(output.join(rel_path))
-                            .unwrap();
-
-                        let _ = create_dir_all(output.join(rel_path).parent().unwrap());
-
-                        let map = v.map.map(|json| {
-                            let json: serde_json::Value = serde_json::from_str(&json).unwrap();
-                            serde_json::to_string_pretty(&json).unwrap()
-                        });
-
-                        NormalizedOutput::from(map.unwrap_or_default())
-                            .compare_to_file(
-                                output.join(rel_path.with_extension("map").file_name().unwrap()),
-                            )
-                            .unwrap();
+
+                    ..Default::default()
+                },
+            ) {
+                Ok(v) => {
+                    NormalizedOutput::from(v.code)
+                        .compare_to_file(output_dir.join(rel_path))
+                        .unwrap();
+
+                    let _ = create_dir_all(output_dir.join(rel_path).parent().unwrap());
+
+                    let map = v.map.map(|json| {
+                        let json: serde_json::Value = serde_json::from_str(&json).unwrap();
+                        serde_json::to_string_pretty(&json).unwrap()
+                    });
+
+                    NormalizedOutput::from(map.unwrap_or_default())
+                        .compare_to_file(
+                            output_dir.join(rel_path.with_extension("map").file_name().unwrap()),
+                        )
+                        .unwrap();
+
+                    if let Some(extra) = v.output {
+                        let mut value: serde_json::Map<_, serde_json::Value> =
+                            serde_json::from_str(&extra).unwrap();
+
+                        if let Some(v) = value.remove("__swc_isolated_declarations__") {
+                            let code = v
+                                .as_str()
+                                .expect("isolated declaration pass should emit string");
+
+                            NormalizedOutput::from(code.to_string())
+                                .compare_to_file(output_dir.join(rel_path).with_extension("d.ts"))
+                                .unwrap();
+                        }
+
+                        if !value.is_empty() {
+                            let extra = serde_json::to_string_pretty(&value).unwrap();
+
+                            NormalizedOutput::from(extra)
+                                .compare_to_file(
+                                    output_dir.join(rel_path.with_extension("extra.json")),
+                                )
+                                .unwrap();
+                        }
                     }
-                    Err(ref err) if format!("{:?}", err).contains("not matched") => {}
-                    Err(ref err) if format!("{:?}", err).contains("Syntax Error") => return Err(()),
-                    Err(err) => panic!("Error: {:?}", err),
                 }
+                Err(ref err) if format!("{:?}", err).contains("not matched") => {}
+                Err(ref err) if format!("{:?}", err).contains("Syntax Error") => return Err(()),
+                Err(err) => panic!("Error: {:?}", err),
+            }
+            if handler.has_errors() {
+                Err(())
+            } else {
+                Ok(())
             }
+        });
 
-            Ok(())
-        })
-        .map(|_| ())
-        .expect("failed");
+        if let Err(err) = errors {
+            err.compare_to_file(output_dir.join(entry.path().with_extension("swc-stderr")))
+                .unwrap();
+        }
+    }
 }
 
 #[test]
diff --git a/crates/swc/tests/ts-isolated-declaration/error/.swcrc b/crates/swc/tests/ts-isolated-declaration/error/.swcrc
new file mode 100644
index 000000000000..a3fd28ebeca0
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/error/.swcrc
@@ -0,0 +1,10 @@
+{
+    "jsc": {
+        "parser": {
+            "syntax": "typescript"
+        },
+        "experimental": {
+            "emitIsolatedDts": true
+        }
+    }
+}
\ No newline at end of file
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/README.md b/crates/swc/tests/ts-isolated-declaration/oxc/README.md
new file mode 100644
index 000000000000..c7654306170e
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/README.md
@@ -0,0 +1,3 @@
+### TypeScript Isolated Declaration test cases
+
+These tests are copied from [oxc](https://github.com/oxc-project/oxc/tree/58e54f4aea89c5d548c7976caba80a484260a979/crates/oxc_isolated_declarations/tests/fixtures)
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/input/.swcrc b/crates/swc/tests/ts-isolated-declaration/oxc/input/.swcrc
new file mode 100644
index 000000000000..e9f895b14bf1
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/input/.swcrc
@@ -0,0 +1,11 @@
+{
+    "jsc": {
+        "parser": {
+            "syntax": "typescript"
+        },
+        "experimental": {
+            "emitIsolatedDts": true
+        }
+    },
+    "isModule": true
+}
\ No newline at end of file
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/input/arrow-function-return-type.ts b/crates/swc/tests/ts-isolated-declaration/oxc/input/arrow-function-return-type.ts
new file mode 100644
index 000000000000..34e91d499ce7
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/input/arrow-function-return-type.ts
@@ -0,0 +1,9 @@
+function A() {
+  return () => {
+    return C;
+  }
+}
+
+const B = () => { return B };
+
+const C = function () {}
\ No newline at end of file
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/input/as-const.swc-stderr b/crates/swc/tests/ts-isolated-declaration/oxc/input/as-const.swc-stderr
new file mode 100644
index 000000000000..ac88288403f8
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/input/as-const.swc-stderr
@@ -0,0 +1,16 @@
+
+  x unable to infer type from object property, skipping
+    ,-[$DIR/tests/ts-isolated-declaration/oxc/input/as-const.ts:8:1]
+  8 |   undefined: undefined,
+  9 |   function(a: string): void {},
+    :   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ 10 |   arrow: (a: string): void => {},
+    `----
+
+  x unable to infer type from expression or declaration
+    ,-[$DIR/tests/ts-isolated-declaration/oxc/input/as-const.ts:14:1]
+ 14 |   },
+ 15 |   array: [`a`, , { b: `\n` }],
+    :           ^^^
+ 16 | } as const
+    `----
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/input/as-const.ts b/crates/swc/tests/ts-isolated-declaration/oxc/input/as-const.ts
new file mode 100644
index 000000000000..b9638532cfa2
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/input/as-const.ts
@@ -0,0 +1,16 @@
+const F = {
+  string: `string`,
+  templateLiteral: `templateLiteral`,
+  number: 1.23,
+  bigint: -1_2_3n,
+  boolean: true,
+  null: null,
+  undefined: undefined,
+  function(a: string): void {},
+  arrow: (a: string): void => {},
+  object: {
+    a: `a`,
+    b: `b`
+  },
+  array: [`a`, , { b: `\n` }],
+} as const
\ No newline at end of file
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/input/async-function.ts b/crates/swc/tests/ts-isolated-declaration/oxc/input/async-function.ts
new file mode 100644
index 000000000000..3927f10d1e10
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/input/async-function.ts
@@ -0,0 +1,16 @@
+// Correct
+async function asyncFunctionGood(): Promise<number> {}
+const asyncFunctionGoo2 = async (): Promise<number> => {
+  return Promise.resolve(0);
+}
+
+
+// Need to explicit return type for async functions
+// Incorrect
+async function asyncFunction() {
+  return 42;
+}
+
+const asyncFunction2 = async () => {
+  return "Hello, World!";
+}
\ No newline at end of file
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/input/eliminate-imports.ts b/crates/swc/tests/ts-isolated-declaration/oxc/input/eliminate-imports.ts
new file mode 100644
index 000000000000..d068215c2484
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/input/eliminate-imports.ts
@@ -0,0 +1,7 @@
+import { AExtend, BExtend, Type, CImplements1, CImplements2, CType, ThisType1, ThisType2, Unused } from 'mod';
+
+export interface A extends AExtend<Type> {}
+export class B extends BExtend<Type> {}
+export class C implements CImplements1<CType>, CImplements2<CType> {}
+export function foo(this: ThisType1): void {}
+export const bar: (this: ThisType2) => void = function() {}
\ No newline at end of file
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/input/empty-export.ts b/crates/swc/tests/ts-isolated-declaration/oxc/input/empty-export.ts
new file mode 100644
index 000000000000..4d1ef02d37e9
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/input/empty-export.ts
@@ -0,0 +1,4 @@
+type A = string;
+export function a(): A {
+  return ""
+}
\ No newline at end of file
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/input/function-overloads.swc-stderr b/crates/swc/tests/ts-isolated-declaration/oxc/input/function-overloads.swc-stderr
new file mode 100644
index 000000000000..61d586dad664
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/input/function-overloads.swc-stderr
@@ -0,0 +1,11 @@
+
+  x the name `b` is defined multiple times
+   ,-[$DIR/tests/ts-isolated-declaration/oxc/input/function-overloads.ts:5:1]
+ 5 | 
+ 6 | function b(a: number): number {};
+   :          |
+   :          `-- previous definition of `b` here
+ 7 | function b(a: string): string {};
+   :          |
+   :          `-- `b` redefined here
+   `----
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/input/function-overloads.ts b/crates/swc/tests/ts-isolated-declaration/oxc/input/function-overloads.ts
new file mode 100644
index 000000000000..e33f9a36e753
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/input/function-overloads.ts
@@ -0,0 +1,7 @@
+function a(a: number): number;
+function a(a: string): string;
+function a(a: any): any {}
+
+
+function b(a: number): number {};
+function b(a: string): string {};
\ No newline at end of file
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/input/function-parameters.ts b/crates/swc/tests/ts-isolated-declaration/oxc/input/function-parameters.ts
new file mode 100644
index 000000000000..b43e3dfcb388
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/input/function-parameters.ts
@@ -0,0 +1,24 @@
+// Correct
+export function fnDeclGood(p: T = [], rParam = ""): void { };
+export function fnDeclGood2(p: T = [], rParam?: number): void { };
+
+export function fooGood([a, b]: any[] = [1, 2]): number {
+  return 2;
+}
+
+export const fooGood2 = ({a, b}: object = { a: 1, b: 2 }): number => {
+  return 2;
+}
+
+// Incorrect
+export function fnDeclBad<T>(p: T = [], rParam: T = "", r2: T): void { }
+export function fnDeclBad2<T>(p: T = [], r2: T): void { }
+export function fnDeclBad3<T>(p: T = [], rParam?: T, r2: T): void { }
+
+export function fooBad([a, b] = [1, 2]): number {
+  return 2;
+}
+
+export const fooBad2 = ({a, b} = { a: 1, b: 2 }): number => {
+  return 2;
+}
\ No newline at end of file
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/input/generator.ts b/crates/swc/tests/ts-isolated-declaration/oxc/input/generator.ts
new file mode 100644
index 000000000000..c09739a260a9
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/input/generator.ts
@@ -0,0 +1,10 @@
+// Correct
+function *generatorGood(): Generator<number> {}
+
+
+// Need to explicit return type for async functions
+// Incorrect
+function *generatorGoodBad() {
+  yield 50;
+  return 42;
+}
\ No newline at end of file
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/input/infer-expression.swc-stderr b/crates/swc/tests/ts-isolated-declaration/oxc/input/infer-expression.swc-stderr
new file mode 100644
index 000000000000..f51225ab2254
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/input/infer-expression.swc-stderr
@@ -0,0 +1,31 @@
+
+  x unable to infer type, falling back to any type
+   ,-[$DIR/tests/ts-isolated-declaration/oxc/input/infer-expression.ts:1:1]
+ 1 | // ParenthesizedExpression
+ 2 | const n = (0);
+   :       ^
+ 3 | const s = ("");
+   `----
+
+  x unable to infer type, falling back to any type
+   ,-[$DIR/tests/ts-isolated-declaration/oxc/input/infer-expression.ts:2:1]
+ 2 | const n = (0);
+ 3 | const s = ("");
+   :       ^
+ 4 | const t = (``);
+   `----
+
+  x unable to infer type, falling back to any type
+   ,-[$DIR/tests/ts-isolated-declaration/oxc/input/infer-expression.ts:3:1]
+ 3 | const s = ("");
+ 4 | const t = (``);
+   :       ^
+ 5 | const b = (true);
+   `----
+
+  x unable to infer type, falling back to any type
+   ,-[$DIR/tests/ts-isolated-declaration/oxc/input/infer-expression.ts:4:1]
+ 4 | const t = (``);
+ 5 | const b = (true);
+   :       ^
+   `----
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/input/infer-expression.ts b/crates/swc/tests/ts-isolated-declaration/oxc/input/infer-expression.ts
new file mode 100644
index 000000000000..06222db62bcc
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/input/infer-expression.ts
@@ -0,0 +1,5 @@
+// ParenthesizedExpression
+const n = (0);
+const s = ("");
+const t = (``);
+const b = (true);
\ No newline at end of file
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/input/infer-return-type.ts b/crates/swc/tests/ts-isolated-declaration/oxc/input/infer-return-type.ts
new file mode 100644
index 000000000000..dde956921836
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/input/infer-return-type.ts
@@ -0,0 +1,27 @@
+function foo() {
+   return 1;
+}
+// inferred type is number
+
+function bar() {
+  if (a) {
+   return;
+  }
+  return 1;
+}
+// inferred type is number | undefined
+
+function baz() {
+ if (a) {
+  return null;
+ }
+ return 1;
+}
+// We can't infer return type if there are multiple return statements with different types
+
+function qux() {
+  const a = (() => {
+    return 1;
+  })();
+ return `Hello, world!`;
+}
\ No newline at end of file
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/input/infer-template-literal.swc-stderr b/crates/swc/tests/ts-isolated-declaration/oxc/input/infer-template-literal.swc-stderr
new file mode 100644
index 000000000000..9bfecee378ad
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/input/infer-template-literal.swc-stderr
@@ -0,0 +1,28 @@
+
+  x unable to infer type, falling back to any type
+   ,-[$DIR/tests/ts-isolated-declaration/oxc/input/infer-template-literal.ts:1:1]
+ 1 | export const CSS_VARS_HELPER = `useCssVars`
+   :              ^^^^^^^^^^^^^^^
+   `----
+
+  x unable to infer type, falling back to any type
+   ,-[$DIR/tests/ts-isolated-declaration/oxc/input/infer-template-literal.ts:2:1]
+ 2 | 
+ 3 | export function g(func = `useCssVar`) : void {}
+   :                          ^^^^^^^^^^^
+   `----
+
+  x unable to infer type from expression or declaration
+   ,-[$DIR/tests/ts-isolated-declaration/oxc/input/infer-template-literal.ts:6:1]
+ 6 |   a: `a`,
+ 7 |   b: [`b`]
+   :       ^^^
+ 8 | } as const
+   `----
+
+  x unable to infer type, falling back to any type
+    ,-[$DIR/tests/ts-isolated-declaration/oxc/input/infer-template-literal.ts:9:1]
+  9 | 
+ 10 | export const BAD = `useCssV${v}ars`
+    :              ^^^
+    `----
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/input/infer-template-literal.ts b/crates/swc/tests/ts-isolated-declaration/oxc/input/infer-template-literal.ts
new file mode 100644
index 000000000000..875168425145
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/input/infer-template-literal.ts
@@ -0,0 +1,10 @@
+export const CSS_VARS_HELPER = `useCssVars`
+
+export function g(func = `useCssVar`) : void {}
+
+export const F = {
+  a: `a`,
+  b: [`b`]
+} as const
+
+export const BAD = `useCssV${v}ars`
\ No newline at end of file
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/input/non-exported-binding-elements.swc-stderr b/crates/swc/tests/ts-isolated-declaration/oxc/input/non-exported-binding-elements.swc-stderr
new file mode 100644
index 000000000000..d8141c8f5678
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/input/non-exported-binding-elements.swc-stderr
@@ -0,0 +1,24 @@
+
+  x unable to infer type from expression or declaration
+   ,-[$DIR/tests/ts-isolated-declaration/oxc/input/non-exported-binding-elements.ts:1:1]
+ 1 | // Correct
+ 2 | const [A, B] = [1, 2, 3];
+   :       ^^^^^^^^^^^^^^^^^^
+ 3 | export function foo(): number {
+   `----
+
+  x unable to infer type from expression or declaration
+   ,-[$DIR/tests/ts-isolated-declaration/oxc/input/non-exported-binding-elements.ts:7:1]
+ 7 | // Incorrect
+ 8 | const { c, d } = { c: 1, d: 2 };
+   :       ^^^^^^^^^^^^^^^^^^^^^^^^^
+ 9 | const [ e ] = [4];
+   `----
+
+  x unable to infer type from expression or declaration
+    ,-[$DIR/tests/ts-isolated-declaration/oxc/input/non-exported-binding-elements.ts:8:1]
+  8 | const { c, d } = { c: 1, d: 2 };
+  9 | const [ e ] = [4];
+    :       ^^^^^^^^^^^
+ 10 | export { c, d, e }
+    `----
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/input/non-exported-binding-elements.ts b/crates/swc/tests/ts-isolated-declaration/oxc/input/non-exported-binding-elements.ts
new file mode 100644
index 000000000000..0e41ea05a2fc
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/input/non-exported-binding-elements.ts
@@ -0,0 +1,10 @@
+// Correct
+const [A, B] = [1, 2, 3];
+export function foo(): number {
+    return A;
+}
+
+// Incorrect
+const { c, d } = { c: 1, d: 2 };
+const [ e ] = [4];
+export { c, d, e }
\ No newline at end of file
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/input/readonly.ts b/crates/swc/tests/ts-isolated-declaration/oxc/input/readonly.ts
new file mode 100644
index 000000000000..a2387f95519d
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/input/readonly.ts
@@ -0,0 +1,4 @@
+export const EMPTY_OBJ: { readonly [key: string]: any } = __DEV__
+  ? Object.freeze({})
+  : {}
+export const EMPTY_ARR: readonly never[] = __DEV__ ? Object.freeze([]) : []
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/output/arrow-function-return-type.d.ts b/crates/swc/tests/ts-isolated-declaration/oxc/output/arrow-function-return-type.d.ts
new file mode 100644
index 000000000000..951863507897
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/output/arrow-function-return-type.d.ts
@@ -0,0 +1,3 @@
+declare function A();
+declare const B: () => any;
+declare const C: () => any;
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/output/arrow-function-return-type.ts b/crates/swc/tests/ts-isolated-declaration/oxc/output/arrow-function-return-type.ts
new file mode 100644
index 000000000000..daf3943a3c23
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/output/arrow-function-return-type.ts
@@ -0,0 +1,9 @@
+function A() {
+    return function() {
+        return C;
+    };
+}
+var B = function() {
+    return B;
+};
+var C = function C() {};
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/output/as-const.d.ts b/crates/swc/tests/ts-isolated-declaration/oxc/output/as-const.d.ts
new file mode 100644
index 000000000000..fc37e01ed33e
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/output/as-const.d.ts
@@ -0,0 +1,17 @@
+declare const F: {
+    readonly string;
+    readonly templateLiteral;
+    readonly number: 1.23;
+    readonly bigint;
+    readonly boolean: true;
+    readonly null: null;
+    readonly undefined;
+    readonly arrow: (a: string) => void;
+    readonly object: {
+        readonly a;
+        readonly b;
+    };
+    readonly array: readonly [any, {
+            readonly b;
+        }];
+};
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/output/as-const.ts b/crates/swc/tests/ts-isolated-declaration/oxc/output/as-const.ts
new file mode 100644
index 000000000000..acd2c029e23d
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/output/as-const.ts
@@ -0,0 +1,22 @@
+var F = {
+    string: "string",
+    templateLiteral: "templateLiteral",
+    number: 1.23,
+    bigint: -123n,
+    boolean: true,
+    null: null,
+    undefined: undefined,
+    function: function _function(a) {},
+    arrow: function(a) {},
+    object: {
+        a: "a",
+        b: "b"
+    },
+    array: [
+        "a",
+        ,
+        {
+            b: "\n"
+        }
+    ]
+};
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/output/async-function.d.ts b/crates/swc/tests/ts-isolated-declaration/oxc/output/async-function.d.ts
new file mode 100644
index 000000000000..f53fab55e8b1
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/output/async-function.d.ts
@@ -0,0 +1,4 @@
+declare async function asyncFunctionGood(): Promise<number>;
+declare const asyncFunctionGoo2: () => Promise<number>;
+declare async function asyncFunction();
+declare const asyncFunction2: () => any;
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/output/async-function.ts b/crates/swc/tests/ts-isolated-declaration/oxc/output/async-function.ts
new file mode 100644
index 000000000000..f5588800c7ff
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/output/async-function.ts
@@ -0,0 +1,58 @@
+// Correct
+import { _ as _async_to_generator } from "@swc/helpers/_/_async_to_generator";
+import { _ as _ts_generator } from "@swc/helpers/_/_ts_generator";
+function asyncFunctionGood() {
+    return _asyncFunctionGood.apply(this, arguments);
+}
+function _asyncFunctionGood() {
+    _asyncFunctionGood = _async_to_generator(function() {
+        return _ts_generator(this, function(_state) {
+            return [
+                2
+            ];
+        });
+    });
+    return _asyncFunctionGood.apply(this, arguments);
+}
+var asyncFunctionGoo2 = function() {
+    var _ref = _async_to_generator(function() {
+        return _ts_generator(this, function(_state) {
+            return [
+                2,
+                Promise.resolve(0)
+            ];
+        });
+    });
+    return function asyncFunctionGoo2() {
+        return _ref.apply(this, arguments);
+    };
+}();
+function asyncFunction() {
+    return _asyncFunction.apply(this, arguments);
+}
+function _asyncFunction() {
+    _asyncFunction = // Need to explicit return type for async functions
+    // Incorrect
+    _async_to_generator(function() {
+        return _ts_generator(this, function(_state) {
+            return [
+                2,
+                42
+            ];
+        });
+    });
+    return _asyncFunction.apply(this, arguments);
+}
+var asyncFunction2 = function() {
+    var _ref = _async_to_generator(function() {
+        return _ts_generator(this, function(_state) {
+            return [
+                2,
+                "Hello, World!"
+            ];
+        });
+    });
+    return function asyncFunction2() {
+        return _ref.apply(this, arguments);
+    };
+}();
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/output/eliminate-imports.d.ts b/crates/swc/tests/ts-isolated-declaration/oxc/output/eliminate-imports.d.ts
new file mode 100644
index 000000000000..90c532519b12
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/output/eliminate-imports.d.ts
@@ -0,0 +1,9 @@
+import { AExtend, BExtend, Type, CImplements1, CImplements2, CType, ThisType1, ThisType2, Unused } from 'mod';
+export interface A extends AExtend<Type> {
+}
+export declare class B extends BExtend<Type> {
+}
+export declare class C implements CImplements1<CType>, CImplements2<CType> {
+}
+export declare function foo(this: ThisType1): void;
+export declare const bar: (this: ThisType2) => void;
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/output/eliminate-imports.ts b/crates/swc/tests/ts-isolated-declaration/oxc/output/eliminate-imports.ts
new file mode 100644
index 000000000000..00d67d46d19c
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/output/eliminate-imports.ts
@@ -0,0 +1,20 @@
+import { _ as _class_call_check } from "@swc/helpers/_/_class_call_check";
+import { _ as _inherits } from "@swc/helpers/_/_inherits";
+import { _ as _create_super } from "@swc/helpers/_/_create_super";
+import { BExtend } from 'mod';
+export var B = /*#__PURE__*/ function(BExtend) {
+    "use strict";
+    _inherits(B, BExtend);
+    var _super = _create_super(B);
+    function B() {
+        _class_call_check(this, B);
+        return _super.apply(this, arguments);
+    }
+    return B;
+}(BExtend);
+export var C = function C() {
+    "use strict";
+    _class_call_check(this, C);
+};
+export function foo() {}
+export var bar = function bar() {};
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/output/empty-export.d.ts b/crates/swc/tests/ts-isolated-declaration/oxc/output/empty-export.d.ts
new file mode 100644
index 000000000000..309ce472bdfe
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/output/empty-export.d.ts
@@ -0,0 +1,2 @@
+type A = string;
+export declare function a(): A;
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/output/empty-export.ts b/crates/swc/tests/ts-isolated-declaration/oxc/output/empty-export.ts
new file mode 100644
index 000000000000..48bfc02227dc
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/output/empty-export.ts
@@ -0,0 +1,3 @@
+export function a() {
+    return "";
+}
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/output/function-overloads.d.ts b/crates/swc/tests/ts-isolated-declaration/oxc/output/function-overloads.d.ts
new file mode 100644
index 000000000000..dfdebec2b39a
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/output/function-overloads.d.ts
@@ -0,0 +1,5 @@
+declare function a(a: number): number;
+declare function a(a: string): string;
+declare function a(a: any): any;
+declare function b(a: number): number;
+declare function b(a: string): string;
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/output/function-overloads.ts b/crates/swc/tests/ts-isolated-declaration/oxc/output/function-overloads.ts
new file mode 100644
index 000000000000..4811e22fa8bb
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/output/function-overloads.ts
@@ -0,0 +1,3 @@
+function a(a) {}
+function b(a) {}
+function b(a) {}
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/output/function-parameters.d.ts b/crates/swc/tests/ts-isolated-declaration/oxc/output/function-parameters.d.ts
new file mode 100644
index 000000000000..facbc14cbd0a
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/output/function-parameters.d.ts
@@ -0,0 +1,15 @@
+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: (_dts_1: {
+    a: number;
+    b: number;
+}) => number;
+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;
+export declare function fooBad([a, b]?: [number, number]): number;
+export declare const fooBad2: (_dts_2: {
+    a: number;
+    b: number;
+}) => number;
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/output/function-parameters.ts b/crates/swc/tests/ts-isolated-declaration/oxc/output/function-parameters.ts
new file mode 100644
index 000000000000..8283cd79cee5
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/output/function-parameters.ts
@@ -0,0 +1,46 @@
+// Correct
+import { _ as _sliced_to_array } from "@swc/helpers/_/_sliced_to_array";
+export function fnDeclGood() {
+    var p = arguments.length > 0 && arguments[0] !== void 0 ? arguments[0] : [], rParam = arguments.length > 1 && arguments[1] !== void 0 ? arguments[1] : "";
+}
+export function fnDeclGood2() {
+    var p = arguments.length > 0 && arguments[0] !== void 0 ? arguments[0] : [], rParam = arguments.length > 1 ? arguments[1] : void 0;
+}
+export function fooGood() {
+    var _ref = _sliced_to_array(arguments.length > 0 && arguments[0] !== void 0 ? arguments[0] : [
+        1,
+        2
+    ], 2), a = _ref[0], b = _ref[1];
+    return 2;
+}
+export var fooGood2 = function() {
+    var _ref = arguments.length > 0 && arguments[0] !== void 0 ? arguments[0] : {
+        a: 1,
+        b: 2
+    }, a = _ref.a, b = _ref.b;
+    return 2;
+};
+// Incorrect
+export function fnDeclBad() {
+    var p = arguments.length > 0 && arguments[0] !== void 0 ? arguments[0] : [], rParam = arguments.length > 1 && arguments[1] !== void 0 ? arguments[1] : "", r2 = arguments.length > 2 ? arguments[2] : void 0;
+}
+export function fnDeclBad2() {
+    var p = arguments.length > 0 && arguments[0] !== void 0 ? arguments[0] : [], r2 = arguments.length > 1 ? arguments[1] : void 0;
+}
+export function fnDeclBad3() {
+    var p = arguments.length > 0 && arguments[0] !== void 0 ? arguments[0] : [], rParam = arguments.length > 1 ? arguments[1] : void 0, r2 = arguments.length > 2 ? arguments[2] : void 0;
+}
+export function fooBad() {
+    var _ref = _sliced_to_array(arguments.length > 0 && arguments[0] !== void 0 ? arguments[0] : [
+        1,
+        2
+    ], 2), a = _ref[0], b = _ref[1];
+    return 2;
+}
+export var fooBad2 = function() {
+    var _ref = arguments.length > 0 && arguments[0] !== void 0 ? arguments[0] : {
+        a: 1,
+        b: 2
+    }, a = _ref.a, b = _ref.b;
+    return 2;
+};
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/output/generator.d.ts b/crates/swc/tests/ts-isolated-declaration/oxc/output/generator.d.ts
new file mode 100644
index 000000000000..343e7e950f92
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/output/generator.d.ts
@@ -0,0 +1,2 @@
+declare function* generatorGood(): Generator<number>;
+declare function* generatorGoodBad();
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/output/generator.ts b/crates/swc/tests/ts-isolated-declaration/oxc/output/generator.ts
new file mode 100644
index 000000000000..3a0d81551227
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/output/generator.ts
@@ -0,0 +1,28 @@
+// Correct
+import { _ as _ts_generator } from "@swc/helpers/_/_ts_generator";
+function generatorGood() {
+    return _ts_generator(this, function(_state) {
+        return [
+            2
+        ];
+    });
+}
+// Need to explicit return type for async functions
+// Incorrect
+function generatorGoodBad() {
+    return _ts_generator(this, function(_state) {
+        switch(_state.label){
+            case 0:
+                return [
+                    4,
+                    50
+                ];
+            case 1:
+                _state.sent();
+                return [
+                    2,
+                    42
+                ];
+        }
+    });
+}
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/output/infer-expression.d.ts b/crates/swc/tests/ts-isolated-declaration/oxc/output/infer-expression.d.ts
new file mode 100644
index 000000000000..a9884bfb02a7
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/output/infer-expression.d.ts
@@ -0,0 +1,4 @@
+declare const n: any;
+declare const s: any;
+declare const t: any;
+declare const b: any;
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/output/infer-expression.ts b/crates/swc/tests/ts-isolated-declaration/oxc/output/infer-expression.ts
new file mode 100644
index 000000000000..d0da18cac621
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/output/infer-expression.ts
@@ -0,0 +1,5 @@
+// ParenthesizedExpression
+var n = 0;
+var s = "";
+var t = "";
+var b = true;
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/output/infer-return-type.d.ts b/crates/swc/tests/ts-isolated-declaration/oxc/output/infer-return-type.d.ts
new file mode 100644
index 000000000000..ba834d2b51b8
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/output/infer-return-type.d.ts
@@ -0,0 +1,4 @@
+declare function foo();
+declare function bar();
+declare function baz();
+declare function qux();
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/output/infer-return-type.ts b/crates/swc/tests/ts-isolated-declaration/oxc/output/infer-return-type.ts
new file mode 100644
index 000000000000..798b94c4e665
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/output/infer-return-type.ts
@@ -0,0 +1,24 @@
+function foo() {
+    return 1;
+}
+// inferred type is number
+function bar() {
+    if (a) {
+        return;
+    }
+    return 1;
+}
+// inferred type is number | undefined
+function baz() {
+    if (a) {
+        return null;
+    }
+    return 1;
+}
+// We can't infer return type if there are multiple return statements with different types
+function qux() {
+    var a1 = function() {
+        return 1;
+    }();
+    return "Hello, world!";
+}
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/output/infer-template-literal.d.ts b/crates/swc/tests/ts-isolated-declaration/oxc/output/infer-template-literal.d.ts
new file mode 100644
index 000000000000..adb8c69e9d64
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/output/infer-template-literal.d.ts
@@ -0,0 +1,7 @@
+export declare const CSS_VARS_HELPER: any;
+export declare function g(func?: any): void;
+export declare const F: {
+    readonly a;
+    readonly b: readonly [];
+};
+export declare const BAD: any;
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/output/infer-template-literal.ts b/crates/swc/tests/ts-isolated-declaration/oxc/output/infer-template-literal.ts
new file mode 100644
index 000000000000..0f140f996665
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/output/infer-template-literal.ts
@@ -0,0 +1,11 @@
+export var CSS_VARS_HELPER = "useCssVars";
+export function g() {
+    var func = arguments.length > 0 && arguments[0] !== void 0 ? arguments[0] : "useCssVar";
+}
+export var F = {
+    a: "a",
+    b: [
+        "b"
+    ]
+};
+export var BAD = "useCssV".concat(v, "ars");
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/output/non-exported-binding-elements.d.ts b/crates/swc/tests/ts-isolated-declaration/oxc/output/non-exported-binding-elements.d.ts
new file mode 100644
index 000000000000..b1eb175014d7
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/output/non-exported-binding-elements.d.ts
@@ -0,0 +1,5 @@
+declare const [A, B];
+export declare function foo(): number;
+declare const { c, d };
+declare const [e];
+export { c, d, e };
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/output/non-exported-binding-elements.ts b/crates/swc/tests/ts-isolated-declaration/oxc/output/non-exported-binding-elements.ts
new file mode 100644
index 000000000000..8da8a1229c59
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/output/non-exported-binding-elements.ts
@@ -0,0 +1,16 @@
+// Correct
+var _ref = [
+    1,
+    2,
+    3
+], A = _ref[0], B = _ref[1];
+export function foo() {
+    return A;
+}
+// Incorrect
+var _ref1 = {
+    c: 1,
+    d: 2
+}, c = _ref1.c, d = _ref1.d;
+var e = 4;
+export { c, d, e };
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/output/readonly.d.ts b/crates/swc/tests/ts-isolated-declaration/oxc/output/readonly.d.ts
new file mode 100644
index 000000000000..bbf1f8e3625a
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/output/readonly.d.ts
@@ -0,0 +1,4 @@
+export declare const EMPTY_OBJ: {
+    readonly [key: string]: any;
+};
+export declare const EMPTY_ARR: readonly never[];
diff --git a/crates/swc/tests/ts-isolated-declaration/oxc/output/readonly.ts b/crates/swc/tests/ts-isolated-declaration/oxc/output/readonly.ts
new file mode 100644
index 000000000000..7f23a96b883a
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/oxc/output/readonly.ts
@@ -0,0 +1,2 @@
+export var EMPTY_OBJ = __DEV__ ? Object.freeze({}) : {};
+export var EMPTY_ARR = __DEV__ ? Object.freeze([]) : [];
diff --git a/crates/swc/tests/ts-isolated-declaration/simple/.swcrc b/crates/swc/tests/ts-isolated-declaration/simple/.swcrc
new file mode 100644
index 000000000000..a3fd28ebeca0
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/simple/.swcrc
@@ -0,0 +1,10 @@
+{
+    "jsc": {
+        "parser": {
+            "syntax": "typescript"
+        },
+        "experimental": {
+            "emitIsolatedDts": true
+        }
+    }
+}
\ No newline at end of file
diff --git a/crates/swc/tests/ts-isolated-declaration/simple/input/1.ts b/crates/swc/tests/ts-isolated-declaration/simple/input/1.ts
new file mode 100644
index 000000000000..2a9e319419a1
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/simple/input/1.ts
@@ -0,0 +1,4 @@
+
+
+
+export const foo = 1
\ No newline at end of file
diff --git a/crates/swc/tests/ts-isolated-declaration/simple/input/2.ts b/crates/swc/tests/ts-isolated-declaration/simple/input/2.ts
new file mode 100644
index 000000000000..17ec04052ef9
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/simple/input/2.ts
@@ -0,0 +1 @@
+export var foo: number = "abc";
\ No newline at end of file
diff --git a/crates/swc/tests/ts-isolated-declaration/simple/input/3.ts b/crates/swc/tests/ts-isolated-declaration/simple/input/3.ts
new file mode 100644
index 000000000000..5c69209cbaca
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/simple/input/3.ts
@@ -0,0 +1 @@
+export enum Foo { A = "foo", B = "bar" }
\ No newline at end of file
diff --git a/crates/swc/tests/ts-isolated-declaration/simple/output/1.d.ts b/crates/swc/tests/ts-isolated-declaration/simple/output/1.d.ts
new file mode 100644
index 000000000000..938bee8e82b2
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/simple/output/1.d.ts
@@ -0,0 +1 @@
+export declare const foo: number;
diff --git a/crates/swc/tests/ts-isolated-declaration/simple/output/1.ts b/crates/swc/tests/ts-isolated-declaration/simple/output/1.ts
new file mode 100644
index 000000000000..e2e71aa4fc6d
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/simple/output/1.ts
@@ -0,0 +1 @@
+export var foo = 1;
diff --git a/crates/swc/tests/ts-isolated-declaration/simple/output/2.d.ts b/crates/swc/tests/ts-isolated-declaration/simple/output/2.d.ts
new file mode 100644
index 000000000000..84b0663ba9f9
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/simple/output/2.d.ts
@@ -0,0 +1 @@
+export declare var foo: number;
diff --git a/crates/swc/tests/ts-isolated-declaration/simple/output/2.ts b/crates/swc/tests/ts-isolated-declaration/simple/output/2.ts
new file mode 100644
index 000000000000..9e51ee25bcc2
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/simple/output/2.ts
@@ -0,0 +1 @@
+export var foo = "abc";
diff --git a/crates/swc/tests/ts-isolated-declaration/simple/output/3.d.ts b/crates/swc/tests/ts-isolated-declaration/simple/output/3.d.ts
new file mode 100644
index 000000000000..cbcd170d1f9e
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/simple/output/3.d.ts
@@ -0,0 +1,4 @@
+export declare enum Foo {
+    A = "foo",
+    B = "bar"
+}
diff --git a/crates/swc/tests/ts-isolated-declaration/simple/output/3.ts b/crates/swc/tests/ts-isolated-declaration/simple/output/3.ts
new file mode 100644
index 000000000000..7adce2c72ff6
--- /dev/null
+++ b/crates/swc/tests/ts-isolated-declaration/simple/output/3.ts
@@ -0,0 +1,5 @@
+export var Foo;
+(function(Foo) {
+    Foo["A"] = "foo";
+    Foo["B"] = "bar";
+})(Foo || (Foo = {}));
diff --git a/crates/swc_typescript/src/diagnostic.rs b/crates/swc_typescript/src/diagnostic.rs
index 8e2261724eaa..45665fcd6ba9 100644
--- a/crates/swc_typescript/src/diagnostic.rs
+++ b/crates/swc_typescript/src/diagnostic.rs
@@ -5,7 +5,7 @@ use swc_common::{FileName, Span};
 #[derive(Debug, Clone)]
 pub struct SourceRange {
     pub filename: Arc<FileName>,
-    pub range: Span,
+    pub span: Span,
 }
 
 #[derive(Debug, Clone, thiserror::Error)]
@@ -23,13 +23,13 @@ pub enum DtsIssue {
 }
 
 impl DtsIssue {
-    pub fn range(&self) -> Option<&SourceRange> {
+    pub fn range(&self) -> &SourceRange {
         match self {
-            DtsIssue::UnableToInferType { range } => Some(range),
-            DtsIssue::UnableToInferTypeFallbackAny { range } => Some(range),
-            DtsIssue::UnableToInferTypeFromProp { range } => Some(range),
-            DtsIssue::UnableToInferTypeFromSpread { range } => Some(range),
-            DtsIssue::UnsupportedUsing { range } => Some(range),
+            DtsIssue::UnableToInferType { range } => range,
+            DtsIssue::UnableToInferTypeFallbackAny { range } => range,
+            DtsIssue::UnableToInferTypeFromProp { range } => range,
+            DtsIssue::UnableToInferTypeFromSpread { range } => range,
+            DtsIssue::UnsupportedUsing { range } => range,
         }
     }
 }
diff --git a/crates/swc_typescript/src/fast_dts/mod.rs b/crates/swc_typescript/src/fast_dts/mod.rs
index 9b78be5486dc..29129a8ad483 100644
--- a/crates/swc_typescript/src/fast_dts/mod.rs
+++ b/crates/swc_typescript/src/fast_dts/mod.rs
@@ -48,7 +48,7 @@ impl FastDts {
     fn source_range_to_range(&self, range: Span) -> SourceRange {
         SourceRange {
             filename: self.filename.clone(),
-            range,
+            span: range,
         }
     }