fix(isolated-declarations): private constructor reaching unreachable (#3921)

fix: #3917

crates/oxc_isolated_declarations/src/class.rs

@@ -202,7 +202,7 @@ impl<'a> IsolatedDeclarations<'a> {
                     self.transform_accessibility(method.accessibility),
                 )
             }
-            MethodDefinitionKind::Get => {
+            MethodDefinitionKind::Get | MethodDefinitionKind::Constructor => {
                 let params = self.ast.formal_parameters(
                     SPAN,
                     FormalParameterKind::Signature,
@@ -221,9 +221,6 @@ impl<'a> IsolatedDeclarations<'a> {
                 );
                 self.transform_class_method_definition(method, params, None)
             }
-            MethodDefinitionKind::Constructor => {
-                unreachable!()
-            }
         }
     }
 

crates/oxc_isolated_declarations/tests/fixtures/class.ts

@@ -0,0 +1,7 @@
+export class Foo {
+  private constructor(a: number = 0) {}
+}
+
+export class Bar {
+  public constructor(a: number = 0) {}
+}

crates/oxc_isolated_declarations/tests/snapshots/class.snap

@@ -0,0 +1,12 @@
+---
+source: crates/oxc_isolated_declarations/tests/mod.rs
+input_file: crates/oxc_isolated_declarations/tests/fixtures/class.ts
+---
+==================== .D.TS ====================
+
+export declare class Foo {
+	private constructor();
+}
+export declare class Bar {
+	constructor(a?: number);
+}