diff --git a/internal/transformers/declarations/transform.go b/internal/transformers/declarations/transform.go
index e81bf4f602..5e7d92a011 100644
--- a/internal/transformers/declarations/transform.go
+++ b/internal/transformers/declarations/transform.go
@@ -120,7 +120,8 @@ func (tx *DeclarationTransformer) visit(node *ast.Node) *ast.Node {
 		ast.KindJSImportDeclaration,
 		ast.KindExportDeclaration,
 		ast.KindJSExportAssignment,
-		ast.KindExportAssignment:
+		ast.KindExportAssignment,
+		ast.KindCommonJSExport:
 		return tx.visitDeclarationStatements(node)
 	// statements we elide
 	case ast.KindBreakStatement,
@@ -924,6 +925,80 @@ func (tx *DeclarationTransformer) visitDeclarationStatements(input *ast.Node) *a
 			tx.rewriteModuleSpecifier(input, input.AsExportDeclaration().ModuleSpecifier),
 			tx.tryGetResolutionModeOverride(input.AsExportDeclaration().Attributes),
 		)
+	case ast.KindCommonJSExport:
+		if ast.IsSourceFile(input.Parent) {
+			tx.resultHasExternalModuleIndicator = true
+		}
+		tx.resultHasScopeMarker = true
+		name := input.AsCommonJSExport().Name()
+		if ast.IsIdentifier(name) {
+			if name.AsIdentifier().Text == "default" {
+				// const _default: Type; export default _default;
+				newId := tx.Factory().NewUniqueNameEx("_default", printer.AutoGenerateOptions{Flags: printer.GeneratedIdentifierFlagsOptimistic})
+				tx.state.getSymbolAccessibilityDiagnostic = func(_ printer.SymbolAccessibilityResult) *SymbolAccessibilityDiagnostic {
+					return &SymbolAccessibilityDiagnostic{
+						diagnosticMessage: diagnostics.Default_export_of_the_module_has_or_is_using_private_name_0,
+						errorNode:         input,
+					}
+				}
+				tx.tracker.PushErrorFallbackNode(input)
+				type_ := tx.ensureType(input, false)
+				varDecl := tx.Factory().NewVariableDeclaration(newId, nil, type_, nil)
+				tx.tracker.PopErrorFallbackNode()
+				var modList *ast.ModifierList
+				if tx.needsDeclare {
+					modList = tx.Factory().NewModifierList([]*ast.Node{tx.Factory().NewModifier(ast.KindDeclareKeyword)})
+				} else {
+					modList = tx.Factory().NewModifierList([]*ast.Node{})
+				}
+				statement := tx.Factory().NewVariableStatement(modList, tx.Factory().NewVariableDeclarationList(ast.NodeFlagsConst, tx.Factory().NewNodeList([]*ast.Node{varDecl})))
+
+				assignment := tx.Factory().NewExportAssignment(input.Modifiers(), false, nil, newId)
+				// Remove comments from the export declaration and copy them onto the synthetic _default declaration
+				tx.preserveJsDoc(statement, input)
+				tx.removeAllComments(assignment)
+				return tx.Factory().NewSyntaxList([]*ast.Node{statement, assignment})
+			} else {
+				// export var name: Type
+				tx.tracker.PushErrorFallbackNode(input)
+				type_ := tx.ensureType(input, false)
+				varDecl := tx.Factory().NewVariableDeclaration(name, nil, type_, nil)
+				tx.tracker.PopErrorFallbackNode()
+				var modList *ast.ModifierList
+				if tx.needsDeclare {
+					modList = tx.Factory().NewModifierList([]*ast.Node{tx.Factory().NewModifier(ast.KindExportKeyword), tx.Factory().NewModifier(ast.KindDeclareKeyword)})
+				} else {
+					modList = tx.Factory().NewModifierList([]*ast.Node{tx.Factory().NewModifier(ast.KindExportKeyword)})
+				}
+				return tx.Factory().NewVariableStatement(modList, tx.Factory().NewVariableDeclarationList(ast.NodeFlagsNone, tx.Factory().NewNodeList([]*ast.Node{varDecl})))
+			}
+		} else {
+			// const _exported: Type; export {_exported as "name"};
+			newId := tx.Factory().NewUniqueNameEx("_exported", printer.AutoGenerateOptions{Flags: printer.GeneratedIdentifierFlagsOptimistic})
+			tx.state.getSymbolAccessibilityDiagnostic = func(_ printer.SymbolAccessibilityResult) *SymbolAccessibilityDiagnostic {
+				return &SymbolAccessibilityDiagnostic{
+					diagnosticMessage: diagnostics.Default_export_of_the_module_has_or_is_using_private_name_0,
+					errorNode:         input,
+				}
+			}
+			tx.tracker.PushErrorFallbackNode(input)
+			type_ := tx.ensureType(input, false)
+			varDecl := tx.Factory().NewVariableDeclaration(newId, nil, type_, nil)
+			tx.tracker.PopErrorFallbackNode()
+			var modList *ast.ModifierList
+			if tx.needsDeclare {
+				modList = tx.Factory().NewModifierList([]*ast.Node{tx.Factory().NewModifier(ast.KindDeclareKeyword)})
+			} else {
+				modList = tx.Factory().NewModifierList([]*ast.Node{})
+			}
+			statement := tx.Factory().NewVariableStatement(modList, tx.Factory().NewVariableDeclarationList(ast.NodeFlagsConst, tx.Factory().NewNodeList([]*ast.Node{varDecl})))
+
+			assignment := tx.Factory().NewExportDeclaration(nil, false, tx.Factory().NewNamedExports(tx.Factory().NewNodeList([]*ast.Node{tx.Factory().NewExportSpecifier(false, newId, name)})), nil, nil)
+			// Remove comments from the export declaration and copy them onto the synthetic _default declaration
+			tx.preserveJsDoc(statement, input)
+			tx.removeAllComments(assignment)
+			return tx.Factory().NewSyntaxList([]*ast.Node{statement, assignment})
+		}
 	case ast.KindExportAssignment, ast.KindJSExportAssignment:
 		if ast.IsSourceFile(input.Parent) {
 			tx.resultHasExternalModuleIndicator = true
diff --git a/internal/transformers/declarations/util.go b/internal/transformers/declarations/util.go
index e6d71f5697..dfd28f98ab 100644
--- a/internal/transformers/declarations/util.go
+++ b/internal/transformers/declarations/util.go
@@ -64,7 +64,8 @@ func hasInferredType(node *ast.Node) bool {
 		ast.KindPropertyAssignment,
 		ast.KindShorthandPropertyAssignment,
 		ast.KindJSDocParameterTag,
-		ast.KindJSDocPropertyTag:
+		ast.KindJSDocPropertyTag,
+		ast.KindCommonJSExport:
 		return true
 	default:
 		// assertType<never>(node); // !!!
diff --git a/testdata/baselines/reference/compiler/jsDeclarationExportDefaultAssignmentCrash.js b/testdata/baselines/reference/compiler/jsDeclarationExportDefaultAssignmentCrash.js
new file mode 100644
index 0000000000..0f64fde1de
--- /dev/null
+++ b/testdata/baselines/reference/compiler/jsDeclarationExportDefaultAssignmentCrash.js
@@ -0,0 +1,22 @@
+//// [tests/cases/compiler/jsDeclarationExportDefaultAssignmentCrash.ts] ////
+
+//// [index.js]
+exports.default = () => {
+    return 1234;
+}
+
+
+//// [index.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+export var default = () => {
+    return 1234;
+};
+exports.default = () => {
+    return 1234;
+};
+
+
+//// [index.d.ts]
+declare const _default: () => number;
+export default _default;
diff --git a/testdata/baselines/reference/compiler/jsDeclarationExportDefaultAssignmentCrash.symbols b/testdata/baselines/reference/compiler/jsDeclarationExportDefaultAssignmentCrash.symbols
new file mode 100644
index 0000000000..d6854289de
--- /dev/null
+++ b/testdata/baselines/reference/compiler/jsDeclarationExportDefaultAssignmentCrash.symbols
@@ -0,0 +1,11 @@
+//// [tests/cases/compiler/jsDeclarationExportDefaultAssignmentCrash.ts] ////
+
+=== index.js ===
+exports.default = () => {
+>exports.default : Symbol(default, Decl(index.js, 0, 0))
+>exports : Symbol("index", Decl(index.js, 0, 0))
+>default : Symbol(default, Decl(index.js, 0, 0))
+
+    return 1234;
+}
+
diff --git a/testdata/baselines/reference/compiler/jsDeclarationExportDefaultAssignmentCrash.types b/testdata/baselines/reference/compiler/jsDeclarationExportDefaultAssignmentCrash.types
new file mode 100644
index 0000000000..91e2e5fc03
--- /dev/null
+++ b/testdata/baselines/reference/compiler/jsDeclarationExportDefaultAssignmentCrash.types
@@ -0,0 +1,14 @@
+//// [tests/cases/compiler/jsDeclarationExportDefaultAssignmentCrash.ts] ////
+
+=== index.js ===
+exports.default = () => {
+>exports.default = () => {    return 1234;} : () => number
+>exports.default : () => number
+>exports : typeof import("index")
+>default : () => number
+>() => {    return 1234;} : () => number
+
+    return 1234;
+>1234 : 1234
+}
+
diff --git a/testdata/baselines/reference/submodule/compiler/jsExportAssignmentNonMutableLocation.js b/testdata/baselines/reference/submodule/compiler/jsExportAssignmentNonMutableLocation.js
index 635b4c6367..7b4d092edc 100644
--- a/testdata/baselines/reference/submodule/compiler/jsExportAssignmentNonMutableLocation.js
+++ b/testdata/baselines/reference/submodule/compiler/jsExportAssignmentNonMutableLocation.js
@@ -17,4 +17,4 @@ declare const _default: {
     customSymbol: symbol;
 };
 export = _default;
-export var customSymbol2 = Symbol("custom");
+export declare var customSymbol2: symbol;
diff --git a/testdata/baselines/reference/submodule/compiler/jsExportAssignmentNonMutableLocation.js.diff b/testdata/baselines/reference/submodule/compiler/jsExportAssignmentNonMutableLocation.js.diff
index 4094b52ae4..9d7a1df712 100644
--- a/testdata/baselines/reference/submodule/compiler/jsExportAssignmentNonMutableLocation.js.diff
+++ b/testdata/baselines/reference/submodule/compiler/jsExportAssignmentNonMutableLocation.js.diff
@@ -10,4 +10,4 @@
 +    customSymbol: symbol;
 +};
 +export = _default;
-+export var customSymbol2 = Symbol("custom");
\ No newline at end of file
++export declare var customSymbol2: symbol;
\ No newline at end of file
diff --git a/testdata/baselines/reference/submodule/compiler/modulePreserve4.js b/testdata/baselines/reference/submodule/compiler/modulePreserve4.js
index 1ec555552e..f9c42e3055 100644
--- a/testdata/baselines/reference/submodule/compiler/modulePreserve4.js
+++ b/testdata/baselines/reference/submodule/compiler/modulePreserve4.js
@@ -198,7 +198,7 @@ export {}; // Silly test harness
 
 //// [a.d.ts]
 export declare const x = 0;
-export var y = 0;
+export declare var y: number;
 //// [b.d.ts]
 declare const _default: number;
 export default _default;
@@ -217,8 +217,8 @@ export = _default;
 declare const _default: number;
 export default _default;
 //// [g.d.ts]
-export var default = 0;
-export {};
+declare const _default: number;
+export default _default;
 //// [main1.d.ts]
 export {};
 //// [main2.d.mts]
@@ -226,7 +226,6 @@ export {};
 //// [main3.d.cts]
 export {};
 //// [main4.d.cts]
-export var x = require("./g");
-export {};
+export declare var x: typeof import("./g");
 //// [dummy.d.ts]
 export {};
diff --git a/testdata/baselines/reference/submodule/compiler/modulePreserve4.js.diff b/testdata/baselines/reference/submodule/compiler/modulePreserve4.js.diff
index 84267b6dd2..2d93a76726 100644
--- a/testdata/baselines/reference/submodule/compiler/modulePreserve4.js.diff
+++ b/testdata/baselines/reference/submodule/compiler/modulePreserve4.js.diff
@@ -30,7 +30,7 @@
  //// [a.d.ts]
 -export const x: 0;
 +export declare const x = 0;
-+export var y = 0;
++export declare var y: number;
  //// [b.d.ts]
 -declare const _default: 0;
 +declare const _default: number;
@@ -50,18 +50,15 @@
  export default _default;
  //// [g.d.ts]
 -declare const _default: 0;
--export default _default;
-+export var default = 0;
-+export {};
++declare const _default: number;
+ export default _default;
  //// [main1.d.ts]
  export {};
- //// [main2.d.mts]
 @@= skipped -15, +15 lines =@@
  //// [main3.d.cts]
  export {};
  //// [main4.d.cts]
 -export const x: typeof import("./g");
-+export var x = require("./g");
-+export {};
++export declare var x: typeof import("./g");
  //// [dummy.d.ts]
  export {};
\ No newline at end of file
diff --git a/testdata/baselines/reference/submodule/conformance/assignmentToVoidZero1.js b/testdata/baselines/reference/submodule/conformance/assignmentToVoidZero1.js
index 8a0b1128f3..54f30a42d6 100644
--- a/testdata/baselines/reference/submodule/conformance/assignmentToVoidZero1.js
+++ b/testdata/baselines/reference/submodule/conformance/assignmentToVoidZero1.js
@@ -21,7 +21,6 @@ exports.y = 2;
 
 
 //// [assignmentToVoidZero1.d.ts]
-export var y = exports.x = void 0;
-export var x = 1;
-export var y = 2;
-export {};
+export declare var y: undefined;
+export declare var x: number;
+export declare var y: undefined;
diff --git a/testdata/baselines/reference/submodule/conformance/assignmentToVoidZero1.js.diff b/testdata/baselines/reference/submodule/conformance/assignmentToVoidZero1.js.diff
index 18d553cbdf..714b31fe2a 100644
--- a/testdata/baselines/reference/submodule/conformance/assignmentToVoidZero1.js.diff
+++ b/testdata/baselines/reference/submodule/conformance/assignmentToVoidZero1.js.diff
@@ -19,7 +19,6 @@
  //// [assignmentToVoidZero1.d.ts]
 -export const x: 1;
 -export const y: 2;
-+export var y = exports.x = void 0;
-+export var x = 1;
-+export var y = 2;
-+export {};
\ No newline at end of file
++export declare var y: undefined;
++export declare var x: number;
++export declare var y: undefined;
\ No newline at end of file
diff --git a/testdata/baselines/reference/submodule/conformance/assignmentToVoidZero2.js b/testdata/baselines/reference/submodule/conformance/assignmentToVoidZero2.js
index e79804a05e..9b3221fcfd 100644
--- a/testdata/baselines/reference/submodule/conformance/assignmentToVoidZero2.js
+++ b/testdata/baselines/reference/submodule/conformance/assignmentToVoidZero2.js
@@ -45,14 +45,13 @@ assignmentToVoidZero2_1.j + assignmentToVoidZero2_1.k;
 
 
 //// [assignmentToVoidZero2.d.ts]
-export var j = 1;
-export var k = void 0;
+export declare var j: number;
+export declare var k: undefined;
 declare namespace o {
     var x: number;
 }
 declare namespace o {
     var y: any;
 }
-export {};
 //// [importer.d.ts]
 export {};
diff --git a/testdata/baselines/reference/submodule/conformance/assignmentToVoidZero2.js.diff b/testdata/baselines/reference/submodule/conformance/assignmentToVoidZero2.js.diff
index a08ceb9494..25462c35e7 100644
--- a/testdata/baselines/reference/submodule/conformance/assignmentToVoidZero2.js.diff
+++ b/testdata/baselines/reference/submodule/conformance/assignmentToVoidZero2.js.diff
@@ -23,14 +23,13 @@
 
  //// [assignmentToVoidZero2.d.ts]
 -export const j: 1;
-+export var j = 1;
-+export var k = void 0;
++export declare var j: number;
++export declare var k: undefined;
 +declare namespace o {
 +    var x: number;
 +}
 +declare namespace o {
 +    var y: any;
 +}
-+export {};
  //// [importer.d.ts]
  export {};
\ No newline at end of file
diff --git a/testdata/baselines/reference/submodule/conformance/commonJSAliasedExport.js b/testdata/baselines/reference/submodule/conformance/commonJSAliasedExport.js
index 239db68d84..e612aa9e18 100644
--- a/testdata/baselines/reference/submodule/conformance/commonJSAliasedExport.js
+++ b/testdata/baselines/reference/submodule/conformance/commonJSAliasedExport.js
@@ -36,7 +36,8 @@ var diddy = funky(1);
 
 
 //// [commonJSAliasedExport.d.ts]
+declare function funky(declaration: any): boolean;
 export = donkey;
-export var funky = funky;
+export declare var funky: typeof funky;
 //// [bug43713.d.ts]
 export {};
diff --git a/testdata/baselines/reference/submodule/conformance/commonJSAliasedExport.js.diff b/testdata/baselines/reference/submodule/conformance/commonJSAliasedExport.js.diff
index 3d91b41bc0..f658a2e9e7 100644
--- a/testdata/baselines/reference/submodule/conformance/commonJSAliasedExport.js.diff
+++ b/testdata/baselines/reference/submodule/conformance/commonJSAliasedExport.js.diff
@@ -16,15 +16,17 @@
  module.exports.funky = funky;
  //// [bug43713.js]
  const { funky } = require('./commonJSAliasedExport');
-@@= skipped -15, +19 lines =@@
+@@= skipped -14, +18 lines =@@
+
 
  //// [commonJSAliasedExport.d.ts]
- export = donkey;
+-export = donkey;
 -declare function donkey(ast: any): any;
 -declare namespace donkey {
 -    export { funky };
 -}
--declare function funky(declaration: any): boolean;
-+export var funky = funky;
+ declare function funky(declaration: any): boolean;
++export = donkey;
++export declare var funky: typeof funky;
  //// [bug43713.d.ts]
  export {};
\ No newline at end of file
diff --git a/testdata/baselines/reference/submodule/conformance/commonJSImportClassTypeReference.js b/testdata/baselines/reference/submodule/conformance/commonJSImportClassTypeReference.js
index eb041a90a1..6d25b48359 100644
--- a/testdata/baselines/reference/submodule/conformance/commonJSImportClassTypeReference.js
+++ b/testdata/baselines/reference/submodule/conformance/commonJSImportClassTypeReference.js
@@ -36,7 +36,9 @@ function f(k) {
 
 
 //// [mod1.d.ts]
-export var K = K;
-export {};
+declare class K {
+    values(): K;
+}
+export declare var K: typeof K;
 //// [main.d.ts]
 export {};
diff --git a/testdata/baselines/reference/submodule/conformance/commonJSImportClassTypeReference.js.diff b/testdata/baselines/reference/submodule/conformance/commonJSImportClassTypeReference.js.diff
index 9c2c311535..b8983fb6eb 100644
--- a/testdata/baselines/reference/submodule/conformance/commonJSImportClassTypeReference.js.diff
+++ b/testdata/baselines/reference/submodule/conformance/commonJSImportClassTypeReference.js.diff
@@ -19,9 +19,9 @@
 
  //// [mod1.d.ts]
 -export class K {
--    values(): K;
--}
-+export var K = K;
-+export {};
++declare class K {
+     values(): K;
+ }
++export declare var K: typeof K;
  //// [main.d.ts]
  export {};
\ No newline at end of file
diff --git a/testdata/baselines/reference/submodule/conformance/commonJSImportExportedClassExpression.js b/testdata/baselines/reference/submodule/conformance/commonJSImportExportedClassExpression.js
index da4ecfbfd1..60789d061e 100644
--- a/testdata/baselines/reference/submodule/conformance/commonJSImportExportedClassExpression.js
+++ b/testdata/baselines/reference/submodule/conformance/commonJSImportExportedClassExpression.js
@@ -35,9 +35,10 @@ function f(k) {
 
 
 //// [mod1.d.ts]
-export var K = class K {
-    values(): void;
+export declare var K: {
+    new (): {
+        values(): void;
+    };
 };
-export {};
 //// [main.d.ts]
 export {};
diff --git a/testdata/baselines/reference/submodule/conformance/commonJSImportExportedClassExpression.js.diff b/testdata/baselines/reference/submodule/conformance/commonJSImportExportedClassExpression.js.diff
index 259e8b473a..eedc85ac50 100644
--- a/testdata/baselines/reference/submodule/conformance/commonJSImportExportedClassExpression.js.diff
+++ b/testdata/baselines/reference/submodule/conformance/commonJSImportExportedClassExpression.js.diff
@@ -17,10 +17,12 @@
 
  //// [mod1.d.ts]
 -export class K {
-+export var K = class K {
-     values(): void;
+-    values(): void;
 -}
++export declare var K: {
++    new (): {
++        values(): void;
++    };
 +};
-+export {};
  //// [main.d.ts]
  export {};
\ No newline at end of file
diff --git a/testdata/baselines/reference/submodule/conformance/commonJSImportNestedClassTypeReference.js b/testdata/baselines/reference/submodule/conformance/commonJSImportNestedClassTypeReference.js
index 39c2df78a4..bd6dfdc330 100644
--- a/testdata/baselines/reference/submodule/conformance/commonJSImportNestedClassTypeReference.js
+++ b/testdata/baselines/reference/submodule/conformance/commonJSImportNestedClassTypeReference.js
@@ -45,7 +45,10 @@ declare namespace NS {
         };
     };
 }
-export var K = NS.K;
-export {};
+export declare var K: {
+    new (): {
+        values(): /*elided*/ any;
+    };
+};
 //// [main.d.ts]
 export {};
diff --git a/testdata/baselines/reference/submodule/conformance/commonJSImportNestedClassTypeReference.js.diff b/testdata/baselines/reference/submodule/conformance/commonJSImportNestedClassTypeReference.js.diff
index 7dcf48b386..263c8c011e 100644
--- a/testdata/baselines/reference/submodule/conformance/commonJSImportNestedClassTypeReference.js.diff
+++ b/testdata/baselines/reference/submodule/conformance/commonJSImportNestedClassTypeReference.js.diff
@@ -20,17 +20,14 @@
 
  //// [mod1.d.ts]
 -export var K: {
--    new (): {
--        values(): /*elided*/ any;
 +declare namespace NS {
 +    var K: {
 +        new (): {
 +            values(): /*elided*/ any;
 +        };
-     };
--};
++    };
 +}
-+export var K = NS.K;
-+export {};
- //// [main.d.ts]
- export {};
\ No newline at end of file
++export declare var K: {
+     new (): {
+         values(): /*elided*/ any;
+     };
\ No newline at end of file
diff --git a/testdata/baselines/reference/submodule/conformance/jsDeclarationsClassExtendsVisibility.js b/testdata/baselines/reference/submodule/conformance/jsDeclarationsClassExtendsVisibility.js
index 873919cc36..b8868c1a18 100644
--- a/testdata/baselines/reference/submodule/conformance/jsDeclarationsClassExtendsVisibility.js
+++ b/testdata/baselines/reference/submodule/conformance/jsDeclarationsClassExtendsVisibility.js
@@ -38,4 +38,7 @@ module.exports.Strings = Strings;
 export = Bar;
 //// [cls.d.ts]
 export = Foo;
-export var Strings = Strings;
+export declare var Strings: {
+    a: string;
+    b: string;
+};
diff --git a/testdata/baselines/reference/submodule/conformance/jsDeclarationsClassExtendsVisibility.js.diff b/testdata/baselines/reference/submodule/conformance/jsDeclarationsClassExtendsVisibility.js.diff
index 8d3685964a..bb250feeab 100644
--- a/testdata/baselines/reference/submodule/conformance/jsDeclarationsClassExtendsVisibility.js.diff
+++ b/testdata/baselines/reference/submodule/conformance/jsDeclarationsClassExtendsVisibility.js.diff
@@ -38,4 +38,7 @@
 -    let a: string;
 -    let b: string;
 -}
-+export var Strings = Strings;
\ No newline at end of file
++export declare var Strings: {
++    a: string;
++    b: string;
++};
\ No newline at end of file
diff --git a/testdata/baselines/reference/submodule/conformance/jsDeclarationsClassStatic.js b/testdata/baselines/reference/submodule/conformance/jsDeclarationsClassStatic.js
index 72c30e4c2a..22db15c153 100644
--- a/testdata/baselines/reference/submodule/conformance/jsDeclarationsClassStatic.js
+++ b/testdata/baselines/reference/submodule/conformance/jsDeclarationsClassStatic.js
@@ -56,7 +56,10 @@ declare namespace Handler {
     var statische: () => void;
 }
 export = Handler;
-export var Strings = Strings;
+export declare var Strings: {
+    a: string;
+    b: string;
+};
 export type HandlerOptions = {
     name: String;
 };
diff --git a/testdata/baselines/reference/submodule/conformance/jsDeclarationsClassStatic.js.diff b/testdata/baselines/reference/submodule/conformance/jsDeclarationsClassStatic.js.diff
index 17b3390c8f..38da037666 100644
--- a/testdata/baselines/reference/submodule/conformance/jsDeclarationsClassStatic.js.diff
+++ b/testdata/baselines/reference/submodule/conformance/jsDeclarationsClassStatic.js.diff
@@ -41,13 +41,17 @@
 -     * Should be able to export a type alias at the same time.
 -     */
 -    name: string;
+-};
 +    var statische: () => void;
 +}
 +export = Handler;
-+export var Strings = Strings;
++export declare var Strings: {
++    a: string;
++    b: string;
++};
 +export type HandlerOptions = {
 +    name: String;
- };
++};
 +/**
 + * @typedef {Object} HandlerOptions
 + * @property {String} name
diff --git a/testdata/baselines/reference/submodule/conformance/jsDeclarationsCrossfileMerge.js b/testdata/baselines/reference/submodule/conformance/jsDeclarationsCrossfileMerge.js
index 43d7d8a23b..c7dda4b311 100644
--- a/testdata/baselines/reference/submodule/conformance/jsDeclarationsCrossfileMerge.js
+++ b/testdata/baselines/reference/submodule/conformance/jsDeclarationsCrossfileMerge.js
@@ -34,4 +34,4 @@ export default validate;
 declare const m: typeof m;
 declare const _default: typeof m.default;
 export = _default;
-export var memberName = "thing";
+export declare var memberName: string;
diff --git a/testdata/baselines/reference/submodule/conformance/jsDeclarationsCrossfileMerge.js.diff b/testdata/baselines/reference/submodule/conformance/jsDeclarationsCrossfileMerge.js.diff
index 3c0477cb71..909afdba18 100644
--- a/testdata/baselines/reference/submodule/conformance/jsDeclarationsCrossfileMerge.js.diff
+++ b/testdata/baselines/reference/submodule/conformance/jsDeclarationsCrossfileMerge.js.diff
@@ -28,4 +28,4 @@
 +declare const m: typeof m;
 +declare const _default: typeof m.default;
 +export = _default;
-+export var memberName = "thing";
\ No newline at end of file
++export declare var memberName: string;
\ No newline at end of file
diff --git a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedClassExpressionAnonymousWithSub.js b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedClassExpressionAnonymousWithSub.js
index feff514416..3a002970dd 100644
--- a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedClassExpressionAnonymousWithSub.js
+++ b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedClassExpressionAnonymousWithSub.js
@@ -46,6 +46,10 @@ declare const _default: {
     };
 };
 export = _default;
-export var Sub = class {
-    constructor();
+export declare var Sub: {
+    new (): {
+        instance: {
+            t: number;
+        };
+    };
 };
diff --git a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedClassExpressionAnonymousWithSub.js.diff b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedClassExpressionAnonymousWithSub.js.diff
index b8d1314888..635641bdd8 100644
--- a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedClassExpressionAnonymousWithSub.js.diff
+++ b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedClassExpressionAnonymousWithSub.js.diff
@@ -45,6 +45,10 @@
 +    };
 +};
 +export = _default;
-+export var Sub = class {
-+    constructor();
++export declare var Sub: {
++    new (): {
++        instance: {
++            t: number;
++        };
++    };
 +};
\ No newline at end of file
diff --git a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedClassExpressionShadowing.js b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedClassExpressionShadowing.js
index 0d111728d1..0e6b5aa563 100644
--- a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedClassExpressionShadowing.js
+++ b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedClassExpressionShadowing.js
@@ -51,4 +51,4 @@ declare const _default: {
     };
 };
 export = _default;
-export var Another = Q;
+export declare var Another: typeof Q;
diff --git a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedClassExpressionShadowing.js.diff b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedClassExpressionShadowing.js.diff
index 79b32ca0bf..426129727c 100644
--- a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedClassExpressionShadowing.js.diff
+++ b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedClassExpressionShadowing.js.diff
@@ -52,4 +52,4 @@
 +    };
 +};
 +export = _default;
-+export var Another = Q;
\ No newline at end of file
++export declare var Another: typeof Q;
\ No newline at end of file
diff --git a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedClassInstance3.js b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedClassInstance3.js
index b0cf369223..0d20499ae7 100644
--- a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedClassInstance3.js
+++ b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedClassInstance3.js
@@ -30,4 +30,4 @@ declare class Foo {
 }
 declare const _default: Foo;
 export = _default;
-export var additional = 20;
+export declare var additional: number;
diff --git a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedClassInstance3.js.diff b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedClassInstance3.js.diff
index b674f89330..f60203ee9d 100644
--- a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedClassInstance3.js.diff
+++ b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedClassInstance3.js.diff
@@ -34,4 +34,4 @@
 +}
 +declare const _default: Foo;
 +export = _default;
-+export var additional = 20;
\ No newline at end of file
++export declare var additional: number;
\ No newline at end of file
diff --git a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedConstructorFunction.js b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedConstructorFunction.js
index f73905bca5..50c7df5365 100644
--- a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedConstructorFunction.js
+++ b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedConstructorFunction.js
@@ -29,21 +29,4 @@ module.exports.MyClass.prototype = {
 
 
 //// [jsDeclarationsExportAssignedConstructorFunction.d.ts]
-/** @constructor */
-export var MyClass = function ();;
-export {};
-
-
-//// [DtsFileErrors]
-
-
-out/jsDeclarationsExportAssignedConstructorFunction.d.ts(2,33): error TS1005: '{' expected.
-
-
-==== out/jsDeclarationsExportAssignedConstructorFunction.d.ts (1 errors) ====
-    /** @constructor */
-    export var MyClass = function ();;
-                                    ~
-!!! error TS1005: '{' expected.
-    export {};
-    
\ No newline at end of file
+export declare var MyClass: () => void;
diff --git a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedConstructorFunction.js.diff b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedConstructorFunction.js.diff
index 089c0e854d..a1e3ca15d5 100644
--- a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedConstructorFunction.js.diff
+++ b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedConstructorFunction.js.diff
@@ -20,21 +20,4 @@
 -export class MyClass {
 -    a: () => void;
 -}
-+/** @constructor */
-+export var MyClass = function ();;
-+export {};
-+
-+
-+//// [DtsFileErrors]
-+
-+
-+out/jsDeclarationsExportAssignedConstructorFunction.d.ts(2,33): error TS1005: '{' expected.
-+
-+
-+==== out/jsDeclarationsExportAssignedConstructorFunction.d.ts (1 errors) ====
-+    /** @constructor */
-+    export var MyClass = function ();;
-+                                    ~
-+!!! error TS1005: '{' expected.
-+    export {};
-+    
\ No newline at end of file
++export declare var MyClass: () => void;
\ No newline at end of file
diff --git a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedConstructorFunctionWithSub.js b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedConstructorFunctionWithSub.js
index f1fcca9856..329fb95300 100644
--- a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedConstructorFunctionWithSub.js
+++ b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedConstructorFunctionWithSub.js
@@ -40,4 +40,4 @@ module.exports.Sub.prototype = {};
 //// [jsDeclarationsExportAssignedConstructorFunctionWithSub.d.ts]
 declare const _default: (p: any) => void;
 export = _default;
-export var Sub = function ();;
+export declare var Sub: () => void;
diff --git a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedConstructorFunctionWithSub.js.diff b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedConstructorFunctionWithSub.js.diff
index 8724348065..552b990ef4 100644
--- a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedConstructorFunctionWithSub.js.diff
+++ b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignedConstructorFunctionWithSub.js.diff
@@ -30,4 +30,4 @@
 +//// [jsDeclarationsExportAssignedConstructorFunctionWithSub.d.ts]
 +declare const _default: (p: any) => void;
 +export = _default;
-+export var Sub = function ();;
\ No newline at end of file
++export declare var Sub: () => void;
\ No newline at end of file
diff --git a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignmentExpressionPlusSecondary.js b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignmentExpressionPlusSecondary.js
index 1fafdc93b4..d364596b63 100644
--- a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignmentExpressionPlusSecondary.js
+++ b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignmentExpressionPlusSecondary.js
@@ -49,4 +49,7 @@ declare const _default: {
     };
 };
 export = _default;
-export var Strings = Strings;
+export declare var Strings: {
+    a: string;
+    b: string;
+};
diff --git a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignmentExpressionPlusSecondary.js.diff b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignmentExpressionPlusSecondary.js.diff
index 65c013a360..b1e559719e 100644
--- a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignmentExpressionPlusSecondary.js.diff
+++ b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportAssignmentExpressionPlusSecondary.js.diff
@@ -46,4 +46,7 @@
 +    };
 +};
 +export = _default;
-+export var Strings = Strings;
\ No newline at end of file
++export declare var Strings: {
++    a: string;
++    b: string;
++};
\ No newline at end of file
diff --git a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportForms.js b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportForms.js
index 58e1e4b0ff..93fb7301b1 100644
--- a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportForms.js
+++ b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportForms.js
@@ -195,11 +195,11 @@ export = _default;
 //// [cjs2.d.ts]
 export = ns;
 //// [cjs3.d.ts]
-export var ns = ns;
-export {};
+declare const ns: typeof ns;
+export declare var ns: typeof ns;
 //// [cjs4.d.ts]
-export var names = ns;
-export {};
+declare const ns: typeof ns;
+export declare var names: typeof ns;
 //// [includeAll.d.ts]
 import "./cjs4";
 import "./cjs3";
@@ -218,9 +218,12 @@ import "./bar2";
 
 out/cjs.d.ts(1,15): error TS2502: 'ns' is referenced directly or indirectly in its own type annotation.
 out/cjs2.d.ts(1,10): error TS2304: Cannot find name 'ns'.
-out/cjs3.d.ts(1,17): error TS1039: Initializers are not allowed in ambient contexts.
-out/cjs4.d.ts(1,20): error TS1039: Initializers are not allowed in ambient contexts.
-out/cjs4.d.ts(1,20): error TS2304: Cannot find name 'ns'.
+out/cjs3.d.ts(1,15): error TS2395: Individual declarations in merged declaration 'ns' must be all exported or all local.
+out/cjs3.d.ts(1,15): error TS2451: Cannot redeclare block-scoped variable 'ns'.
+out/cjs3.d.ts(2,20): error TS2395: Individual declarations in merged declaration 'ns' must be all exported or all local.
+out/cjs3.d.ts(2,20): error TS2451: Cannot redeclare block-scoped variable 'ns'.
+out/cjs3.d.ts(2,20): error TS2502: 'ns' is referenced directly or indirectly in its own type annotation.
+out/cjs4.d.ts(1,15): error TS2502: 'ns' is referenced directly or indirectly in its own type annotation.
 
 
 ==== out/cls.d.ts (0 errors) ====
@@ -267,19 +270,25 @@ out/cjs4.d.ts(1,20): error TS2304: Cannot find name 'ns'.
              ~~
 !!! error TS2304: Cannot find name 'ns'.
     
-==== out/cjs3.d.ts (1 errors) ====
-    export var ns = ns;
-                    ~~
-!!! error TS1039: Initializers are not allowed in ambient contexts.
-    export {};
-    
-==== out/cjs4.d.ts (2 errors) ====
-    export var names = ns;
+==== out/cjs3.d.ts (5 errors) ====
+    declare const ns: typeof ns;
+                  ~~
+!!! error TS2395: Individual declarations in merged declaration 'ns' must be all exported or all local.
+                  ~~
+!!! error TS2451: Cannot redeclare block-scoped variable 'ns'.
+    export declare var ns: typeof ns;
                        ~~
-!!! error TS1039: Initializers are not allowed in ambient contexts.
+!!! error TS2395: Individual declarations in merged declaration 'ns' must be all exported or all local.
                        ~~
-!!! error TS2304: Cannot find name 'ns'.
-    export {};
+!!! error TS2451: Cannot redeclare block-scoped variable 'ns'.
+                       ~~
+!!! error TS2502: 'ns' is referenced directly or indirectly in its own type annotation.
+    
+==== out/cjs4.d.ts (1 errors) ====
+    declare const ns: typeof ns;
+                  ~~
+!!! error TS2502: 'ns' is referenced directly or indirectly in its own type annotation.
+    export declare var names: typeof ns;
     
 ==== out/includeAll.d.ts (0 errors) ====
     import "./cjs4";
diff --git a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportForms.js.diff b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportForms.js.diff
index 0d7c673b3d..b1bcde6b98 100644
--- a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportForms.js.diff
+++ b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportForms.js.diff
@@ -93,13 +93,13 @@
  //// [cjs3.d.ts]
 -export { ns };
 -import ns = require("./cls");
-+export var ns = ns;
-+export {};
++declare const ns: typeof ns;
++export declare var ns: typeof ns;
  //// [cjs4.d.ts]
 -export { ns as names };
 -import ns = require("./cls");
-+export var names = ns;
-+export {};
++declare const ns: typeof ns;
++export declare var names: typeof ns;
  //// [includeAll.d.ts]
 -export {};
 +import "./cjs4";
@@ -119,9 +119,12 @@
 +
 +out/cjs.d.ts(1,15): error TS2502: 'ns' is referenced directly or indirectly in its own type annotation.
 +out/cjs2.d.ts(1,10): error TS2304: Cannot find name 'ns'.
-+out/cjs3.d.ts(1,17): error TS1039: Initializers are not allowed in ambient contexts.
-+out/cjs4.d.ts(1,20): error TS1039: Initializers are not allowed in ambient contexts.
-+out/cjs4.d.ts(1,20): error TS2304: Cannot find name 'ns'.
++out/cjs3.d.ts(1,15): error TS2395: Individual declarations in merged declaration 'ns' must be all exported or all local.
++out/cjs3.d.ts(1,15): error TS2451: Cannot redeclare block-scoped variable 'ns'.
++out/cjs3.d.ts(2,20): error TS2395: Individual declarations in merged declaration 'ns' must be all exported or all local.
++out/cjs3.d.ts(2,20): error TS2451: Cannot redeclare block-scoped variable 'ns'.
++out/cjs3.d.ts(2,20): error TS2502: 'ns' is referenced directly or indirectly in its own type annotation.
++out/cjs4.d.ts(1,15): error TS2502: 'ns' is referenced directly or indirectly in its own type annotation.
 +
 +
 +==== out/cls.d.ts (0 errors) ====
@@ -168,19 +171,25 @@
 +             ~~
 +!!! error TS2304: Cannot find name 'ns'.
 +    
-+==== out/cjs3.d.ts (1 errors) ====
-+    export var ns = ns;
-+                    ~~
-+!!! error TS1039: Initializers are not allowed in ambient contexts.
-+    export {};
-+    
-+==== out/cjs4.d.ts (2 errors) ====
-+    export var names = ns;
++==== out/cjs3.d.ts (5 errors) ====
++    declare const ns: typeof ns;
++                  ~~
++!!! error TS2395: Individual declarations in merged declaration 'ns' must be all exported or all local.
++                  ~~
++!!! error TS2451: Cannot redeclare block-scoped variable 'ns'.
++    export declare var ns: typeof ns;
 +                       ~~
-+!!! error TS1039: Initializers are not allowed in ambient contexts.
++!!! error TS2395: Individual declarations in merged declaration 'ns' must be all exported or all local.
 +                       ~~
-+!!! error TS2304: Cannot find name 'ns'.
-+    export {};
++!!! error TS2451: Cannot redeclare block-scoped variable 'ns'.
++                       ~~
++!!! error TS2502: 'ns' is referenced directly or indirectly in its own type annotation.
++    
++==== out/cjs4.d.ts (1 errors) ====
++    declare const ns: typeof ns;
++                  ~~
++!!! error TS2502: 'ns' is referenced directly or indirectly in its own type annotation.
++    export declare var names: typeof ns;
 +    
 +==== out/includeAll.d.ts (0 errors) ====
 +    import "./cjs4";
diff --git a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportSubAssignments.js b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportSubAssignments.js
index 0dd0b9d043..eded4b1dac 100644
--- a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportSubAssignments.js
+++ b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportSubAssignments.js
@@ -26,4 +26,7 @@ module.exports.Strings = Strings;
 
 //// [cls.d.ts]
 export = Foo;
-export var Strings = Strings;
+export declare var Strings: {
+    a: string;
+    b: string;
+};
diff --git a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportSubAssignments.js.diff b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportSubAssignments.js.diff
index 94c7fd4dbd..169cc9bb8a 100644
--- a/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportSubAssignments.js.diff
+++ b/testdata/baselines/reference/submodule/conformance/jsDeclarationsExportSubAssignments.js.diff
@@ -29,4 +29,7 @@
 -    let a: string;
 -    let b: string;
 -}
-+export var Strings = Strings;
\ No newline at end of file
++export declare var Strings: {
++    a: string;
++    b: string;
++};
\ No newline at end of file
diff --git a/testdata/baselines/reference/submodule/conformance/jsDeclarationsFunctionsCjs.js b/testdata/baselines/reference/submodule/conformance/jsDeclarationsFunctionsCjs.js
index ae049969e2..e8f0949e96 100644
--- a/testdata/baselines/reference/submodule/conformance/jsDeclarationsFunctionsCjs.js
+++ b/testdata/baselines/reference/submodule/conformance/jsDeclarationsFunctionsCjs.js
@@ -145,31 +145,33 @@ module.exports.j = function j() { };
 
 
 //// [index.d.ts]
-export var a = function a();;
-export var b = function b();;
-export var c = function c();;
+export declare var a: () => void;
+export declare var b: () => void;
+export declare var c: () => void;
+export declare var d: (a: any, b: any) => any;
+export declare var e: (a: any, b: any) => any;
+export declare var f: (a: any) => any;
 /**
- * @param {number} a
- * @param {number} b
- * @return {string}
- */
-export var d = function d(a, b);;
-/**
- * @template T,U
- * @param {T} a
- * @param {U} b
- * @return {T & U}
+ * @param {{x: string}} a
+ * @param {{y: typeof module.exports.b}} b
  */
-export var e = function e(a, b);;
+declare function g(a: {
+    x: string;
+}, b: {
+    y: typeof module.exports.b;
+}): any;
+export declare var g: typeof g;
 /**
- * @template T
- * @param {T} a
+ * @param {{x: string}} a
+ * @param {{y: typeof module.exports.b}} b
  */
-export var f = function f(a);;
-export var g = g;
-export var h = hh;
-export var i = function i();;
-export var ii = module.exports.i;
-export var jj = module.exports.j;
-export var j = function j();;
-export {};
+declare function hh(a: {
+    x: string;
+}, b: {
+    y: typeof module.exports.b;
+}): any;
+export declare var h: typeof hh;
+export declare var i: () => void;
+export declare var ii: () => void;
+export declare var jj: () => void;
+export declare var j: () => void;
diff --git a/testdata/baselines/reference/submodule/conformance/jsDeclarationsFunctionsCjs.js.diff b/testdata/baselines/reference/submodule/conformance/jsDeclarationsFunctionsCjs.js.diff
index 6c5287fed0..014da86514 100644
--- a/testdata/baselines/reference/submodule/conformance/jsDeclarationsFunctionsCjs.js.diff
+++ b/testdata/baselines/reference/submodule/conformance/jsDeclarationsFunctionsCjs.js.diff
@@ -105,56 +105,45 @@
 -export function j(): void;
 -declare class Cls {
 -}
--/**
-- * @param {{x: string}} a
-- * @param {{y: typeof module.exports.b}} b
-- */
++export declare var a: () => void;
++export declare var b: () => void;
++export declare var c: () => void;
++export declare var d: (a: any, b: any) => any;
++export declare var e: (a: any, b: any) => any;
++export declare var f: (a: any) => any;
+ /**
+  * @param {{x: string}} a
+  * @param {{y: typeof module.exports.b}} b
+  */
 -export function g(a: {
--    x: string;
--}, b: {
++declare function g(a: {
+     x: string;
+ }, b: {
 -    y: {
 -        (): void;
 -        cat: string;
 -    };
 -}): void;
--/**
-- * @param {{x: string}} a
-- * @param {{y: typeof module.exports.b}} b
-- */
--declare function hh(a: {
--    x: string;
--}, b: {
++    y: typeof module.exports.b;
++}): any;
++export declare var g: typeof g;
+ /**
+  * @param {{x: string}} a
+  * @param {{y: typeof module.exports.b}} b
+@@= skipped -48, +38 lines =@@
+ declare function hh(a: {
+     x: string;
+ }, b: {
 -    y: {
 -        (): void;
 -        cat: string;
 -    };
 -}): void;
 -export { hh as h, i as ii, j as jj };
-+export var a = function a();;
-+export var b = function b();;
-+export var c = function c();;
-+/**
-+ * @param {number} a
-+ * @param {number} b
-+ * @return {string}
-+ */
-+export var d = function d(a, b);;
-+/**
-+ * @template T,U
-+ * @param {T} a
-+ * @param {U} b
-+ * @return {T & U}
-+ */
-+export var e = function e(a, b);;
-+/**
-+ * @template T
-+ * @param {T} a
-+ */
-+export var f = function f(a);;
-+export var g = g;
-+export var h = hh;
-+export var i = function i();;
-+export var ii = module.exports.i;
-+export var jj = module.exports.j;
-+export var j = function j();;
-+export {};
\ No newline at end of file
++    y: typeof module.exports.b;
++}): any;
++export declare var h: typeof hh;
++export declare var i: () => void;
++export declare var ii: () => void;
++export declare var jj: () => void;
++export declare var j: () => void;
\ No newline at end of file
diff --git a/testdata/baselines/reference/submodule/conformance/jsDeclarationsImportAliasExposedWithinNamespaceCjs.js b/testdata/baselines/reference/submodule/conformance/jsDeclarationsImportAliasExposedWithinNamespaceCjs.js
index 55d6a0df23..ba40b630ab 100644
--- a/testdata/baselines/reference/submodule/conformance/jsDeclarationsImportAliasExposedWithinNamespaceCjs.js
+++ b/testdata/baselines/reference/submodule/conformance/jsDeclarationsImportAliasExposedWithinNamespaceCjs.js
@@ -60,14 +60,7 @@ export type myTypes = {
     prop2: string;
 };
 export type myTypes = myTypes.typeB | Function;
-/** @typedef {string|RegExp|Array<string|RegExp>} myTypes.typeA */
-/**
- * @typedef myTypes.typeB
- * @property {myTypes.typeA}    prop1 - Prop 1.
- * @property {string}           prop2 - Prop 2.
- */
-/** @typedef {myTypes.typeB|Function} myTypes.typeC */
-export var myTypes = myTypes;
+export declare var myTypes: any;
 //// [file2.d.ts]
 export type testFnTypes = boolean | myTypes.typeC;
 /** @typedef {boolean|myTypes.typeC} testFnTypes.input */
diff --git a/testdata/baselines/reference/submodule/conformance/jsDeclarationsImportAliasExposedWithinNamespaceCjs.js.diff b/testdata/baselines/reference/submodule/conformance/jsDeclarationsImportAliasExposedWithinNamespaceCjs.js.diff
index ff18b56816..bf77c50f99 100644
--- a/testdata/baselines/reference/submodule/conformance/jsDeclarationsImportAliasExposedWithinNamespaceCjs.js.diff
+++ b/testdata/baselines/reference/submodule/conformance/jsDeclarationsImportAliasExposedWithinNamespaceCjs.js.diff
@@ -4,24 +4,18 @@
 
 
  //// [file.d.ts]
-+export type myTypes = string | RegExp | Array<string | RegExp>;
-+export type myTypes = {
-+    prop1: myTypes.typeA;
-+    prop2: string;
-+};
-+export type myTypes = myTypes.typeB | Function;
-+/** @typedef {string|RegExp|Array<string|RegExp>} myTypes.typeA */
- /**
+-/**
 - * @namespace myTypes
 - * @global
 - * @type {Object<string,*>}
-+ * @typedef myTypes.typeB
-+ * @property {myTypes.typeA}    prop1 - Prop 1.
-+ * @property {string}           prop2 - Prop 2.
-  */
+- */
 -export const myTypes: {
 -    [x: string]: any;
--};
++export type myTypes = string | RegExp | Array<string | RegExp>;
++export type myTypes = {
++    prop1: myTypes.typeA;
++    prop2: string;
+ };
 -export namespace myTypes {
 -    type typeA = string | RegExp | Array<string | RegExp>;
 -    type typeB = {
@@ -36,14 +30,14 @@
 -    };
 -    type typeC = myTypes.typeB | Function;
 -}
-+/** @typedef {myTypes.typeB|Function} myTypes.typeC */
-+export var myTypes = myTypes;
++export type myTypes = myTypes.typeB | Function;
++export declare var myTypes: any;
  //// [file2.d.ts]
 +export type testFnTypes = boolean | myTypes.typeC;
  /** @typedef {boolean|myTypes.typeC} testFnTypes.input */
  /**
   * @function testFn
-@@= skipped -30, +23 lines =@@
+@@= skipped -30, +16 lines =@@
   * @param {testFnTypes.input} input - Input.
   * @returns {number|null} Result.
   */
diff --git a/testdata/baselines/reference/submodule/conformance/jsDeclarationsTypeReferences3.js b/testdata/baselines/reference/submodule/conformance/jsDeclarationsTypeReferences3.js
index c92bd9bc18..0469b5358c 100644
--- a/testdata/baselines/reference/submodule/conformance/jsDeclarationsTypeReferences3.js
+++ b/testdata/baselines/reference/submodule/conformance/jsDeclarationsTypeReferences3.js
@@ -27,5 +27,4 @@ module.exports.A.B = {
 
 
 //// [index.d.ts]
-export var A = {};
-export {};
+export declare var A: {};
diff --git a/testdata/baselines/reference/submodule/conformance/jsDeclarationsTypeReferences3.js.diff b/testdata/baselines/reference/submodule/conformance/jsDeclarationsTypeReferences3.js.diff
index 2a594e8114..afd05f2739 100644
--- a/testdata/baselines/reference/submodule/conformance/jsDeclarationsTypeReferences3.js.diff
+++ b/testdata/baselines/reference/submodule/conformance/jsDeclarationsTypeReferences3.js.diff
@@ -23,5 +23,4 @@
 -}
 -import Something_1 = require("fs");
 -import Something = Something_1.Something;
-+export var A = {};
-+export {};
\ No newline at end of file
++export declare var A: {};
\ No newline at end of file
diff --git a/testdata/baselines/reference/submodule/conformance/moduleExportAliasElementAccessExpression.js b/testdata/baselines/reference/submodule/conformance/moduleExportAliasElementAccessExpression.js
index 184cf4cb72..65b2dbedb4 100644
--- a/testdata/baselines/reference/submodule/conformance/moduleExportAliasElementAccessExpression.js
+++ b/testdata/baselines/reference/submodule/conformance/moduleExportAliasElementAccessExpression.js
@@ -20,27 +20,8 @@ exports["Does not work yet"] = D;
 
 
 //// [moduleExportAliasElementAccessExpression.d.ts]
-export var D = D;
-export var Does not work yet = D;
-export {};
-
-
-//// [DtsFileErrors]
-
-
-out/moduleExportAliasElementAccessExpression.d.ts(2,17): error TS1005: ',' expected.
-out/moduleExportAliasElementAccessExpression.d.ts(2,21): error TS1005: ',' expected.
-out/moduleExportAliasElementAccessExpression.d.ts(2,26): error TS1005: ',' expected.
-
-
-==== out/moduleExportAliasElementAccessExpression.d.ts (3 errors) ====
-    export var D = D;
-    export var Does not work yet = D;
-                    ~~~
-!!! error TS1005: ',' expected.
-                        ~~~~
-!!! error TS1005: ',' expected.
-                             ~~~
-!!! error TS1005: ',' expected.
-    export {};
-    
\ No newline at end of file
+declare function D(): void;
+declare const _exported: typeof D;
+export { _exported as "D" };
+declare const _exported_1: typeof D;
+export { _exported_1 as "Does not work yet" };
diff --git a/testdata/baselines/reference/submodule/conformance/moduleExportAliasElementAccessExpression.js.diff b/testdata/baselines/reference/submodule/conformance/moduleExportAliasElementAccessExpression.js.diff
index 7783a7eb3e..5d2f55b2a9 100644
--- a/testdata/baselines/reference/submodule/conformance/moduleExportAliasElementAccessExpression.js.diff
+++ b/testdata/baselines/reference/submodule/conformance/moduleExportAliasElementAccessExpression.js.diff
@@ -18,27 +18,8 @@
  //// [moduleExportAliasElementAccessExpression.d.ts]
 -export function D(): void;
 -export { D as _Does_not_work_yet };
-+export var D = D;
-+export var Does not work yet = D;
-+export {};
-+
-+
-+//// [DtsFileErrors]
-+
-+
-+out/moduleExportAliasElementAccessExpression.d.ts(2,17): error TS1005: ',' expected.
-+out/moduleExportAliasElementAccessExpression.d.ts(2,21): error TS1005: ',' expected.
-+out/moduleExportAliasElementAccessExpression.d.ts(2,26): error TS1005: ',' expected.
-+
-+
-+==== out/moduleExportAliasElementAccessExpression.d.ts (3 errors) ====
-+    export var D = D;
-+    export var Does not work yet = D;
-+                    ~~~
-+!!! error TS1005: ',' expected.
-+                        ~~~~
-+!!! error TS1005: ',' expected.
-+                             ~~~
-+!!! error TS1005: ',' expected.
-+    export {};
-+    
\ No newline at end of file
++declare function D(): void;
++declare const _exported: typeof D;
++export { _exported as "D" };
++declare const _exported_1: typeof D;
++export { _exported_1 as "Does not work yet" };
\ No newline at end of file
diff --git a/testdata/baselines/reference/submodule/conformance/moduleExportDuplicateAlias.js b/testdata/baselines/reference/submodule/conformance/moduleExportDuplicateAlias.js
index 5efb46cf66..4ee7030d20 100644
--- a/testdata/baselines/reference/submodule/conformance/moduleExportDuplicateAlias.js
+++ b/testdata/baselines/reference/submodule/conformance/moduleExportDuplicateAlias.js
@@ -29,8 +29,7 @@ apply();
 
 
 //// [moduleExportAliasDuplicateAlias.d.ts]
-export var apply = undefined;
-export var apply = a;
-export {};
+export declare var apply: undefined;
+export declare var apply: undefined;
 //// [test.d.ts]
 export {};
diff --git a/testdata/baselines/reference/submodule/conformance/moduleExportDuplicateAlias.js.diff b/testdata/baselines/reference/submodule/conformance/moduleExportDuplicateAlias.js.diff
index 1f6798aa2b..da8d0fc2d2 100644
--- a/testdata/baselines/reference/submodule/conformance/moduleExportDuplicateAlias.js.diff
+++ b/testdata/baselines/reference/submodule/conformance/moduleExportDuplicateAlias.js.diff
@@ -19,8 +19,7 @@
  //// [moduleExportAliasDuplicateAlias.d.ts]
 -export { a as apply };
 -declare function a(): void;
-+export var apply = undefined;
-+export var apply = a;
-+export {};
++export declare var apply: undefined;
++export declare var apply: undefined;
  //// [test.d.ts]
  export {};
\ No newline at end of file
diff --git a/testdata/baselines/reference/submodule/conformance/moduleExportDuplicateAlias2.js b/testdata/baselines/reference/submodule/conformance/moduleExportDuplicateAlias2.js
index 32cd447fba..464a441258 100644
--- a/testdata/baselines/reference/submodule/conformance/moduleExportDuplicateAlias2.js
+++ b/testdata/baselines/reference/submodule/conformance/moduleExportDuplicateAlias2.js
@@ -30,9 +30,8 @@ apply();
 
 
 //// [moduleExportAliasDuplicateAlias.d.ts]
-export var apply = undefined;
-export var apply = a;
-export var apply = a;
-export {};
+export declare var apply: undefined;
+export declare var apply: undefined;
+export declare var apply: undefined;
 //// [test.d.ts]
 export {};
diff --git a/testdata/baselines/reference/submodule/conformance/moduleExportDuplicateAlias2.js.diff b/testdata/baselines/reference/submodule/conformance/moduleExportDuplicateAlias2.js.diff
index 547d966ad9..51dfb3c53a 100644
--- a/testdata/baselines/reference/submodule/conformance/moduleExportDuplicateAlias2.js.diff
+++ b/testdata/baselines/reference/submodule/conformance/moduleExportDuplicateAlias2.js.diff
@@ -20,9 +20,8 @@
  //// [moduleExportAliasDuplicateAlias.d.ts]
 -export { a as apply };
 -declare function a(): void;
-+export var apply = undefined;
-+export var apply = a;
-+export var apply = a;
-+export {};
++export declare var apply: undefined;
++export declare var apply: undefined;
++export declare var apply: undefined;
  //// [test.d.ts]
  export {};
\ No newline at end of file
diff --git a/testdata/baselines/reference/submodule/conformance/moduleExportDuplicateAlias3.js b/testdata/baselines/reference/submodule/conformance/moduleExportDuplicateAlias3.js
index ca8ba75bb5..1826f857f2 100644
--- a/testdata/baselines/reference/submodule/conformance/moduleExportDuplicateAlias3.js
+++ b/testdata/baselines/reference/submodule/conformance/moduleExportDuplicateAlias3.js
@@ -38,11 +38,10 @@ const result = apply.toFixed();
 
 
 //// [moduleExportAliasDuplicateAlias.d.ts]
-export var apply = undefined;
-export var apply = undefined;
-export var apply = a;
-export var apply = 'ok';
-export var apply = 1;
-export {};
+export declare var apply: undefined;
+export declare var apply: undefined;
+export declare var apply: undefined;
+export declare var apply: undefined;
+export declare var apply: undefined;
 //// [test.d.ts]
 export {};
diff --git a/testdata/baselines/reference/submodule/conformance/moduleExportDuplicateAlias3.js.diff b/testdata/baselines/reference/submodule/conformance/moduleExportDuplicateAlias3.js.diff
index 031199c202..e091ce0595 100644
--- a/testdata/baselines/reference/submodule/conformance/moduleExportDuplicateAlias3.js.diff
+++ b/testdata/baselines/reference/submodule/conformance/moduleExportDuplicateAlias3.js.diff
@@ -27,11 +27,10 @@
 -export const apply: "ok" | 1 | typeof a | undefined;
 -export { a as apply };
 -declare function a(): void;
-+export var apply = undefined;
-+export var apply = undefined;
-+export var apply = a;
-+export var apply = 'ok';
-+export var apply = 1;
-+export {};
++export declare var apply: undefined;
++export declare var apply: undefined;
++export declare var apply: undefined;
++export declare var apply: undefined;
++export declare var apply: undefined;
  //// [test.d.ts]
  export {};
\ No newline at end of file
diff --git a/testdata/baselines/reference/submodule/conformance/moduleExportsElementAccessAssignment.js b/testdata/baselines/reference/submodule/conformance/moduleExportsElementAccessAssignment.js
index 5e70503425..fd6eb83ea9 100644
--- a/testdata/baselines/reference/submodule/conformance/moduleExportsElementAccessAssignment.js
+++ b/testdata/baselines/reference/submodule/conformance/moduleExportsElementAccessAssignment.js
@@ -20,11 +20,22 @@ mod1.default;
 
 
 //// [mod1.d.ts]
-export var a = { x: "x" };
-export var b = { x: "x" };
-export var default = { x: "x" };
-export var c = { x: "x" };
-export var d = {};
-export {};
+export declare var a: {
+    x: string;
+};
+declare const _exported: {
+    x: string;
+};
+export { _exported as "b" };
+declare const _exported_1: {
+    x: string;
+};
+export { _exported_1 as "default" };
+declare const _exported_2: {
+    x: string;
+};
+export { _exported_2 as "c" };
+declare const _exported_3: {};
+export { _exported_3 as "d" };
 //// [mod2.d.ts]
 export {};
diff --git a/testdata/baselines/reference/submodule/conformance/moduleExportsElementAccessAssignment.js.diff b/testdata/baselines/reference/submodule/conformance/moduleExportsElementAccessAssignment.js.diff
index 5c413072ad..68d3a6f598 100644
--- a/testdata/baselines/reference/submodule/conformance/moduleExportsElementAccessAssignment.js.diff
+++ b/testdata/baselines/reference/submodule/conformance/moduleExportsElementAccessAssignment.js.diff
@@ -23,11 +23,22 @@
 -export namespace d {
 -    let e: number;
 -}
-+export var a = { x: "x" };
-+export var b = { x: "x" };
-+export var default = { x: "x" };
-+export var c = { x: "x" };
-+export var d = {};
-+export {};
++export declare var a: {
++    x: string;
++};
++declare const _exported: {
++    x: string;
++};
++export { _exported as "b" };
++declare const _exported_1: {
++    x: string;
++};
++export { _exported_1 as "default" };
++declare const _exported_2: {
++    x: string;
++};
++export { _exported_2 as "c" };
++declare const _exported_3: {};
++export { _exported_3 as "d" };
  //// [mod2.d.ts]
  export {};
\ No newline at end of file
diff --git a/testdata/baselines/reference/submodule/conformance/nestedDestructuringOfRequire.js b/testdata/baselines/reference/submodule/conformance/nestedDestructuringOfRequire.js
index 2d323ea43f..ea7a565f31 100644
--- a/testdata/baselines/reference/submodule/conformance/nestedDestructuringOfRequire.js
+++ b/testdata/baselines/reference/submodule/conformance/nestedDestructuringOfRequire.js
@@ -29,7 +29,8 @@ chalk;
 
 
 //// [mod1.d.ts]
-export var chalk = chalk;
-export {};
+export declare var chalk: {
+    grey: {};
+};
 //// [main.d.ts]
 export {};
diff --git a/testdata/baselines/reference/submodule/conformance/nestedDestructuringOfRequire.js.diff b/testdata/baselines/reference/submodule/conformance/nestedDestructuringOfRequire.js.diff
index 4fdb156b6f..09d98a3c3a 100644
--- a/testdata/baselines/reference/submodule/conformance/nestedDestructuringOfRequire.js.diff
+++ b/testdata/baselines/reference/submodule/conformance/nestedDestructuringOfRequire.js.diff
@@ -20,7 +20,8 @@
 -export namespace chalk {
 -    let grey: {};
 -}
-+export var chalk = chalk;
-+export {};
++export declare var chalk: {
++    grey: {};
++};
  //// [main.d.ts]
  export {};
\ No newline at end of file
diff --git a/testdata/tests/cases/compiler/jsDeclarationExportDefaultAssignmentCrash.ts b/testdata/tests/cases/compiler/jsDeclarationExportDefaultAssignmentCrash.ts
new file mode 100644
index 0000000000..9ffac97175
--- /dev/null
+++ b/testdata/tests/cases/compiler/jsDeclarationExportDefaultAssignmentCrash.ts
@@ -0,0 +1,9 @@
+// @allowJs: true
+// @checkJs: true
+// @outDir: ./out
+// @declaration: true
+// @filename: index.js
+
+exports.default = () => {
+    return 1234;
+}