microsoft · DanielRosenwasser · Jan 20, 2026 · Jan 20, 2026
diff --git a/tests/cases/fourslash/annotateWithTypeFromJSDoc1.ts b/tests/cases/fourslash/annotateWithTypeFromJSDoc1.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 // @Filename: test123.ts
 /////** @type {number} */
 ////var [|x|];

diff --git a/tests/cases/fourslash/annotateWithTypeFromJSDoc10.ts b/tests/cases/fourslash/annotateWithTypeFromJSDoc10.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 /////**
 //// * @param {?} x
 //// * @returns {number}

diff --git a/tests/cases/fourslash/annotateWithTypeFromJSDoc11.ts b/tests/cases/fourslash/annotateWithTypeFromJSDoc11.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 /////**
 //// * @param {?} x
 //// * @returns {number}

diff --git a/tests/cases/fourslash/annotateWithTypeFromJSDoc12.ts b/tests/cases/fourslash/annotateWithTypeFromJSDoc12.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 ////class C {
 ////    /**
 ////     * @return {...*}

diff --git a/tests/cases/fourslash/annotateWithTypeFromJSDoc17.ts b/tests/cases/fourslash/annotateWithTypeFromJSDoc17.ts
@@ -1,4 +1,5 @@
 /// <reference path='fourslash.ts' />
+// @strict: false
 ////class C {
 ////    /**
 ////     * @param {number} x - the first parameter

diff --git a/tests/cases/fourslash/annotateWithTypeFromJSDoc18.ts b/tests/cases/fourslash/annotateWithTypeFromJSDoc18.ts
@@ -1,4 +1,5 @@
 /// <reference path='fourslash.ts' />
+// @strict: false
 ////class C {
 ////    /** @param {number} value */
 ////    set c(value) { return value }

diff --git a/tests/cases/fourslash/annotateWithTypeFromJSDoc3.ts b/tests/cases/fourslash/annotateWithTypeFromJSDoc3.ts
@@ -1,4 +1,5 @@
 /// <reference path='fourslash.ts' />
+// @strict: false
 /////**
 //// * @param {number} x - the first parameter
 //// * @param {{ a: string, b: Date }} y - the most complex parameter

diff --git a/tests/cases/fourslash/annotateWithTypeFromJSDoc6.ts b/tests/cases/fourslash/annotateWithTypeFromJSDoc6.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 ////declare class C {
 ////    /** @type {number | null} */
 ////    p;

diff --git a/tests/cases/fourslash/annotateWithTypeFromJSDoc7.ts b/tests/cases/fourslash/annotateWithTypeFromJSDoc7.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 /////**
 //// * @param {number} x
 //// * @returns {number}

diff --git a/tests/cases/fourslash/annotateWithTypeFromJSDoc8.ts b/tests/cases/fourslash/annotateWithTypeFromJSDoc8.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 /////**
 //// * @param {number} x
 //// * @returns {number}

diff --git a/tests/cases/fourslash/annotateWithTypeFromJSDoc9.5.ts b/tests/cases/fourslash/annotateWithTypeFromJSDoc9.5.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 /////**
 //// * @template T
 //// * @param {T} x

diff --git a/tests/cases/fourslash/annotateWithTypeFromJSDoc9.ts b/tests/cases/fourslash/annotateWithTypeFromJSDoc9.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 /////**
 //// * @param {?} x
 //// * @returns {number}

diff --git a/tests/cases/fourslash/cloduleAsBaseClass.ts b/tests/cases/fourslash/cloduleAsBaseClass.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts'/>
 
+// @strict: false
 ////class A {
 ////    constructor(x: number) { }
 ////    foo() { }

diff --git a/tests/cases/fourslash/cloduleAsBaseClass2.ts b/tests/cases/fourslash/cloduleAsBaseClass2.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts'/>
 
+// @strict: false
 // @Filename: cloduleAsBaseClass2_0.ts
 ////class A {
 ////    constructor(x: number) { }

diff --git a/tests/cases/fourslash/cloduleTypeOf1.ts b/tests/cases/fourslash/cloduleTypeOf1.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts'/>
 
+// @strict: false
 ////class C<T> {
 ////    static foo(x: number) { }
 ////    x: T;

diff --git a/tests/cases/fourslash/codeFixAddMissingAsync2.ts b/tests/cases/fourslash/codeFixAddMissingAsync2.ts
@@ -1,4 +1,5 @@
 /// <reference path="fourslash.ts" />
+// @strict: false
 ////interface Stuff {
 ////    b: () => Promise<string>;
 ////}

diff --git a/tests/cases/fourslash/codeFixAddMissingDeclareProperty.ts b/tests/cases/fourslash/codeFixAddMissingDeclareProperty.ts
@@ -1,4 +1,5 @@
 /// <reference path='fourslash.ts' />
+// @strict: false
 // @useDefineForClassFields: true
 
 ////class B {

diff --git a/tests/cases/fourslash/codeFixAddMissingEnumMember12.ts b/tests/cases/fourslash/codeFixAddMissingEnumMember12.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 ////const x; // this is x
 ////
 ////// this is E

diff --git a/tests/cases/fourslash/codeFixAddMissingProperties1.ts b/tests/cases/fourslash/codeFixAddMissingProperties1.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 ////interface Foo {
 ////    a: number;
 ////    b: string;

diff --git a/tests/cases/fourslash/codeFixAddMissingProperties33.ts b/tests/cases/fourslash/codeFixAddMissingProperties33.ts
@@ -1,5 +1,6 @@
 /// <reference path="fourslash.ts" />
 
+// @strict: false
 ////interface Foo {
 ////    a: number;
 ////    b: string;

diff --git a/tests/cases/fourslash/codeFixAddMissingProperties37.ts b/tests/cases/fourslash/codeFixAddMissingProperties37.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 ////interface I {
 ////    x: number;
 ////    y: number;

diff --git a/tests/cases/fourslash/codeFixAddMissingProperties43.ts b/tests/cases/fourslash/codeFixAddMissingProperties43.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 ////interface Foo {
 ////    a: number;
 ////    b: string;

diff --git a/tests/cases/fourslash/codeFixAddMissingProperties44.ts b/tests/cases/fourslash/codeFixAddMissingProperties44.ts
@@ -1,4 +1,5 @@
 /// <reference path='fourslash.ts' />
+// @strict: false
 // @lib: es2020
 // @target: es2020
 

diff --git a/tests/cases/fourslash/codeFixAddMissingProperties6.ts b/tests/cases/fourslash/codeFixAddMissingProperties6.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 ////interface I {
 ////    x: number;
 ////    y: number;

diff --git a/tests/cases/fourslash/codeFixAwaitInSyncFunction6.5.ts b/tests/cases/fourslash/codeFixAwaitInSyncFunction6.5.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 ////const f = promise => {
 ////    await promise;
 ////}

diff --git a/tests/cases/fourslash/codeFixAwaitInSyncFunction6.ts b/tests/cases/fourslash/codeFixAwaitInSyncFunction6.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 ////const f = (promise) => {
 ////    await promise;
 ////}

diff --git a/tests/cases/fourslash/codeFixCannotFindModule_suggestion.ts b/tests/cases/fourslash/codeFixCannotFindModule_suggestion.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 // @moduleResolution: bundler
 // @Filename: /node_modules/abs/subModule.js
 ////export const x = 0;

diff --git a/tests/cases/fourslash/codeFixChangeJSDocSyntax15.ts b/tests/cases/fourslash/codeFixChangeJSDocSyntax15.ts
@@ -1,4 +1,5 @@
 /// <reference path='fourslash.ts' />
+// @strict: false
 //// var f = <[|function(number?): number|]>(x => x);
 
 verify.codeFix({

diff --git a/tests/cases/fourslash/codeFixClassExtendAbstractSomePropertiesPresent.ts b/tests/cases/fourslash/codeFixClassExtendAbstractSomePropertiesPresent.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 // @noImplicitOverride: true
 //// abstract class A {
 ////    abstract x: number;

diff --git a/tests/cases/fourslash/codeFixClassImplementClassMemberAnonymousClass.ts b/tests/cases/fourslash/codeFixClassImplementClassMemberAnonymousClass.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 //// class A {
 ////     foo() {
 ////         return class { x: number; }

diff --git a/tests/cases/fourslash/codeFixClassImplementClassPropertyModifiers.ts b/tests/cases/fourslash/codeFixClassImplementClassPropertyModifiers.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 ////abstract class A {
 ////    abstract x: number;
 ////    private y: number;

diff --git a/tests/cases/fourslash/codeFixClassImplementClassPropertyTypeQuery.ts b/tests/cases/fourslash/codeFixClassImplementClassPropertyTypeQuery.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 ////class A {
 ////    A: typeof A;
 ////}

diff --git a/tests/cases/fourslash/codeFixClassImplementDeepInheritance.ts b/tests/cases/fourslash/codeFixClassImplementDeepInheritance.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 ////// Referenced throughout the inheritance chain.
 ////interface I0 { a: number }
 ////

diff --git a/tests/cases/fourslash/codeFixClassImplementInterfaceComputedPropertyNameWellKnownSymbols.ts b/tests/cases/fourslash/codeFixClassImplementInterfaceComputedPropertyNameWellKnownSymbols.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 // @lib: es2017
 
 ////interface I<Species> {

diff --git a/tests/cases/fourslash/codeFixClassImplementInterfaceDuplicateMember2.ts b/tests/cases/fourslash/codeFixClassImplementInterfaceDuplicateMember2.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 //// interface I1 {
 ////     x: number;
 //// }

diff --git a/tests/cases/fourslash/codeFixClassImplementInterfaceHeritageClauseAlreadyHaveMember.ts b/tests/cases/fourslash/codeFixClassImplementInterfaceHeritageClauseAlreadyHaveMember.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 //// class Base {
 ////     foo: number;
 //// }

diff --git a/tests/cases/fourslash/codeFixClassImplementInterfaceMultipleImplements1.ts b/tests/cases/fourslash/codeFixClassImplementInterfaceMultipleImplements1.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 //// interface I1 {
 ////     x: number;
 //// }

diff --git a/tests/cases/fourslash/codeFixClassImplementInterfaceMultipleImplements2.ts b/tests/cases/fourslash/codeFixClassImplementInterfaceMultipleImplements2.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 //// interface I1 {
 ////     x: number;
 //// }

diff --git a/tests/cases/fourslash/codeFixClassImplementInterfaceMultipleImplementsIntersection2.ts b/tests/cases/fourslash/codeFixClassImplementInterfaceMultipleImplementsIntersection2.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 //// interface I1 {
 ////     x: number;
 //// }

diff --git a/tests/cases/fourslash/codeFixClassImplementInterfaceOptionalProperty.ts b/tests/cases/fourslash/codeFixClassImplementInterfaceOptionalProperty.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 ////interface IPerson {
 ////    name: string;
 ////    birthday?: string;

diff --git a/tests/cases/fourslash/codeFixClassImplementInterfaceSomePropertiesPresent.ts b/tests/cases/fourslash/codeFixClassImplementInterfaceSomePropertiesPresent.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 ////
 //// interface I {
 ////     x: number;

diff --git a/tests/cases/fourslash/codeFixCorrectReturnValue10.ts b/tests/cases/fourslash/codeFixCorrectReturnValue10.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 //// const a: ((() => number) | (() => undefined)) = () => { 1 }
 
 verify.codeFixAvailable([

diff --git a/tests/cases/fourslash/codeFixCorrectReturnValue18.ts b/tests/cases/fourslash/codeFixCorrectReturnValue18.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 //@Filename: file.tsx
 //// declare namespace JSX {
 ////     interface Element { }

diff --git a/tests/cases/fourslash/codeFixCorrectReturnValue19.ts b/tests/cases/fourslash/codeFixCorrectReturnValue19.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 //@Filename: file.tsx
 //// declare namespace JSX {
 ////     interface Element { }

diff --git a/tests/cases/fourslash/codeFixCorrectReturnValue20.ts b/tests/cases/fourslash/codeFixCorrectReturnValue20.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 //@Filename: file.tsx
 //// declare namespace JSX {
 ////     interface Element { }

diff --git a/tests/cases/fourslash/codeFixCorrectReturnValue8.ts b/tests/cases/fourslash/codeFixCorrectReturnValue8.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 //// function Foo (a: (() => number) | (() => undefined) ) { a() }
 //// Foo(() => { 1 })
 

diff --git a/tests/cases/fourslash/codeFixDisableJsDiagnosticsInFile6.ts b/tests/cases/fourslash/codeFixDisableJsDiagnosticsInFile6.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 // @allowjs: true
 // @noEmit: true
 // @checkJs: true

diff --git a/tests/cases/fourslash/codeFixDisableJsDiagnosticsInFile7.ts b/tests/cases/fourslash/codeFixDisableJsDiagnosticsInFile7.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 // @allowjs: true
 // @noEmit: true
 // @checkJs: true

diff --git a/tests/cases/fourslash/codeFixDisableJsDiagnosticsInFile8.ts b/tests/cases/fourslash/codeFixDisableJsDiagnosticsInFile8.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 // @allowjs: true
 // @noEmit: true
 // @checkJs: true

diff --git a/tests/cases/fourslash/codeFixForgottenThisPropertyAccess01.ts b/tests/cases/fourslash/codeFixForgottenThisPropertyAccess01.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 // @Filename: /a.ts
 ////export const foo = 0;
 

diff --git a/tests/cases/fourslash/codeFixForgottenThisPropertyAccess02.ts b/tests/cases/fourslash/codeFixForgottenThisPropertyAccess02.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 ////class C {
 ////    constructor(public foo) {
 ////    }

diff --git a/tests/cases/fourslash/codeFixForgottenThisPropertyAccess03.ts b/tests/cases/fourslash/codeFixForgottenThisPropertyAccess03.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 ////class C {
 ////    foo: number;
 ////    constructor() {[|

diff --git a/tests/cases/fourslash/codeFixInferFromUsageConstructor.ts b/tests/cases/fourslash/codeFixInferFromUsageConstructor.ts
@@ -1,4 +1,5 @@
 /// <reference path='fourslash.ts' />
+// @strict: false
 // @strictNullChecks: true
 
 ////class TokenType {

diff --git a/tests/cases/fourslash/codeFixInferFromUsageConstructorFunctionJS.ts b/tests/cases/fourslash/codeFixInferFromUsageConstructorFunctionJS.ts
@@ -1,4 +1,5 @@
 /// <reference path='fourslash.ts' />
+// @strict: false
 // @allowJs: true
 // @checkJs: true
 // @noImplicitAny: true

diff --git a/tests/cases/fourslash/codeFixInferFromUsageGetter2.ts b/tests/cases/fourslash/codeFixInferFromUsageGetter2.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 // @noImplicitAny: true
 ////class C {
 ////    [|get x() |]{

diff --git a/tests/cases/fourslash/codeFixInferFromUsageInaccessibleTypes.ts b/tests/cases/fourslash/codeFixInferFromUsageInaccessibleTypes.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 // @noImplicitAny: true
 ////function f1(a) { a; }
 ////function h1() {

diff --git a/tests/cases/fourslash/codeFixInferFromUsageOptionalParam.ts b/tests/cases/fourslash/codeFixInferFromUsageOptionalParam.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 // @noImplicitAny: true
 ////function f([|a? |]){
 ////    a;

diff --git a/tests/cases/fourslash/codeFixInferFromUsageOptionalParamJS.ts b/tests/cases/fourslash/codeFixInferFromUsageOptionalParamJS.ts
@@ -1,5 +1,6 @@
 /// <reference path='fourslash.ts' />
 
+// @strict: false
 // @allowJs: true
 // @checkJs: true
 // @noImplicitAny: true