microsoft · DanielRosenwasser · Jan 13, 2026 · Jan 13, 2026 · Jan 13, 2026 · Jan 13, 2026
diff --git a/tests/baselines/reference/tsserver/fourslashServer/declarationMapsEnableMapping_NoInline.js b/tests/baselines/reference/tsserver/fourslashServer/declarationMapsEnableMapping_NoInline.js
@@ -74,6 +74,7 @@ instance.methodName({member: 12});
 //// [/home/src/workspaces/project/tsconfig.json]
 {
     "compilerOptions": {
+        "strict": false,
         "outDir": "./dist",
         "inlineSourceMap": true,
         "declaration": true,
@@ -101,6 +102,7 @@ Info seq  [hh:mm:ss:mss] Config: /home/src/workspaces/project/tsconfig.json : {
   "/home/src/workspaces/project/index.ts"
  ],
  "options": {
+  "strict": false,
   "outDir": "/home/src/workspaces/project/dist",
   "inlineSourceMap": true,
   "declaration": true,
@@ -181,7 +183,7 @@ Info seq  [hh:mm:ss:mss] 	Files (4)
 	/home/src/tslibs/TS/Lib/lib.d.ts Text-1 lib.d.ts-Text
 	/home/src/tslibs/TS/Lib/lib.decorators.d.ts Text-1 lib.decorators.d.ts-Text
 	/home/src/tslibs/TS/Lib/lib.decorators.legacy.d.ts Text-1 lib.decorators.legacy.d.ts-Text
-	/home/src/workspaces/project/tsconfig.json SVC-1-0 "{\n    \"compilerOptions\": {\n        \"outDir\": \"./dist\",\n        \"inlineSourceMap\": true,\n        \"declaration\": true,\n        \"declarationMap\": true,\n        \"newLine\": \"lf\",\n    },\n    \"files\": [\"/home/src/workspaces/project/index.ts\"],\n}"
+	/home/src/workspaces/project/tsconfig.json SVC-1-0 "{\n    \"compilerOptions\": {\n        \"strict\": false,\n        \"outDir\": \"./dist\",\n        \"inlineSourceMap\": true,\n        \"declaration\": true,\n        \"declarationMap\": true,\n        \"newLine\": \"lf\",\n    },\n    \"files\": [\"/home/src/workspaces/project/index.ts\"],\n}"
 
 
 	../../tslibs/TS/Lib/lib.d.ts

diff --git a/...elines/reference/tsserver/fourslashServer/declarationMapsEnableMapping_NoInlineSources.js b/...elines/reference/tsserver/fourslashServer/declarationMapsEnableMapping_NoInlineSources.js
@@ -74,6 +74,7 @@ instance.methodName({member: 12});
 //// [/home/src/workspaces/project/tsconfig.json]
 {
     "compilerOptions": {
+        "strict": false,
         "outDir": "./dist",
         "inlineSourceMap": true,
         "inlineSources": true,
@@ -102,6 +103,7 @@ Info seq  [hh:mm:ss:mss] Config: /home/src/workspaces/project/tsconfig.json : {
   "/home/src/workspaces/project/index.ts"
  ],
  "options": {
+  "strict": false,
   "outDir": "/home/src/workspaces/project/dist",
   "inlineSourceMap": true,
   "inlineSources": true,
@@ -183,7 +185,7 @@ Info seq  [hh:mm:ss:mss] 	Files (4)
 	/home/src/tslibs/TS/Lib/lib.d.ts Text-1 lib.d.ts-Text
 	/home/src/tslibs/TS/Lib/lib.decorators.d.ts Text-1 lib.decorators.d.ts-Text
 	/home/src/tslibs/TS/Lib/lib.decorators.legacy.d.ts Text-1 lib.decorators.legacy.d.ts-Text
-	/home/src/workspaces/project/tsconfig.json SVC-1-0 "{\n    \"compilerOptions\": {\n        \"outDir\": \"./dist\",\n        \"inlineSourceMap\": true,\n        \"inlineSources\": true,\n        \"declaration\": true,\n        \"declarationMap\": true,\n        \"newLine\": \"lf\",\n    },\n    \"files\": [\"/home/src/workspaces/project/index.ts\"],\n}"
+	/home/src/workspaces/project/tsconfig.json SVC-1-0 "{\n    \"compilerOptions\": {\n        \"strict\": false,\n        \"outDir\": \"./dist\",\n        \"inlineSourceMap\": true,\n        \"inlineSources\": true,\n        \"declaration\": true,\n        \"declarationMap\": true,\n        \"newLine\": \"lf\",\n    },\n    \"files\": [\"/home/src/workspaces/project/index.ts\"],\n}"
 
 
 	../../tslibs/TS/Lib/lib.d.ts

diff --git a/...baselines/reference/tsserver/fourslashServer/declarationMapsGeneratedMapsEnableMapping.js b/...baselines/reference/tsserver/fourslashServer/declarationMapsGeneratedMapsEnableMapping.js
@@ -74,6 +74,7 @@ instance.methodName({member: 12});
 //// [/home/src/workspaces/project/tsconfig.json]
 {
     "compilerOptions": {
+        "strict": false,
         "outDir": "./dist",
         "declaration": true,
         "declarationMap": true,
@@ -100,6 +101,7 @@ Info seq  [hh:mm:ss:mss] Config: /home/src/workspaces/project/tsconfig.json : {
   "/home/src/workspaces/project/index.ts"
  ],
  "options": {
+  "strict": false,
   "outDir": "/home/src/workspaces/project/dist",
   "declaration": true,
   "declarationMap": true,
@@ -179,7 +181,7 @@ Info seq  [hh:mm:ss:mss] 	Files (4)
 	/home/src/tslibs/TS/Lib/lib.d.ts Text-1 lib.d.ts-Text
 	/home/src/tslibs/TS/Lib/lib.decorators.d.ts Text-1 lib.decorators.d.ts-Text
 	/home/src/tslibs/TS/Lib/lib.decorators.legacy.d.ts Text-1 lib.decorators.legacy.d.ts-Text
-	/home/src/workspaces/project/tsconfig.json SVC-1-0 "{\n    \"compilerOptions\": {\n        \"outDir\": \"./dist\",\n        \"declaration\": true,\n        \"declarationMap\": true,\n        \"newLine\": \"lf\",\n    },\n    \"files\": [\"/home/src/workspaces/project/index.ts\"],\n}"
+	/home/src/workspaces/project/tsconfig.json SVC-1-0 "{\n    \"compilerOptions\": {\n        \"strict\": false,\n        \"outDir\": \"./dist\",\n        \"declaration\": true,\n        \"declarationMap\": true,\n        \"newLine\": \"lf\",\n    },\n    \"files\": [\"/home/src/workspaces/project/index.ts\"],\n}"
 
 
 	../../tslibs/TS/Lib/lib.d.ts

diff --git a/...aselines/reference/tsserver/fourslashServer/declarationMapsGeneratedMapsEnableMapping2.js b/...aselines/reference/tsserver/fourslashServer/declarationMapsGeneratedMapsEnableMapping2.js
@@ -77,6 +77,7 @@ instance.methodName({member: 12});
 //// [/home/src/workspaces/project/tsconfig.json]
 {
     "compilerOptions": {
+        "strict": false,
         "outDir": "./dist",
         "sourceMap": true,
         "sourceRoot": "/home/src/workspaces/project/",
@@ -105,6 +106,7 @@ Info seq  [hh:mm:ss:mss] Config: /home/src/workspaces/project/tsconfig.json : {
   "/home/src/workspaces/project/index.ts"
  ],
  "options": {
+  "strict": false,
   "outDir": "/home/src/workspaces/project/dist",
   "sourceMap": true,
   "sourceRoot": "/home/src/workspaces/project/",
@@ -186,7 +188,7 @@ Info seq  [hh:mm:ss:mss] 	Files (4)
 	/home/src/tslibs/TS/Lib/lib.d.ts Text-1 lib.d.ts-Text
 	/home/src/tslibs/TS/Lib/lib.decorators.d.ts Text-1 lib.decorators.d.ts-Text
 	/home/src/tslibs/TS/Lib/lib.decorators.legacy.d.ts Text-1 lib.decorators.legacy.d.ts-Text
-	/home/src/workspaces/project/tsconfig.json SVC-1-0 "{\n    \"compilerOptions\": {\n        \"outDir\": \"./dist\",\n        \"sourceMap\": true,\n        \"sourceRoot\": \"/home/src/workspaces/project/\",\n        \"declaration\": true,\n        \"declarationMap\": true,\n        \"newLine\": \"lf\",\n    },\n    \"files\": [\"/home/src/workspaces/project/index.ts\"],\n}"
+	/home/src/workspaces/project/tsconfig.json SVC-1-0 "{\n    \"compilerOptions\": {\n        \"strict\": false,\n        \"outDir\": \"./dist\",\n        \"sourceMap\": true,\n        \"sourceRoot\": \"/home/src/workspaces/project/\",\n        \"declaration\": true,\n        \"declarationMap\": true,\n        \"newLine\": \"lf\",\n    },\n    \"files\": [\"/home/src/workspaces/project/index.ts\"],\n}"
 
 
 	../../tslibs/TS/Lib/lib.d.ts

diff --git a/...aselines/reference/tsserver/fourslashServer/declarationMapsGeneratedMapsEnableMapping3.js b/...aselines/reference/tsserver/fourslashServer/declarationMapsGeneratedMapsEnableMapping3.js
@@ -74,6 +74,7 @@ instance.methodName({member: 12});
 //// [/home/src/workspaces/project/tsconfig.json]
 {
     "compilerOptions": {
+        "strict": false,
         "outDir": "./dist",
         "sourceRoot": "/home/src/workspaces/project/",
         "declaration": true,
@@ -101,6 +102,7 @@ Info seq  [hh:mm:ss:mss] Config: /home/src/workspaces/project/tsconfig.json : {
   "/home/src/workspaces/project/index.ts"
  ],
  "options": {
+  "strict": false,
   "outDir": "/home/src/workspaces/project/dist",
   "sourceRoot": "/home/src/workspaces/project/",
   "declaration": true,
@@ -167,11 +169,11 @@ Info seq  [hh:mm:ss:mss] event:
         "diagnostics": [
           {
             "start": {
-              "line": 4,
+              "line": 5,
               "offset": 9
             },
             "end": {
-              "line": 4,
+              "line": 5,
               "offset": 21
             },
             "text": "Option 'sourceRoot can only be used when either option '--inlineSourceMap' or option '--sourceMap' is provided.",
@@ -196,7 +198,7 @@ Info seq  [hh:mm:ss:mss] 	Files (4)
 	/home/src/tslibs/TS/Lib/lib.d.ts Text-1 lib.d.ts-Text
 	/home/src/tslibs/TS/Lib/lib.decorators.d.ts Text-1 lib.decorators.d.ts-Text
 	/home/src/tslibs/TS/Lib/lib.decorators.legacy.d.ts Text-1 lib.decorators.legacy.d.ts-Text
-	/home/src/workspaces/project/tsconfig.json SVC-1-0 "{\n    \"compilerOptions\": {\n        \"outDir\": \"./dist\",\n        \"sourceRoot\": \"/home/src/workspaces/project/\",\n        \"declaration\": true,\n        \"declarationMap\": true,\n        \"newLine\": \"lf\",\n    },\n    \"files\": [\"/home/src/workspaces/project/index.ts\"],\n}"
+	/home/src/workspaces/project/tsconfig.json SVC-1-0 "{\n    \"compilerOptions\": {\n        \"strict\": false,\n        \"outDir\": \"./dist\",\n        \"sourceRoot\": \"/home/src/workspaces/project/\",\n        \"declaration\": true,\n        \"declarationMap\": true,\n        \"newLine\": \"lf\",\n    },\n    \"files\": [\"/home/src/workspaces/project/index.ts\"],\n}"
 
 
 	../../tslibs/TS/Lib/lib.d.ts
@@ -442,11 +444,11 @@ Info seq  [hh:mm:ss:mss] event:
         "diagnostics": [
           {
             "start": {
-              "line": 4,
+              "line": 5,
               "offset": 9
             },
             "end": {
-              "line": 4,
+              "line": 5,
               "offset": 21
             },
             "text": "Option 'sourceRoot can only be used when either option '--inlineSourceMap' or option '--sourceMap' is provided.",

diff --git a/...rence/tsserver/fourslashServer/declarationMapsGoToDefinitionSameNameDifferentDirectory.js b/...rence/tsserver/fourslashServer/declarationMapsGoToDefinitionSameNameDifferentDirectory.js
@@ -65,6 +65,7 @@ class Button extends Control {
     "$schema": "http://json.schemastore.org/tsconfig",
     "compileOnSave": true,
     "compilerOptions": {
+      "strict": false,
       "sourceMap": true,
       "declaration": true,
       "declarationMap": true
@@ -201,6 +202,7 @@ Info seq  [hh:mm:ss:mss] Config: /tests/cases/fourslash/server/buttonClass/tscon
   "/tests/cases/fourslash/server/BaseClass/Source.d.ts"
  ],
  "options": {
+  "strict": false,
   "sourceMap": true,
   "declaration": true,
   "declarationMap": true,

diff --git a/tests/cases/compiler/ClassDeclaration10.ts b/tests/cases/compiler/ClassDeclaration10.ts
@@ -1,3 +1,4 @@
+// @strict: false
 class C {
    constructor();
    foo();

diff --git a/tests/cases/compiler/ClassDeclaration13.ts b/tests/cases/compiler/ClassDeclaration13.ts
@@ -1,3 +1,4 @@
+// @strict: false
 class C {
    foo();
    bar() { }

diff --git a/tests/cases/compiler/ClassDeclaration14.ts b/tests/cases/compiler/ClassDeclaration14.ts
@@ -1,3 +1,4 @@
+// @strict: false
 class C {
    foo();
    constructor();

diff --git a/tests/cases/compiler/ClassDeclaration15.ts b/tests/cases/compiler/ClassDeclaration15.ts
@@ -1,3 +1,4 @@
+// @strict: false
 class C {
    foo();
    constructor() { }

diff --git a/tests/cases/compiler/ClassDeclaration21.ts b/tests/cases/compiler/ClassDeclaration21.ts
@@ -1,3 +1,4 @@
+// @strict: false
 class C {
     0();
     1() { }

diff --git a/tests/cases/compiler/ClassDeclaration22.ts b/tests/cases/compiler/ClassDeclaration22.ts
@@ -1,3 +1,4 @@
+// @strict: false
 class C {
     "foo"();
     "bar"() { }

diff --git a/tests/cases/compiler/ClassDeclaration26.ts b/tests/cases/compiler/ClassDeclaration26.ts
@@ -1,3 +1,4 @@
+// @strict: false
 class C {
     public const var export foo = 10;
 

diff --git a/tests/cases/compiler/ClassDeclaration9.ts b/tests/cases/compiler/ClassDeclaration9.ts
@@ -1,3 +1,4 @@
+// @strict: false
 class C {
    foo();
 }
diff --git a/tests/cases/compiler/ClassDeclarationWithInvalidConstOnPropertyDeclaration2.ts b/tests/cases/compiler/ClassDeclarationWithInvalidConstOnPropertyDeclaration2.ts
@@ -1,3 +1,4 @@
+// @strict: false
 class C {
     const
     x = 10;

diff --git a/tests/cases/compiler/accessorDeclarationEmitJs.ts b/tests/cases/compiler/accessorDeclarationEmitJs.ts
@@ -1,3 +1,4 @@
+// @strict: false
 // @allowJs: true
 // @checkJs: true
 // @declaration: true

diff --git a/tests/cases/compiler/accessorParameterAccessibilityModifier.ts b/tests/cases/compiler/accessorParameterAccessibilityModifier.ts
@@ -1,3 +1,4 @@
+// @strict: false
 // @target: es5
 
 class C {

diff --git a/tests/cases/compiler/accessorWithInitializer.ts b/tests/cases/compiler/accessorWithInitializer.ts
@@ -1,3 +1,4 @@
+// @strict: false
 // @target: es5
 
 class C {

diff --git a/tests/cases/compiler/accessorWithRestParam.ts b/tests/cases/compiler/accessorWithRestParam.ts
@@ -1,3 +1,4 @@
+// @strict: false
 // @target: es5
 
 class C {

diff --git a/tests/cases/compiler/accessorWithoutBody1.ts b/tests/cases/compiler/accessorWithoutBody1.ts
@@ -1,2 +1,3 @@
+// @strict: false
 // @target: ES5
 var v = { get foo() }
diff --git a/tests/cases/compiler/accessorWithoutBody2.ts b/tests/cases/compiler/accessorWithoutBody2.ts
@@ -1,2 +1,3 @@
+// @strict: false
 // @target: ES5
 var v = { set foo(a) }
diff --git a/tests/cases/compiler/accessorsEmit.ts b/tests/cases/compiler/accessorsEmit.ts
@@ -1,3 +1,4 @@
+// @strict: false
 class Result { }
 
 class Test {

diff --git a/tests/cases/compiler/allowJscheckJsTypeParameterNoCrash.ts b/tests/cases/compiler/allowJscheckJsTypeParameterNoCrash.ts
@@ -1,3 +1,4 @@
+// @strict: false
 // @checkJs: true
 // @allowJs: true
 // @outDir: ./dist

diff --git a/tests/cases/compiler/allowSyntheticDefaultImports10.ts b/tests/cases/compiler/allowSyntheticDefaultImports10.ts
@@ -1,3 +1,4 @@
+// @strict: false
 // @allowSyntheticDefaultImports: true
 // @module: commonjs
 // @Filename: b.d.ts

diff --git a/tests/cases/compiler/allowSyntheticDefaultImports7.ts b/tests/cases/compiler/allowSyntheticDefaultImports7.ts
@@ -1,3 +1,4 @@
+// @strict: false
 // @module: system
 // @Filename: b.d.ts
 export function foo();

diff --git a/tests/cases/compiler/allowSyntheticDefaultImports8.ts b/tests/cases/compiler/allowSyntheticDefaultImports8.ts
@@ -1,3 +1,4 @@
+// @strict: false
 // @allowSyntheticDefaultImports: false
 // @module: system
 // @Filename: b.d.ts

diff --git a/tests/cases/compiler/allowSyntheticDefaultImports9.ts b/tests/cases/compiler/allowSyntheticDefaultImports9.ts
@@ -1,3 +1,4 @@
+// @strict: false
 // @allowSyntheticDefaultImports: true
 // @module: commonjs
 // @Filename: b.d.ts

diff --git a/tests/cases/compiler/ambientClassDeclarationWithExtends.ts b/tests/cases/compiler/ambientClassDeclarationWithExtends.ts
@@ -1,3 +1,4 @@
+// @strict: false
 // @Filename: ambientClassDeclarationExtends_singleFile.ts
 declare class A { }
 declare class B extends A { }

diff --git a/tests/cases/compiler/ambientClassOverloadForFunction.ts b/tests/cases/compiler/ambientClassOverloadForFunction.ts
@@ -1,2 +1,3 @@
+// @strict: false
 declare class foo{};
 function foo() { return null; }
diff --git a/tests/cases/compiler/ambientFundule.ts b/tests/cases/compiler/ambientFundule.ts
@@ -1,3 +1,4 @@
+// @strict: false
 declare function f();
 declare namespace f { var x }
 declare function f(x);
diff --git a/tests/cases/compiler/ambientWithStatements.ts b/tests/cases/compiler/ambientWithStatements.ts
@@ -1,3 +1,4 @@
+// @strict: false
 declare namespace M {
     break;
     continue;

diff --git a/tests/cases/compiler/ambiguousGenericAssertion1.ts b/tests/cases/compiler/ambiguousGenericAssertion1.ts
@@ -1,3 +1,4 @@
+// @strict: false
 function f<T>(x: T): T { return null; }
 var r = <T>(x: T) => x;
 var r2 = < <T>(x: T) => T>f; // valid

diff --git a/tests/cases/compiler/ambiguousOverload.ts b/tests/cases/compiler/ambiguousOverload.ts
@@ -1,3 +1,4 @@
+// @strict: false
 function foof(bar: string, y): number;
 function foof(bar: string, x): string;
 function foof(bar: any): any { return bar };

diff --git a/tests/cases/compiler/ambiguousOverloadResolution.ts b/tests/cases/compiler/ambiguousOverloadResolution.ts
@@ -1,3 +1,4 @@
+// @strict: false
 class A { }
 class B extends A { x: number; }
 

diff --git a/tests/cases/compiler/amdLikeInputDeclarationEmit.ts b/tests/cases/compiler/amdLikeInputDeclarationEmit.ts
@@ -1,3 +1,4 @@
+// @strict: false
 // @declaration: true
 // @declarationDir: definitions
 // @emitDeclarationOnly: true

diff --git a/tests/cases/compiler/anyAsReturnTypeForNewOnCall.ts b/tests/cases/compiler/anyAsReturnTypeForNewOnCall.ts
@@ -1,3 +1,4 @@
+// @strict: false
 function Point(x, y) {
 
  this.x = x;

diff --git a/tests/cases/compiler/anyIdenticalToItself.ts b/tests/cases/compiler/anyIdenticalToItself.ts
@@ -1,3 +1,4 @@
+// @strict: false
 function foo(x: any);
 function foo(x: any);
 function foo(x: any, y: number) { }

diff --git a/tests/cases/compiler/argumentsAsPropertyName.ts b/tests/cases/compiler/argumentsAsPropertyName.ts
@@ -1,3 +1,4 @@
+// @strict: false
 // target: es5
 type MyType = {
     arguments: Array<string>

diff --git a/tests/cases/compiler/argumentsAsPropertyName2.ts b/tests/cases/compiler/argumentsAsPropertyName2.ts
@@ -1,3 +1,4 @@
+// @strict: false
 // target: es5
 
 function foo() {

diff --git a/tests/cases/compiler/argumentsBindsToFunctionScopeArgumentList.ts b/tests/cases/compiler/argumentsBindsToFunctionScopeArgumentList.ts
@@ -1,3 +1,4 @@
+// @strict: false
 var arguments = 10;
 function foo(a) {
     arguments = 10;  /// This shouldnt be of type number and result in error.

diff --git a/tests/cases/compiler/argumentsObjectCreatesRestForJs.ts b/tests/cases/compiler/argumentsObjectCreatesRestForJs.ts
@@ -1,3 +1,4 @@
+// @strict: false
 // @checkJs: true
 // @allowJs: true
 // @Filename: main.js

diff --git a/tests/cases/compiler/argumentsPropertyNameInJsMode1.ts b/tests/cases/compiler/argumentsPropertyNameInJsMode1.ts
@@ -1,3 +1,4 @@
+// @strict: false
 // @allowJs: true
 // @checkJs: true
 // @declaration: true

diff --git a/tests/cases/compiler/argumentsPropertyNameInJsMode2.ts b/tests/cases/compiler/argumentsPropertyNameInJsMode2.ts
@@ -1,3 +1,4 @@
+// @strict: false
 // @allowJs: true
 // @checkJs: true
 // @declaration: true

diff --git a/tests/cases/compiler/argumentsReferenceInObjectLiteral_Js.ts b/tests/cases/compiler/argumentsReferenceInObjectLiteral_Js.ts
@@ -1,3 +1,4 @@
+// @strict: false
 // @checkJs: true
 // @allowJs: true
 // @target: es6

diff --git a/tests/cases/compiler/arityErrorRelatedSpanBindingPattern.ts b/tests/cases/compiler/arityErrorRelatedSpanBindingPattern.ts
@@ -1,3 +1,4 @@
+// @strict: false
 function foo(a, b, {c}): void {}
 
 function bar(a, b, [c]): void {}

diff --git a/tests/cases/compiler/arrayAssignmentTest2.ts b/tests/cases/compiler/arrayAssignmentTest2.ts
@@ -1,3 +1,4 @@
+// @strict: false
 interface I1 {
 	IM1():void[];
 }

diff --git a/tests/cases/compiler/arrayAssignmentTest4.ts b/tests/cases/compiler/arrayAssignmentTest4.ts
@@ -1,3 +1,4 @@
+// @strict: false
 
 
 class C3 {

diff --git a/tests/cases/compiler/arrayFromAsync.ts b/tests/cases/compiler/arrayFromAsync.ts
@@ -1,3 +1,4 @@
+// @strict: false
 // @module: esnext
 // @target: esnext
 

diff --git a/tests/cases/compiler/arrayIndexWithArrayFails.ts b/tests/cases/compiler/arrayIndexWithArrayFails.ts
@@ -1,3 +1,4 @@
+// @strict: false
 declare const arr1: (string | string[])[];
 declare const arr2: number[];
 const j = arr2[arr1[0]]; // should error
diff --git a/tests/cases/compiler/arrayOfSubtypeIsAssignableToReadonlyArray.ts b/tests/cases/compiler/arrayOfSubtypeIsAssignableToReadonlyArray.ts
@@ -1,3 +1,4 @@
+// @strict: false
 class A { a }
 class B extends A { b }
 class C<T> extends Array<T> { c }

diff --git a/tests/cases/compiler/arrowFunctionErrorSpan.ts b/tests/cases/compiler/arrowFunctionErrorSpan.ts
@@ -1,3 +1,4 @@
+// @strict: false
 function f(a: () => number) { }
 
 // oneliner