diff --git a/tests/cases/fourslash/completionEntryForUnionMethod.ts b/tests/cases/fourslash/completionEntryForUnionMethod.ts
index f8fd9ad9dc9..81c839e7150 100644
--- a/tests/cases/fourslash/completionEntryForUnionMethod.ts
+++ b/tests/cases/fourslash/completionEntryForUnionMethod.ts
@@ -5,7 +5,7 @@
 
 goTo.marker();
 verify.quickInfoIs(
-    "(property) map: (<U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => U[]) | (<U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => U[])",
+    "(property) map: (<U>(this: readonly, callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => U[]) | (<U>(this: readonly, callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => U[])",
     "Calls a defined callback function on each element of an array, and returns an array that contains the results.");
 
-verify.completionListContains('map', "(property) map: (<U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => U[]) | (<U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => U[])");
\ No newline at end of file
+verify.completionListContains('map', "(property) map: (<U>(this: readonly, callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => U[]) | (<U>(this: readonly, callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => U[])");
\ No newline at end of file
diff --git a/tests/cases/fourslash/completionListOfGnericSymbol.ts b/tests/cases/fourslash/completionListOfGnericSymbol.ts
index 9251892db23..701add1dfdb 100644
--- a/tests/cases/fourslash/completionListOfGnericSymbol.ts
+++ b/tests/cases/fourslash/completionListOfGnericSymbol.ts
@@ -7,5 +7,5 @@
 
 goTo.marker();
 verify.completionListContains('length', "(property) Array<number>.length: number", /*docComments*/ undefined, /*kind*/ "property");
-verify.completionListContains('toString', "(method) Array<number>.toString(): string", /*docComments*/ undefined, /*kind*/ "method");
+verify.completionListContains('toString', "(method) Array<number>.toString(this: readonly): string", /*docComments*/ undefined, /*kind*/ "method");