tests/cases/compiler/indexSignatureMustHaveTypeAnnotation.ts(3,5): error TS1169: A computed property name in an interface must directly refer to a built-in symbol. tests/cases/compiler/indexSignatureMustHaveTypeAnnotation.ts(3,6): error TS2304: Cannot find name 'x'. tests/cases/compiler/indexSignatureMustHaveTypeAnnotation.ts(4,5): error TS1021: An index signature must have a type annotation. tests/cases/compiler/indexSignatureMustHaveTypeAnnotation.ts(9,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol. tests/cases/compiler/indexSignatureMustHaveTypeAnnotation.ts(9,6): error TS2304: Cannot find name 'x'. tests/cases/compiler/indexSignatureMustHaveTypeAnnotation.ts(14,5): error TS1021: An index signature must have a type annotation. ==== tests/cases/compiler/indexSignatureMustHaveTypeAnnotation.ts (6 errors) ==== interface I { // Used to be indexer, now it is a computed property [x]: string; ~~~ !!! error TS1169: A computed property name in an interface must directly refer to a built-in symbol. ~ !!! error TS2304: Cannot find name 'x'. [x: string]; ~~~~~~~~~~~~ !!! error TS1021: An index signature must have a type annotation. } class C { // Used to be indexer, now it is a computed property [x]: string ~~~ !!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol. ~ !!! error TS2304: Cannot find name 'x'. } class C2 { [x: string] ~~~~~~~~~~~ !!! error TS1021: An index signature must have a type annotation. }