tests/cases/conformance/es6/destructuring/destructuringArrayBindingPatternAndAssignment2.ts(3,6): error TS2461: Type 'undefined' is not an array type. tests/cases/conformance/es6/destructuring/destructuringArrayBindingPatternAndAssignment2.ts(3,12): error TS2461: Type 'undefined' is not an array type. tests/cases/conformance/es6/destructuring/destructuringArrayBindingPatternAndAssignment2.ts(4,5): error TS2461: Type 'undefined' is not an array type. tests/cases/conformance/es6/destructuring/destructuringArrayBindingPatternAndAssignment2.ts(9,5): error TS2322: Type '[number, number, string]' is not assignable to type '[number, boolean, string]'. Types of property '1' are incompatible. Type 'number' is not assignable to type 'boolean'. tests/cases/conformance/es6/destructuring/destructuringArrayBindingPatternAndAssignment2.ts(17,6): error TS2322: Type 'string' is not assignable to type 'Number'. Property 'toFixed' is missing in type 'String'. tests/cases/conformance/es6/destructuring/destructuringArrayBindingPatternAndAssignment2.ts(22,5): error TS2322: Type 'number[]' is not assignable to type '[number, number]'. Property '0' is missing in type 'number[]'. tests/cases/conformance/es6/destructuring/destructuringArrayBindingPatternAndAssignment2.ts(23,5): error TS2322: Type 'number[]' is not assignable to type '[string, string]'. Property '0' is missing in type 'number[]'. tests/cases/conformance/es6/destructuring/destructuringArrayBindingPatternAndAssignment2.ts(34,5): error TS2461: Type 'F' is not an array type. ==== tests/cases/conformance/es6/destructuring/destructuringArrayBindingPatternAndAssignment2.ts (8 errors) ==== // V is an array assignment pattern, S is the type Any or an array-like type (section 3.3.2), and, for each assignment element E in V, // S is the type Any, or var [[a0], [[a1]]] = [] // Error ~~~~ !!! error TS2461: Type 'undefined' is not an array type. ~~~~~~ !!! error TS2461: Type 'undefined' is not an array type. var [[a2], [[a3]]] = undefined // Error ~~~~~~~~~~~~~~ !!! error TS2461: Type 'undefined' is not an array type. // V is an array assignment pattern, S is the type Any or an array-like type (section 3.3.2), and, for each assignment element E in V, // S is a tuple- like type (section 3.3.3) with a property named N of a type that is assignable to the target given in E, // where N is the numeric index of E in the array assignment pattern, or var [b0, b1, b2]: [number, boolean, string] = [1, 2, "string"]; // Error ~~~~~~~~~~~~ !!! error TS2322: Type '[number, number, string]' is not assignable to type '[number, boolean, string]'. !!! error TS2322: Types of property '1' are incompatible. !!! error TS2322: Type 'number' is not assignable to type 'boolean'. interface J extends Array { 2: number; } function bar(): J { return <[number, number, number]>[1, 2, 3]; } var [b3 = "string", b4, b5] = bar(); // Error ~~ !!! error TS2322: Type 'string' is not assignable to type 'Number'. !!! error TS2322: Property 'toFixed' is missing in type 'String'. // V is an array assignment pattern, S is the type Any or an array-like type (section 3.3.2), and, for each assignment element E in V, // S is not a tuple- like type and the numeric index signature type of S is assignable to the target given in E. var temp = [1, 2, 3] var [c0, c1]: [number, number] = [...temp]; // Error ~~~~~~~~ !!! error TS2322: Type 'number[]' is not assignable to type '[number, number]'. !!! error TS2322: Property '0' is missing in type 'number[]'. var [c2, c3]: [string, string] = [...temp]; // Error ~~~~~~~~ !!! error TS2322: Type 'number[]' is not assignable to type '[string, string]'. !!! error TS2322: Property '0' is missing in type 'number[]'. interface F { [idx: number]: boolean } function foo(idx: number): F { return { 2: true } } var [c4, c5, c6] = foo(1); // Error ~~~~~~~~~~~~ !!! error TS2461: Type 'F' is not an array type.