TypeScript Language Specification v1.5

A spread element must specify an expression of an array-like type (section 3.3.2), or otherwise an error
occurs.
The rules above mean that an array literal is always of an array type, unless it is contextually typed by a
tuple-like type. For example
var a = [1, 2];
// number[]
var b = ["hello", true];
// (string | boolean)[]
var c: [number, string] = [3, "three"]; // [number, string]
When the output target is ECMAScript 3 or 5, array literals containing spread elements are rewritten to
invocations of the concat method. For example, the assignments
var a = [2, 3, 4];
var b = [0, 1, ...a, 5, 6];
are rewritten to
var a = [2, 3, 4];
var b = [0, 1].concat(a, [5, 6]);
4.7 Parentheses
A parenthesized expression
( expr )
has the same type and classification as the contained expression itself. Specifically, if the contained
expression is classified as a reference, so is the parenthesized expression.
4.8 The super Keyword
The super keyword can be used in expressions to reference base class properties and the base class
constructor.
CallExpression: ( Modified )
…
super ( ArgumentList opt )
super . IdentifierName
4.8.1 Super Calls
Super calls consist of the keyword super followed by an argument list enclosed in parentheses. Super calls
are only permitted in constructors of derived classes, as described in section 8.3.2.
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