TypeScript Language Specification v1.5

the type Any.
In the example
function f({ a, b = "hello", c = 1 }) { ... }
the implied type of the binding pattern in the function's parameter is '{ a: any; b?: string; c?: number; }'.
Since the parameter has no type annotation, this becomes the type of the parameter.
In the example
var [a, b, c] = [1, "hello", true];
the array literal initializer expression is contextually typed by the implied type of the binding pattern,
specifically the tuple type '[any, any, any]'. Because the contextual type is a tuple type, the resulting type
of the array literal is the tuple type '[number, string, boolean]', and the destructuring declaration thus
gives the types number, string, and boolean to a, b, and c respectively.
5.2 If, Do, and While Statements
Expressions controlling 'if', 'do', and 'while' statements can be of any type (and not just type Boolean).
5.3 For Statements
Variable declarations in 'for' statements are extended in the same manner as variable declarations in
variable statements (section 5.1).
5.4 For-In Statements
In a 'for-in' statement of the form
for (v in expr) statement
v must be an expression classified as a reference of type Any or the String primitive type, and expr must
be an expression of type Any, an object type, or a type parameter type.
In a 'for-in' statement of the form
for (var v in expr) statement
v must be a variable declaration without a type annotation that declares a variable of type Any, and expr
must be an expression of type Any, an object type, or a type parameter type.
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