15.11 The checked and unchecked statements

The checked and unchecked statements are used to control the overflow
checking context for integraltype
arithmetic operations and conversions.
checked-statement:
checked block
unchecked-statement:
unchecked block
The checked statement causes all expressions in the block to be evaluated
in a checked context, and the
unchecked statement causes all expressions in the block to be evaluated in
an unchecked context.
The checked and unchecked statements are precisely equivalent to the
checked and unchecked
operators (§14.5.12), except that they operate on blocks instead of
expressions.