// REP-50. `-0.0` is a Float this language admits — ADR-045 orders it apart
// from `+0.0` inside a container — and ADR-083 requires a Float to render as
// text that reads back as the same Float.
//
// `1.0 / x` is the observation, because `==` cannot be: IEEE-754 says
// `-0.0 == 0.0`, so equality is blind to exactly the bit this is about.
// The value, computed. This was already right.
var computed = -1.0 * 0.0
out(computed)
out(1.0 / computed)
// The value, written. `-0.0` used to evaluate to `+0.0`, because a Float
// negation was lowered as `0.0 - x` and `0.0 - 0.0` is `+0.0`. So the two
// lines above printed `-0.0` / `-inf` and the two below printed `0.0` /
// `inf`: the rendering did not read back as the Float it named.
out(-0.0)
out(1.0 / (-0.0))
// Negation through a binding, which is the same lowering and the shape a
// constant-folding "fix" in the lexer would leave broken.
var zero = 0.0
out(-zero)
out(1.0 / (-zero))
// The other zero is still the other zero, and negation is an involution.
out(1.0 / 0.0)
out(1.0 / (-(-0.0)))
// Nothing about ordinary values changed.
out(-2.5)
out(0.0 - 2.5)