Function wrapping: use elementwise === for Expr equality

[fonsp]

Example:

x = 2.5

begin
	y = fill(0, 3)
	y[2] = x
	y
end

will give this error (which it should!)

InexactError: Int64(2.5)

    Int64@float.jl:710[inlined]
    convert@number.jl:7[inlined]
    setindex!@array.jl:847[inlined]
    top-level scope@Local: 3[inlined]

Now, changing the second cell to:

begin
	y = fill(0.0, 3)
	y[2] = x
	y
end

(0.0 instead of 0) should fix the error, but it doesn't, because 0 == 0.0 => the expressions are equal.

[fonsp]

or the hash