--expand-macros (prettyPrint) gives wrong output for unary operators as the required parentheses are removed resulting in wrong not parseable pretty printed specification. Both the untyped and typed ASTs are correct. The following example shows the original correct test input:

function A -> Bits<32> =  -4 as Bits<32>
function B -> Bits<32> = -(4 as Bits<32>)
function C -> Bits<32> = ~(3 as Bits<32>)
function D -> Bool     = !(3 as Bool)

Here is the wrong prettyPrint output where the parentheses are missing:

function A -> Bits<32> = -4 as Bits<32>
function B -> Bits<32> = -4 as Bits<32>
function C -> Bits<32> = ~3 as Bits<32>
function D -> Bool = !3 as Bool

The output for A is correct, all the others are wrong.
The code in Expr.java in lines 462 to 468 is wrong.
The following must be deleted (and the closing }:

    if (operator instanceof UnOp) {
      operand.prettyPrint(indent, builder);
    } else {

Please fix that soon, I need to check the AArch64 spec.Expr.java is easy, the tests could be some work.