[Issue 20353] New: -checkaction=context does not work well with const numbers

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=20353

          Issue ID: 20353
           Summary: -checkaction=context does not work well with const
                    numbers
           Product: D
           Version: D2
          Hardware: x86_64
                OS: All
            Status: NEW
          Severity: normal
          Priority: P1
         Component: dmd
          Assignee: nobody at puremagic.com
          Reporter: dkorpel at live.nl

When compiling with -checkaction=context:
```D
void main() {
    const x = -1L;
    const y = -2L;
    assert(x == y);
}
```
expected: -1 != -2
actual: assert(x == y) failed

Also applies to floating points. I don't know why it fails to give context
here. Making either x or y mutable makes it work.

Also:

```D
void main() {
    const long[1] x = [uint.max];
    const long[1] y = [-1];
    assert(x == y);
}
```
expected: [4294967296] != [-1]
actual: [-1] != [-1]

This is because in core.internal.dassert: getPrintfFormat there is a check:
static if (is(T == long))
This doesn't Unqual T so it doesn't hold when T == const(long), so it chooses
the wrong format.

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