Pushing used suppresses the XDeclaredButNotUsed hint for some identifiers, but not others

[ee7]

Example

{.push used.}
const a = 42
proc b = echo "hi"
{.pop.}

Current behavior

The compiler outputs an XDeclaredButNotUsed hint for a (but not b):

/tmp/used.nim(2, 7) Hint: 'a' is declared but not used [XDeclaredButNotUsed]

Expected behavior

No such hint for a or b.

Nim Version

Nim 2.0.0 and devel (57ffeaf).

Additional Information

The below works as expected, to suppress both hints:

const a {.used.} = 42
proc b {.used.} = echo "hi"

Issue #4044 was closed 5 years ago, citing the above workaround for

{.push hint[XDeclaredButNotUsed]: off.}
const a = 42
proc b = echo "hi"
{.pop.}

which still produces the XDeclaredButNotUsed hint for both a and b.

The issue in the example was reported in the #main channel.

[ringabout]

It's a subtle bug. I discovered it yesterday in #22913.

{.push used.}
let a {.deprecated.} = 42
proc b = echo "hi"
{.pop.}

Somehow for var/let/const sections, it needs a pre-existing pragma to make push in effect. Let me investigate it later.

[ringabout]

Yeah, the reason is that implicitPragmas is not applied to Identifiers withouu pragmas.