min const fn checks don't check set discriminant target

[oli-obk]

Leaving this issue as a reminder for https://github.com/rust-lang/rust/pull/66507/files#r347252249

It should be as simple as adding a check_place call to the SetDiscriminant

This issue has been assigned to @christianpoveda via this comment.

[ecstatic-morse]

This bug appears in check_consts::validation as well:

rust/src/librustc_mir/transform/check_consts/validation.rs

Lines 546 to 554 in 618b01f

	// FIXME(eddyb) should these really do nothing?
	StatementKind::FakeRead(..) |
	StatementKind::SetDiscriminant { .. } |
	StatementKind::StorageLive(_) |
	StatementKind::StorageDead(_) |
	StatementKind::InlineAsm {..} |
	StatementKind::Retag { .. } |
	StatementKind::AscribeUserType(..) |
	StatementKind::Nop => {}

Might as well stop letting inline ASM through to MIRI while you're at it.

[pvdrz]

I'm taking this one :P

[Dylan-DPC-zz]

@rustbot assign @christianpoveda