Self::EnumVariant not considered const fn #64247
Description
When using Self to create an enum variant in Rust 1.37+, we get an error:
const VAL: Self = Self::X(42);
results in:
error: `Foo::X` is not yet stable as a const fn
but if the enum is constructed explicitly, the compilation succeeds:
const VAL: Self = Foo::X(42)
Looking at #53555, it looks like Self::EnumVariant should be considered a const fn with min_const_fn.