SpanExt name collision with proc_macro2

[bart358]

SpanExt defines a method:

fn end(&self) -> Span;

And implements it on Span. However, proc-marco2 with feature span-locations also defines a method on Span:

    #[cfg(span_locations)]
    #[cfg_attr(doc_cfg, doc(cfg(feature = "span-locations")))]
    pub fn end(&self) -> LineColumn {
        self.inner.end()
    }

When calling end on a Span object with that feature enabled the above method takes precedence. This breaks code in an ast module where it defines:

diag = diag.span_error(v.span().end(), "missing discriminant");

Since the SpanExt is in scope the intention was for .end() to return a Span object which works since it implements MultiSpan required by span_error. With span-locations enabled It returns a LineColumn which does not implement MultiSpan:

   --> int-enum-1.0.0/src/ast.rs:120:36
    |
120 |             diag = diag.span_error(v.span().end(), "missing discriminant");
    |                         ---------- ^^^^^^^^^^^^^^ the trait `proc_macro2_diagnostics::diagnostic::MultiSpan` is not implemented for `LineColumn`
    |                         |
    |                         required by a bound introduced by this call
    |
    = help: the following other types implement trait `proc_macro2_diagnostics::diagnostic::MultiSpan`:
              proc_macro2::Span
              Vec<proc_macro2::Span>
              &'a [proc_macro2::Span]
note: required by a bound in `proc_macro2_diagnostics::Diagnostic::span_error`

The solution would be to refer to the trait explicitly:

diag = diag.span_error(<Span as SpanExt>::end(&v.span()), "missing discriminant");

[Juici]

I just noticed the build errors, I'll fix it.

[Juici]

This should be fixed by #15 for version 1.0.1.