Deduce that a name resolution fails (as opposed to being indeterminte) in more cases.

Author: jseyfried

src/librustc_resolve/resolve_imports.rs

@@ -155,6 +155,9 @@ impl<'a> NameResolution<'a> {
     fn result(&self, allow_private_imports: bool) -> ResolveResult<&'a NameBinding<'a>> {
         match self.binding {
             Some(binding) if !binding.defined_with(DefModifiers::GLOB_IMPORTED) => Success(binding),
+            // If we don't allow private imports and no public imports can define the name, fail.
+            _ if !allow_private_imports && self.pub_outstanding_references == 0 &&
+                 !self.binding.map(NameBinding::is_public).unwrap_or(false) => Failed(None),
             _ if self.outstanding_references > 0 => Indeterminate,
             Some(binding) => Success(binding),
             None => Failed(None),