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Auto merge of #30295 - jseyfried:fix_extern_crate_duplicate, r=nrc

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Fix a bug allowing an item and an external crate to collide so long as the external crate is declared after the item. For example,
```rust
mod core { pub fn f() {} } // This would be an error if it followed the `extern crate`
extern crate core; // This declaration is shadowed by the preceding module

fn main() { core::f(); }
```
This is a [breaking-change], but it looks unlikely to cause breakage in practice, and any breakage can be fixed by removing colliding `extern crate` declarations, which are shadowed and hence unused.
This commit is contained in:
bors 2016-01-11 06:40:58 +00:00
commit 69e1f57dfb
2 changed files with 22 additions and 13 deletions
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2
src/librustc_resolve/build_reduced_graph.rs
View File

@ -325,7 +325,7 @@ impl<'a, 'b:'a, 'tcx:'b> GraphBuilder<'a, 'b, 'tcx> {
debug!("(build reduced graph for item) found extern `{}`",
module_to_string(&*external_module));
self.check_for_conflicts_between_external_crates(&**parent, name, sp);
self.check_for_conflicts_for_external_crate(&parent, name, sp);
parent.external_module_children
.borrow_mut()
.insert(name, external_module.clone());

33
src/librustc_resolve/lib.rs
View File

@ -122,6 +122,8 @@ enum SuggestionType {
}
pub enum ResolutionError<'a> {
/// error E0260: name conflicts with an extern crate
NameConflictsWithExternCrate(Name),
/// error E0401: can't use type parameters from outer function
TypeParametersFromOuterFunction,
/// error E0402: cannot use an outer type parameter in this context
@ -228,6 +230,14 @@ fn resolve_struct_error<'b, 'a: 'b, 'tcx: 'a>(resolver: &'b Resolver<'a, 'tcx>,
}
match resolution_error {
ResolutionError::NameConflictsWithExternCrate(name) => {
struct_span_err!(resolver.session,
span,
E0260,
"the name `{}` conflicts with an external crate \
that has been imported into this module",
name)
}
ResolutionError::TypeParametersFromOuterFunction => {
struct_span_err!(resolver.session,
span,
@ -1297,12 +1307,8 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
}
}
/// Checks that the names of external crates don't collide with other
/// external crates.
fn check_for_conflicts_between_external_crates(&self,
module: &Module,
name: Name,
span: Span) {
/// Check that an external crate doesn't collide with items or other external crates.
fn check_for_conflicts_for_external_crate(&self, module: &Module, name: Name, span: Span) {
if module.external_module_children.borrow().contains_key(&name) {
span_err!(self.session,
span,
@ -1310,6 +1316,14 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
"an external crate named `{}` has already been imported into this module",
name);
}
match module.children.borrow().get(&name) {
Some(name_bindings) if name_bindings.type_ns.defined() => {
resolve_error(self,
name_bindings.type_ns.span().unwrap_or(codemap::DUMMY_SP),
ResolutionError::NameConflictsWithExternCrate(name));
}
_ => {},
}
}
/// Checks that the names of items don't collide with external crates.
@ -1318,12 +1332,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
name: Name,
span: Span) {
if module.external_module_children.borrow().contains_key(&name) {
span_err!(self.session,
span,
E0260,
"the name `{}` conflicts with an external crate that has been imported \
into this module",
name);
resolve_error(self, span, ResolutionError::NameConflictsWithExternCrate(name));
}
}