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detect and report shadows in nested bindings

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This commit is contained in:
Niko Matsakis 2012-05-21 09:37:22 -07:00
parent 1ad5f7d2c1
commit 8e73bb6ea0
2 changed files with 26 additions and 20 deletions
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41
src/rustc/middle/resolve.rs
View file

@ -681,28 +681,29 @@ fn visit_arm_with_scope(a: ast::arm, sc: scopes, v: vt<scopes>) {
// This is only for irrefutable patterns (e.g. ones that appear in a let)
// So if x occurs, and x is already known to be a enum, that's always an error
fn visit_local_with_scope(e: @env, loc: @local, sc:scopes, v:vt<scopes>) {
// Check whether the given local has the same name as a enum that's
// in scope
// We disallow this, in order to make alt patterns consisting of
// a single identifier unambiguous (does the pattern "foo" refer
// to enum foo, or is it binding a new name foo?)
alt loc.node.pat.node {
pat_ident(an_ident,_) {
alt lookup_in_scope(*e, sc, loc.span, path_to_ident(an_ident),
ns_val, false) {
some(ast::def_variant(enum_id,variant_id)) {
// Declaration shadows an enum that's in scope.
// That's an error.
e.sess.span_err(loc.span,
#fmt("declaration of `%s` shadows an \
enum that's in scope",
path_to_ident(an_ident)));
}
fn visit_local_with_scope(e: @env, loc: @local, &&sc: scopes, v:vt<scopes>) {
// Check whether the given local has the same name as a enum that's in
// scope. We disallow this, in order to make alt patterns consisting of a
// single identifier unambiguous (does the pattern "foo" refer to enum
// foo, or is it binding a new name foo?)
pat_util::walk_pat(loc.node.pat) { |p|
alt p.node {
pat_ident(path, _) {
alt lookup_in_scope(*e, sc, loc.span, path_to_ident(path),
ns_val, false) {
some(ast::def_variant(enum_id, variant_id)) {
// Declaration shadows an enum that's in scope.
// That's an error.
e.sess.span_err(loc.span,
#fmt("declaration of `%s` shadows an \
enum that's in scope",
path_to_ident(path)));
}
_ {}
}
}
}
_ {}
_ {}
}
}
visit::visit_local(loc, sc, v);
}

5
src/test/compile-fail/pat-shadow-in-nested-binding.rs Normal file
View file

@ -0,0 +1,5 @@
enum foo = uint;
fn main() {
let (foo, _) = (2, 3); //! ERROR declaration of `foo` shadows an enum that's in scope
}