rustc_resolve: move unused import checking into its own module.
This commit is contained in:
Eduard Burtescu
parent
c54fc980f3
commit
1614d92f51
161
src/librustc_resolve/check_unused.rs
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161
src/librustc_resolve/check_unused.rs
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@ -0,0 +1,161 @@
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// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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//
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// Unused import checking
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//
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// Although this is mostly a lint pass, it lives in here because it depends on
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// resolve data structures and because it finalises the privacy information for
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// `use` directives.
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//
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use Resolver;
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use Namespace::{TypeNS, ValueNS};
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use rustc::lint;
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use rustc::middle::privacy::{DependsOn, LastImport, Used, Unused};
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use syntax::ast;
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use syntax::ast::{ViewItem, ViewItemExternCrate, ViewItemUse};
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use syntax::ast::{ViewPathGlob, ViewPathList, ViewPathSimple};
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use syntax::codemap::{Span, DUMMY_SP};
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use syntax::visit::{mod, Visitor};
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struct UnusedImportCheckVisitor<'a, 'b:'a> {
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resolver: &'a mut Resolver<'b>
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}
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// Deref and DerefMut impls allow treating UnusedImportCheckVisitor as Resolver.
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impl<'a, 'b> Deref<Resolver<'b>> for UnusedImportCheckVisitor<'a, 'b> {
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fn deref<'c>(&'c self) -> &'c Resolver<'b> {
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&*self.resolver
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}
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}
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impl<'a, 'b> DerefMut<Resolver<'b>> for UnusedImportCheckVisitor<'a, 'b> {
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fn deref_mut<'c>(&'c mut self) -> &'c mut Resolver<'b> {
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&mut *self.resolver
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}
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}
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impl<'a, 'b> UnusedImportCheckVisitor<'a, 'b> {
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// We have information about whether `use` (import) directives are actually used now.
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// If an import is not used at all, we signal a lint error. If an import is only used
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// for a single namespace, we remove the other namespace from the recorded privacy
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// information. That means in privacy.rs, we will only check imports and namespaces
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// which are used. In particular, this means that if an import could name either a
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// public or private item, we will check the correct thing, dependent on how the import
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// is used.
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fn finalize_import(&mut self, id: ast::NodeId, span: Span) {
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debug!("finalizing import uses for {}",
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self.session.codemap().span_to_snippet(span));
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if !self.used_imports.contains(&(id, TypeNS)) &&
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!self.used_imports.contains(&(id, ValueNS)) {
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self.session.add_lint(lint::builtin::UNUSED_IMPORTS,
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id,
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span,
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"unused import".to_string());
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}
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let (v_priv, t_priv) = match self.last_private.get(&id) {
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Some(&LastImport {
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value_priv: v,
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value_used: _,
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type_priv: t,
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type_used: _
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}) => (v, t),
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Some(_) => {
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panic!("we should only have LastImport for `use` directives")
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}
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_ => return,
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};
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let mut v_used = if self.used_imports.contains(&(id, ValueNS)) {
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Used
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} else {
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Unused
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};
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let t_used = if self.used_imports.contains(&(id, TypeNS)) {
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Used
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} else {
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Unused
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};
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match (v_priv, t_priv) {
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// Since some items may be both in the value _and_ type namespaces (e.g., structs)
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// we might have two LastPrivates pointing at the same thing. There is no point
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// checking both, so lets not check the value one.
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(Some(DependsOn(def_v)), Some(DependsOn(def_t))) if def_v == def_t => v_used = Unused,
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_ => {},
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}
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self.last_private.insert(id, LastImport{value_priv: v_priv,
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value_used: v_used,
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type_priv: t_priv,
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type_used: t_used});
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}
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}
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impl<'a, 'b, 'v> Visitor<'v> for UnusedImportCheckVisitor<'a, 'b> {
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fn visit_view_item(&mut self, vi: &ViewItem) {
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// Ignore is_public import statements because there's no way to be sure
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// whether they're used or not. Also ignore imports with a dummy span
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// because this means that they were generated in some fashion by the
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// compiler and we don't need to consider them.
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if vi.vis == ast::Public || vi.span == DUMMY_SP {
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visit::walk_view_item(self, vi);
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return;
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}
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match vi.node {
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ViewItemExternCrate(_, _, id) => {
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if let Some(crate_num) = self.session.cstore.find_extern_mod_stmt_cnum(id) {
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if !self.used_crates.contains(&crate_num) {
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self.session.add_lint(lint::builtin::UNUSED_EXTERN_CRATES,
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id,
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vi.span,
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"unused extern crate".to_string());
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}
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}
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},
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ViewItemUse(ref p) => {
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match p.node {
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ViewPathSimple(_, _, id) => {
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self.finalize_import(id, p.span)
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}
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ViewPathList(_, ref list, _) => {
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for i in list.iter() {
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self.finalize_import(i.node.id(), i.span);
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}
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}
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ViewPathGlob(_, id) => {
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if !self.used_imports.contains(&(id, TypeNS)) &&
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!self.used_imports.contains(&(id, ValueNS)) {
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self.session
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.add_lint(lint::builtin::UNUSED_IMPORTS,
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id,
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p.span,
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"unused import".to_string());
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}
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}
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}
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}
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}
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visit::walk_view_item(self, vi);
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}
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}
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pub fn check_crate(resolver: &mut Resolver, krate: &ast::Crate) {
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let mut visitor = UnusedImportCheckVisitor { resolver: resolver };
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visit::walk_crate(&mut visitor, krate);
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}
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@ -96,6 +96,8 @@ use std::mem::replace;
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use std::rc::{Rc, Weak};
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use std::uint;
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mod check_unused;
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#[deriving(Copy)]
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struct BindingInfo {
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span: Span,
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@ -935,17 +937,6 @@ impl<'a, 'b, 'v> Visitor<'v> for BuildReducedGraphVisitor<'a, 'b> {
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}
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struct UnusedImportCheckVisitor<'a, 'b:'a> {
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resolver: &'a mut Resolver<'b>
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}
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impl<'a, 'b, 'v> Visitor<'v> for UnusedImportCheckVisitor<'a, 'b> {
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fn visit_view_item(&mut self, vi: &ViewItem) {
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self.resolver.check_for_item_unused_imports(vi);
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visit::walk_view_item(self, vi);
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}
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}
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#[deriving(PartialEq)]
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enum FallbackChecks {
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Everything,
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@ -1006,22 +997,6 @@ impl<'a> Resolver<'a> {
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emit_errors: true,
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}
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}
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/// The main name resolution procedure.
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fn resolve(&mut self, krate: &ast::Crate) {
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self.build_reduced_graph(krate);
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self.session.abort_if_errors();
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self.resolve_imports();
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self.session.abort_if_errors();
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self.record_exports();
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self.session.abort_if_errors();
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self.resolve_crate(krate);
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self.session.abort_if_errors();
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self.check_for_unused_imports(krate);
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}
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//
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// Reduced graph building
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@ -6068,119 +6043,6 @@ impl<'a> Resolver<'a> {
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}
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}
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//
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// Unused import checking
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//
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// Although this is mostly a lint pass, it lives in here because it depends on
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// resolve data structures and because it finalises the privacy information for
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// `use` directives.
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//
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fn check_for_unused_imports(&mut self, krate: &ast::Crate) {
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let mut visitor = UnusedImportCheckVisitor{ resolver: self };
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visit::walk_crate(&mut visitor, krate);
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}
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fn check_for_item_unused_imports(&mut self, vi: &ViewItem) {
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// Ignore is_public import statements because there's no way to be sure
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// whether they're used or not. Also ignore imports with a dummy span
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// because this means that they were generated in some fashion by the
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// compiler and we don't need to consider them.
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if vi.vis == Public { return }
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if vi.span == DUMMY_SP { return }
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match vi.node {
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ViewItemExternCrate(_, _, id) => {
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if let Some(crate_num) = self.session.cstore.find_extern_mod_stmt_cnum(id) {
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if !self.used_crates.contains(&crate_num) {
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self.session.add_lint(lint::builtin::UNUSED_EXTERN_CRATES,
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id,
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vi.span,
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"unused extern crate".to_string());
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}
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}
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},
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ViewItemUse(ref p) => {
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match p.node {
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ViewPathSimple(_, _, id) => self.finalize_import(id, p.span),
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ViewPathList(_, ref list, _) => {
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for i in list.iter() {
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self.finalize_import(i.node.id(), i.span);
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}
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},
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ViewPathGlob(_, id) => {
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if !self.used_imports.contains(&(id, TypeNS)) &&
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!self.used_imports.contains(&(id, ValueNS)) {
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self.session
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.add_lint(lint::builtin::UNUSED_IMPORTS,
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id,
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p.span,
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"unused import".to_string());
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}
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},
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}
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}
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}
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}
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// We have information about whether `use` (import) directives are actually used now.
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// If an import is not used at all, we signal a lint error. If an import is only used
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// for a single namespace, we remove the other namespace from the recorded privacy
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// information. That means in privacy.rs, we will only check imports and namespaces
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// which are used. In particular, this means that if an import could name either a
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// public or private item, we will check the correct thing, dependent on how the import
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// is used.
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fn finalize_import(&mut self, id: NodeId, span: Span) {
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debug!("finalizing import uses for {}",
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self.session.codemap().span_to_snippet(span));
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if !self.used_imports.contains(&(id, TypeNS)) &&
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!self.used_imports.contains(&(id, ValueNS)) {
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self.session.add_lint(lint::builtin::UNUSED_IMPORTS,
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id,
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span,
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"unused import".to_string());
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}
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let (v_priv, t_priv) = match self.last_private.get(&id) {
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Some(&LastImport {
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value_priv: v,
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value_used: _,
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type_priv: t,
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type_used: _
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}) => (v, t),
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Some(_) => {
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panic!("we should only have LastImport for `use` directives")
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}
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_ => return,
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};
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let mut v_used = if self.used_imports.contains(&(id, ValueNS)) {
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Used
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} else {
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Unused
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};
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let t_used = if self.used_imports.contains(&(id, TypeNS)) {
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Used
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} else {
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Unused
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};
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match (v_priv, t_priv) {
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// Since some items may be both in the value _and_ type namespaces (e.g., structs)
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// we might have two LastPrivates pointing at the same thing. There is no point
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// checking both, so lets not check the value one.
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(Some(DependsOn(def_v)), Some(DependsOn(def_t))) if def_v == def_t => v_used = Unused,
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_ => {},
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}
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self.last_private.insert(id, LastImport{value_priv: v_priv,
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value_used: v_used,
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type_priv: t_priv,
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type_used: t_used});
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}
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//
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// Diagnostics
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//
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@ -6268,7 +6130,21 @@ pub fn resolve_crate(session: &Session,
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krate: &Crate)
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-> CrateMap {
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let mut resolver = Resolver::new(session, krate.span);
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resolver.resolve(krate);
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resolver.build_reduced_graph(krate);
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session.abort_if_errors();
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resolver.resolve_imports();
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session.abort_if_errors();
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resolver.record_exports();
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session.abort_if_errors();
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resolver.resolve_crate(krate);
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session.abort_if_errors();
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check_unused::check_crate(&mut resolver, krate);
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CrateMap {
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def_map: resolver.def_map,
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freevars: resolver.freevars,
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