bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Fix redundant import errors for preload extern crate

Browse source
This commit is contained in:
yukang 2024-03-04 10:24:23 +08:00
parent 62415e2a95
commit 5a4ff2779e
10 changed files with 230 additions and 72 deletions
Download patch file Download diff file Expand all files Collapse all files

146
compiler/rustc_resolve/src/check_unused.rs
View file

@ -137,6 +137,81 @@ impl<'a, 'b, 'tcx> UnusedImportCheckVisitor<'a, 'b, 'tcx> {
self.check_import_as_underscore(item, *id);
}
}
fn report_unused_extern_crate_items(
&mut self,
maybe_unused_extern_crates: FxHashMap<ast::NodeId, Span>,
) {
let tcx = self.r.tcx();
for extern_crate in &self.extern_crate_items {
let warn_if_unused = !extern_crate.ident.name.as_str().starts_with('_');
// If the crate is fully unused, we suggest removing it altogether.
// We do this in any edition.
if warn_if_unused {
if let Some(&span) = maybe_unused_extern_crates.get(&extern_crate.id) {
self.r.lint_buffer.buffer_lint_with_diagnostic(
UNUSED_EXTERN_CRATES,
extern_crate.id,
span,
"unused extern crate",
BuiltinLintDiag::UnusedExternCrate {
removal_span: extern_crate.span_with_attributes,
},
);
continue;
}
}
// If we are not in Rust 2018 edition, then we don't make any further
// suggestions.
if !tcx.sess.at_least_rust_2018() {
continue;
}
// If the extern crate has any attributes, they may have funky
// semantics we can't faithfully represent using `use` (most
// notably `#[macro_use]`). Ignore it.
if extern_crate.has_attrs {
continue;
}
// If the extern crate is renamed, then we cannot suggest replacing it with a use as this
// would not insert the new name into the prelude, where other imports in the crate may be
// expecting it.
if extern_crate.renames {
continue;
}
// If the extern crate isn't in the extern prelude,
// there is no way it can be written as a `use`.
if !self
.r
.extern_prelude
.get(&extern_crate.ident)
.is_some_and(|entry| !entry.introduced_by_item)
{
continue;
}
let vis_span = extern_crate
.vis_span
.find_ancestor_inside(extern_crate.span)
.unwrap_or(extern_crate.vis_span);
let ident_span = extern_crate
.ident
.span
.find_ancestor_inside(extern_crate.span)
.unwrap_or(extern_crate.ident.span);
self.r.lint_buffer.buffer_lint_with_diagnostic(
UNUSED_EXTERN_CRATES,
extern_crate.id,
extern_crate.span,
"`extern crate` is not idiomatic in the new edition",
BuiltinLintDiag::ExternCrateNotIdiomatic { vis_span, ident_span },
);
}
}
}
impl<'a, 'b, 'tcx> Visitor<'a> for UnusedImportCheckVisitor<'a, 'b, 'tcx> {
@ -335,6 +410,8 @@ impl Resolver<'_, '_> {
};
visit::walk_crate(&mut visitor, krate);
visitor.report_unused_extern_crate_items(maybe_unused_extern_crates);
for unused in visitor.unused_imports.values() {
let mut fixes = Vec::new();
let spans = match calc_unused_spans(unused, &unused.use_tree, unused.use_tree_id) {
@ -416,75 +493,6 @@ impl Resolver<'_, '_> {
);
}
for extern_crate in visitor.extern_crate_items {
let warn_if_unused = !extern_crate.ident.name.as_str().starts_with('_');
// If the crate is fully unused, we suggest removing it altogether.
// We do this in any edition.
if warn_if_unused {
if let Some(&span) = maybe_unused_extern_crates.get(&extern_crate.id) {
visitor.r.lint_buffer.buffer_lint_with_diagnostic(
UNUSED_EXTERN_CRATES,
extern_crate.id,
span,
"unused extern crate",
BuiltinLintDiag::UnusedExternCrate {
removal_span: extern_crate.span_with_attributes,
},
);
continue;
}
}
// If we are not in Rust 2018 edition, then we don't make any further
// suggestions.
if !tcx.sess.at_least_rust_2018() {
continue;
}
// If the extern crate has any attributes, they may have funky
// semantics we can't faithfully represent using `use` (most
// notably `#[macro_use]`). Ignore it.
if extern_crate.has_attrs {
continue;
}
// If the extern crate is renamed, then we cannot suggest replacing it with a use as this
// would not insert the new name into the prelude, where other imports in the crate may be
// expecting it.
if extern_crate.renames {
continue;
}
// If the extern crate isn't in the extern prelude,
// there is no way it can be written as a `use`.
if !visitor
.r
.extern_prelude
.get(&extern_crate.ident)
.is_some_and(|entry| !entry.introduced_by_item)
{
continue;
}
let vis_span = extern_crate
.vis_span
.find_ancestor_inside(extern_crate.span)
.unwrap_or(extern_crate.vis_span);
let ident_span = extern_crate
.ident
.span
.find_ancestor_inside(extern_crate.span)
.unwrap_or(extern_crate.ident.span);
visitor.r.lint_buffer.buffer_lint_with_diagnostic(
UNUSED_EXTERN_CRATES,
extern_crate.id,
extern_crate.span,
"`extern crate` is not idiomatic in the new edition",
BuiltinLintDiag::ExternCrateNotIdiomatic { vis_span, ident_span },
);
}
let unused_imports = visitor.unused_imports;
let mut check_redundant_imports = FxIndexSet::default();
for module in self.arenas.local_modules().iter() {