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rework to report errors from crates in a consistent order

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We first collect unused crates into a map and then walk all extern
crates in crate order.
This commit is contained in:
Niko Matsakis 2018-05-29 11:31:34 -04:00
parent 8b39808ffe
commit b37cc851e6
3 changed files with 74 additions and 82 deletions
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90
src/librustc_typeck/check_unused.rs
View File

@ -120,62 +120,68 @@ fn unused_crates_lint<'tcx>(tcx: TyCtxt<'_, 'tcx, 'tcx>) {
.cloned()
.collect();
// Issue lints for fully unused crates that suggest removing them.
for (&def_id, &span) in &unused_extern_crates {
assert_eq!(def_id.krate, LOCAL_CRATE);
let hir_id = tcx.hir.definitions().def_index_to_hir_id(def_id.index);
let id = tcx.hir.hir_to_node_id(hir_id);
let msg = "unused extern crate";
tcx.struct_span_lint_node(lint, id, span, msg)
.span_suggestion_short(span, "remove it", "".to_string())
.emit();
}
// If we are not in Rust 2018 edition, we are done.
if !tcx.sess.rust_2018() {
return;
}
// Otherwise, we can *also* suggest rewriting `extern crate`
// into `use` etc.
let mut crates_to_convert_to_use = vec![];
// Collect all the extern crates (in a reliable order).
let mut crates_to_lint = vec![];
tcx.hir.krate().visit_all_item_likes(&mut CollectExternCrateVisitor {
tcx,
unused_extern_crates: &unused_extern_crates,
crates_to_convert_to_use: &mut crates_to_convert_to_use,
crates_to_lint: &mut crates_to_lint,
});
for to_convert in &crates_to_convert_to_use {
assert_eq!(to_convert.def_id.krate, LOCAL_CRATE);
let hir_id = tcx.hir.definitions().def_index_to_hir_id(to_convert.def_id.index);
for extern_crate in &crates_to_lint {
assert!(extern_crate.def_id.is_local());
// If the crate is fully unused, we suggest removing it altogether.
// We do this in any edition.
if let Some(&span) = unused_extern_crates.get(&extern_crate.def_id) {
assert_eq!(extern_crate.def_id.krate, LOCAL_CRATE);
let hir_id = tcx.hir.definitions().def_index_to_hir_id(extern_crate.def_id.index);
let id = tcx.hir.hir_to_node_id(hir_id);
let msg = "unused extern crate";
tcx.struct_span_lint_node(lint, id, span, msg)
.span_suggestion_short(span, "remove it", "".to_string())
.emit();
continue;
}
// If we are not in Rust 2018 edition, then we don't make any further
// suggestions.
if !tcx.sess.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 !tcx.get_attrs(extern_crate.def_id).is_empty() {
continue;
}
// Otherwise, we can convert it into a `use` of some kind.
let hir_id = tcx.hir.definitions().def_index_to_hir_id(extern_crate.def_id.index);
let id = tcx.hir.hir_to_node_id(hir_id);
let item = tcx.hir.expect_item(id);
let msg = "`extern crate` is not idiomatic in the new edition";
let help = format!(
"convert it to a `{}`",
visibility_qualified(&item.vis, "use")
);
let base_replacement = match to_convert.orig_name {
let base_replacement = match extern_crate.orig_name {
Some(orig_name) => format!("use {} as {};", orig_name, item.name),
None => format!("use {};", item.name),
};
let replacement = visibility_qualified(&item.vis, &base_replacement);
tcx.struct_span_lint_node(lint, id, to_convert.span, msg)
.span_suggestion_short(to_convert.span, &help, replacement)
tcx.struct_span_lint_node(lint, id, extern_crate.span, msg)
.span_suggestion_short(extern_crate.span, &help, replacement)
.emit();
}
}
struct CollectExternCrateVisitor<'a, 'tcx: 'a> {
tcx: TyCtxt<'a, 'tcx, 'tcx>,
unused_extern_crates: &'a FxHashMap<DefId, Span>,
crates_to_convert_to_use: &'a mut Vec<ExternCrateToConvertToUse>,
crates_to_lint: &'a mut Vec<ExternCrateToLint>,
}
struct ExternCrateToConvertToUse {
struct ExternCrateToLint {
/// def-id of the extern crate
def_id: DefId,
@ -192,22 +198,8 @@ impl<'a, 'tcx, 'v> ItemLikeVisitor<'v> for CollectExternCrateVisitor<'a, 'tcx> {
fn visit_item(&mut self, item: &hir::Item) {
if let hir::ItemExternCrate(orig_name) = item.node {
let extern_crate_def_id = self.tcx.hir.local_def_id(item.id);
// If the crate is fully unused, we are going to suggest
// removing it anyway, so ignore it.
if self.unused_extern_crates.contains_key(&extern_crate_def_id) {
return;
}
// If the extern crate has any attributes, they may have funky
// semantics we can't entirely understand. Ignore it.
if !self.tcx.get_attrs(extern_crate_def_id).is_empty() {
return;
}
// Otherwise, we can convert it into a `use` of some kind.
self.crates_to_convert_to_use.push(
ExternCrateToConvertToUse {
self.crates_to_lint.push(
ExternCrateToLint {
def_id: extern_crate_def_id,
span: item.span,
orig_name,

54
src/test/ui-fulldeps/unnecessary-extern-crate.stderr
View File

@ -1,8 +1,8 @@
error: unused extern crate
--> $DIR/unnecessary-extern-crate.rs:51:5
--> $DIR/unnecessary-extern-crate.rs:16:1
|
LL | extern crate alloc;
| ^^^^^^^^^^^^^^^^^^^ help: remove it
LL | extern crate alloc;
| ^^^^^^^^^^^^^^^^^^^ help: remove it
|
note: lint level defined here
--> $DIR/unnecessary-extern-crate.rs:13:9
@ -16,30 +16,6 @@ error: unused extern crate
LL | extern crate alloc as x;
| ^^^^^^^^^^^^^^^^^^^^^^^^ help: remove it
error: unused extern crate
--> $DIR/unnecessary-extern-crate.rs:55:5
|
LL | extern crate alloc as x;
| ^^^^^^^^^^^^^^^^^^^^^^^^ help: remove it
error: unused extern crate
--> $DIR/unnecessary-extern-crate.rs:68:9
|
LL | extern crate alloc;
| ^^^^^^^^^^^^^^^^^^^ help: remove it
error: unused extern crate
--> $DIR/unnecessary-extern-crate.rs:16:1
|
LL | extern crate alloc;
| ^^^^^^^^^^^^^^^^^^^ help: remove it
error: unused extern crate
--> $DIR/unnecessary-extern-crate.rs:72:9
|
LL | extern crate alloc as x;
| ^^^^^^^^^^^^^^^^^^^^^^^^ help: remove it
error: `extern crate` is not idiomatic in the new edition
--> $DIR/unnecessary-extern-crate.rs:26:1
|
@ -76,6 +52,18 @@ error: `extern crate` is not idiomatic in the new edition
LL | pub(super) extern crate libc as d;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: convert it to a `pub(super) use`
error: unused extern crate
--> $DIR/unnecessary-extern-crate.rs:51:5
|
LL | extern crate alloc;
| ^^^^^^^^^^^^^^^^^^^ help: remove it
error: unused extern crate
--> $DIR/unnecessary-extern-crate.rs:55:5
|
LL | extern crate alloc as x;
| ^^^^^^^^^^^^^^^^^^^^^^^^ help: remove it
error: `extern crate` is not idiomatic in the new edition
--> $DIR/unnecessary-extern-crate.rs:59:5
|
@ -88,6 +76,18 @@ error: `extern crate` is not idiomatic in the new edition
LL | pub extern crate test as y;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: convert it to a `pub use`
error: unused extern crate
--> $DIR/unnecessary-extern-crate.rs:68:9
|
LL | extern crate alloc;
| ^^^^^^^^^^^^^^^^^^^ help: remove it
error: unused extern crate
--> $DIR/unnecessary-extern-crate.rs:72:9
|
LL | extern crate alloc as x;
| ^^^^^^^^^^^^^^^^^^^^^^^^ help: remove it
error: `extern crate` is not idiomatic in the new edition
--> $DIR/unnecessary-extern-crate.rs:76:9
|

12
src/test/ui/suggestions/removing-extern-crate.stderr
View File

@ -1,8 +1,8 @@
warning: unused extern crate
--> $DIR/removing-extern-crate.rs:24:5
--> $DIR/removing-extern-crate.rs:19:1
|
LL | extern crate std;
| ^^^^^^^^^^^^^^^^^ help: remove it
LL | extern crate std as foo;
| ^^^^^^^^^^^^^^^^^^^^^^^^ help: remove it
|
note: lint level defined here
--> $DIR/removing-extern-crate.rs:16:9
@ -24,8 +24,8 @@ LL | extern crate std as foo;
| ^^^^^^^^^^^^^^^^^^^^^^^^ help: remove it
warning: unused extern crate
--> $DIR/removing-extern-crate.rs:19:1
--> $DIR/removing-extern-crate.rs:24:5
|
LL | extern crate std as foo;
| ^^^^^^^^^^^^^^^^^^^^^^^^ help: remove it
LL | extern crate std;
| ^^^^^^^^^^^^^^^^^ help: remove it