bjoernager/rust
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WIP: Find the imports that were used to reach a method

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And add tests for some corner cases we have to consider.
This commit is contained in:
Niko Matsakis 2021-06-17 06:10:38 -04:00
parent 56108f67b1
commit dbc9da7962
3 changed files with 118 additions and 6 deletions
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39
compiler/rustc_typeck/src/check/method/prelude2021.rs
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@ -1,3 +1,5 @@
use hir::def_id::DefId;
use hir::HirId;
use rustc_ast::Mutability;
use rustc_errors::Applicability;
use rustc_hir as hir;
@ -48,7 +50,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
call_expr.span,
|lint| {
let sp = call_expr.span;
let trait_name = self.tcx.def_path_str(pick.item.container.id());
let trait_name =
self.trait_path_or_bare_name(call_expr.hir_id, pick.item.container.id());
let mut lint = lint.build(&format!(
"trait method `{}` will become ambiguous in Rust 2021",
@ -144,16 +147,16 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
self.tcx.struct_span_lint_hir(FUTURE_PRELUDE_COLLISION, expr_id, span, |lint| {
// "type" refers to either a type or, more likely, a trait from which
// the associated function or method is from.
let type_name = self.tcx.def_path_str(pick.item.container.id());
let type_generics = self.tcx.generics_of(pick.item.container.id());
let trait_path = self.trait_path_or_bare_name(expr_id, pick.item.container.id());
let trait_generics = self.tcx.generics_of(pick.item.container.id());
let parameter_count = type_generics.count() - (type_generics.has_self as usize);
let parameter_count = trait_generics.count() - (trait_generics.has_self as usize);
let trait_name = if parameter_count == 0 {
type_name
trait_path
} else {
format!(
"{}<{}>",
type_name,
trait_path,
std::iter::repeat("_").take(parameter_count).collect::<Vec<_>>().join(", ")
)
};
@ -179,4 +182,28 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
lint.emit();
});
}
fn trait_path_or_bare_name(&self, expr_hir_id: HirId, trait_def_id: DefId) -> String {
self.trait_path(expr_hir_id, trait_def_id).unwrap_or_else(|| {
let key = self.tcx.def_key(trait_def_id);
format!("{}", key.disambiguated_data.data)
})
}
fn trait_path(&self, expr_hir_id: HirId, trait_def_id: DefId) -> Option<String> {
let applicable_traits = self.tcx.in_scope_traits(expr_hir_id)?;
let applicable_trait = applicable_traits.iter().find(|t| t.def_id == trait_def_id)?;
if applicable_trait.import_ids.is_empty() {
// The trait was declared within the module, we only need to use its name.
return None;
}
for &import_id in &applicable_trait.import_ids {
let hir_id = self.tcx.hir().local_def_id_to_hir_id(import_id);
let item = self.tcx.hir().expect_item(hir_id);
debug!(?item, ?import_id, "import_id");
}
return None;
}
}