Resolve through local re-exports in lookup_path (#14772)

Fixes #14767

A long standing issue revealed by
#14397

changelog: none

Author: dswij

clippy_utils/src/paths.rs

@@ -8,9 +8,9 @@ use crate::{MaybePath, path_def_id, sym};
 use rustc_ast::Mutability;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_hir::def::Namespace::{MacroNS, TypeNS, ValueNS};
-use rustc_hir::def::{DefKind, Namespace};
+use rustc_hir::def::{DefKind, Namespace, Res};
 use rustc_hir::def_id::{DefId, LOCAL_CRATE, LocalDefId};
-use rustc_hir::{ImplItemRef, ItemKind, Node, OwnerId, TraitItemRef};
+use rustc_hir::{ImplItemRef, ItemKind, Node, OwnerId, TraitItemRef, UseKind};
 use rustc_lint::LateContext;
 use rustc_middle::ty::fast_reject::SimplifiedType;
 use rustc_middle::ty::{FloatTy, IntTy, Ty, TyCtxt, UintTy};
@@ -302,8 +302,19 @@ fn local_item_child_by_name(tcx: TyCtxt<'_>, local_id: LocalDefId, ns: PathNS, n
 
     match item_kind {
         ItemKind::Mod(_, r#mod) => r#mod.item_ids.iter().find_map(|&item_id| {
-            let ident = tcx.hir_item(item_id).kind.ident()?;
-            res(ident, item_id.owner_id)
+            let item = tcx.hir_item(item_id);
+            if let ItemKind::Use(path, UseKind::Single(ident)) = item.kind {
+                if ident.name == name {
+                    path.res
+                        .iter()
+                        .find(|res| ns.matches(res.ns()))
+                        .and_then(Res::opt_def_id)
+                } else {
+                    None
+                }
+            } else {
+                res(item.kind.ident()?, item_id.owner_id)
+            }
         }),
         ItemKind::Impl(r#impl) => r#impl
             .items

tests/ui-toml/toml_disallowed_methods/clippy.toml

@@ -14,4 +14,7 @@ disallowed-methods = [
     "conf_disallowed_methods::Struct::method",
     "conf_disallowed_methods::Trait::provided_method",
     "conf_disallowed_methods::Trait::implemented_method",
+    # re-exports
+    "conf_disallowed_methods::identity",
+    "conf_disallowed_methods::renamed",
 ]

tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs

@@ -8,6 +8,9 @@ extern crate regex;
 use futures::stream::{empty, select_all};
 use regex::Regex;
 
+use std::convert::identity;
+use std::hint::black_box as renamed;
+
 fn local_fn() {}
 
 struct Struct;
@@ -71,4 +74,9 @@ fn main() {
     //~^ disallowed_methods
     s.implemented_method();
     //~^ disallowed_methods
+
+    identity(());
+    //~^ disallowed_methods
+    renamed(1);
+    //~^ disallowed_methods
 }

tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.stderr

@@ -1,5 +1,5 @@
 error: use of a disallowed method `regex::Regex::new`
-  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:33:14
+  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:36:14
    |
 LL |     let re = Regex::new(r"ab.*c").unwrap();
    |              ^^^^^^^^^^
@@ -8,84 +8,96 @@ LL |     let re = Regex::new(r"ab.*c").unwrap();
    = help: to override `-D warnings` add `#[allow(clippy::disallowed_methods)]`
 
 error: use of a disallowed method `regex::Regex::is_match`
-  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:35:8
+  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:38:8
    |
 LL |     re.is_match("abc");
    |        ^^^^^^^^
    |
    = note: no matching allowed
 
 error: use of a disallowed method `std::iter::Iterator::sum`
-  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:39:14
+  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:42:14
    |
 LL |     a.iter().sum::<i32>();
    |              ^^^
 
 error: use of a disallowed method `slice::sort_unstable`
-  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:42:7
+  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:45:7
    |
 LL |     a.sort_unstable();
    |       ^^^^^^^^^^^^^
 
 error: use of a disallowed method `f32::clamp`
-  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:46:20
+  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:49:20
    |
 LL |     let _ = 2.0f32.clamp(3.0f32, 4.0f32);
    |                    ^^^^^
 
 error: use of a disallowed method `regex::Regex::new`
-  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:50:61
+  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:53:61
    |
 LL |     let indirect: fn(&str) -> Result<Regex, regex::Error> = Regex::new;
    |                                                             ^^^^^^^^^^
 
 error: use of a disallowed method `f32::clamp`
-  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:54:28
+  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:57:28
    |
 LL |     let in_call = Box::new(f32::clamp);
    |                            ^^^^^^^^^^
 
 error: use of a disallowed method `regex::Regex::new`
-  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:56:53
+  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:59:53
    |
 LL |     let in_method_call = ["^", "$"].into_iter().map(Regex::new);
    |                                                     ^^^^^^^^^^
 
 error: use of a disallowed method `futures::stream::select_all`
-  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:60:31
+  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:63:31
    |
 LL |     let same_name_as_module = select_all(vec![empty::<()>()]);
    |                               ^^^^^^^^^^
 
 error: use of a disallowed method `conf_disallowed_methods::local_fn`
-  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:63:5
+  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:66:5
    |
 LL |     local_fn();
    |     ^^^^^^^^
 
 error: use of a disallowed method `conf_disallowed_methods::local_mod::f`
-  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:65:5
+  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:68:5
    |
 LL |     local_mod::f();
    |     ^^^^^^^^^^^^
 
 error: use of a disallowed method `conf_disallowed_methods::Struct::method`
-  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:68:7
+  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:71:7
    |
 LL |     s.method();
    |       ^^^^^^
 
 error: use of a disallowed method `conf_disallowed_methods::Trait::provided_method`
-  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:70:7
+  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:73:7
    |
 LL |     s.provided_method();
    |       ^^^^^^^^^^^^^^^
 
 error: use of a disallowed method `conf_disallowed_methods::Trait::implemented_method`
-  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:72:7
+  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:75:7
    |
 LL |     s.implemented_method();
    |       ^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 14 previous errors
+error: use of a disallowed method `conf_disallowed_methods::identity`
+  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:78:5
+   |
+LL |     identity(());
+   |     ^^^^^^^^
+
+error: use of a disallowed method `conf_disallowed_methods::renamed`
+  --> tests/ui-toml/toml_disallowed_methods/conf_disallowed_methods.rs:80:5
+   |
+LL |     renamed(1);
+   |     ^^^^^^^
+
+error: aborting due to 16 previous errors