rustc_ast_lowering: Stop lowering imports into multiple items

Lower them into a single item with multiple resolutions instead.
This also allows to remove additional `NodId`s and `DefId`s related to those additional items.

Author: petrochenkov

clippy_lints/src/single_component_path_imports.rs

@@ -149,7 +149,7 @@ impl SingleComponentPathImports {
 
                 // keep track of `use some_module;` usages
                 if segments.len() == 1 {
-                    if let UseTreeKind::Simple(None, _, _) = use_tree.kind {
+                    if let UseTreeKind::Simple(None) = use_tree.kind {
                         let name = segments[0].ident.name;
                         if !macros.contains(&name) {
                             single_use_usages.push(SingleUse {
@@ -169,7 +169,7 @@ impl SingleComponentPathImports {
                         for tree in trees {
                             let segments = &tree.0.prefix.segments;
                             if segments.len() == 1 {
-                                if let UseTreeKind::Simple(None, _, _) = tree.0.kind {
+                                if let UseTreeKind::Simple(None) = tree.0.kind {
                                     let name = segments[0].ident.name;
                                     if !macros.contains(&name) {
                                         single_use_usages.push(SingleUse {

clippy_lints/src/unnecessary_self_imports.rs

@@ -57,7 +57,7 @@ impl EarlyLintPass for UnnecessarySelfImports {
                             format!(
                                 "{}{};",
                                 last_segment.ident,
-                                if let UseTreeKind::Simple(Some(alias), ..) = self_tree.kind { format!(" as {alias}") } else { String::new() },
+                                if let UseTreeKind::Simple(Some(alias)) = self_tree.kind { format!(" as {alias}") } else { String::new() },
                             ),
                             Applicability::MaybeIncorrect,
                         );

clippy_lints/src/unsafe_removed_from_name.rs

@@ -39,7 +39,7 @@ impl EarlyLintPass for UnsafeNameRemoval {
 
 fn check_use_tree(use_tree: &UseTree, cx: &EarlyContext<'_>, span: Span) {
     match use_tree.kind {
-        UseTreeKind::Simple(Some(new_name), ..) => {
+        UseTreeKind::Simple(Some(new_name)) => {
             let old_name = use_tree
                 .prefix
                 .segments
@@ -48,7 +48,7 @@ fn check_use_tree(use_tree: &UseTree, cx: &EarlyContext<'_>, span: Span) {
                 .ident;
             unsafe_to_safe_check(old_name, new_name, cx, span);
         },
-        UseTreeKind::Simple(None, ..) | UseTreeKind::Glob => {},
+        UseTreeKind::Simple(None) | UseTreeKind::Glob => {},
         UseTreeKind::Nested(ref nested_use_tree) => {
             for (use_tree, _) in nested_use_tree {
                 check_use_tree(use_tree, cx, span);

clippy_utils/src/ast_utils.rs

@@ -566,7 +566,7 @@ pub fn eq_use_tree_kind(l: &UseTreeKind, r: &UseTreeKind) -> bool {
     use UseTreeKind::*;
     match (l, r) {
         (Glob, Glob) => true,
-        (Simple(l, _, _), Simple(r, _, _)) => both(l, r, |l, r| eq_id(*l, *r)),
+        (Simple(l), Simple(r)) => both(l, r, |l, r| eq_id(*l, *r)),
         (Nested(l), Nested(r)) => over(l, r, |(l, _), (r, _)| eq_use_tree(l, r)),
         _ => false,
     }

tests/ui/macro_use_imports.stderr

@@ -1,8 +1,8 @@
 error: `macro_use` attributes are no longer needed in the Rust 2018 edition
-  --> $DIR/macro_use_imports.rs:23:5
+  --> $DIR/macro_use_imports.rs:25:5
    |
 LL |     #[macro_use]
-   |     ^^^^^^^^^^^^ help: remove the attribute and import the macro directly, try: `use mac::{inner::foofoo, inner::try_err};`
+   |     ^^^^^^^^^^^^ help: remove the attribute and import the macro directly, try: `use mac::inner::nested::string_add;`
    |
    = note: `-D clippy::macro-use-imports` implied by `-D warnings`
 
@@ -13,10 +13,10 @@ LL |     #[macro_use]
    |     ^^^^^^^^^^^^ help: remove the attribute and import the macro directly, try: `use mini_mac::ClippyMiniMacroTest;`
 
 error: `macro_use` attributes are no longer needed in the Rust 2018 edition
-  --> $DIR/macro_use_imports.rs:25:5
+  --> $DIR/macro_use_imports.rs:23:5
    |
 LL |     #[macro_use]
-   |     ^^^^^^^^^^^^ help: remove the attribute and import the macro directly, try: `use mac::inner::nested::string_add;`
+   |     ^^^^^^^^^^^^ help: remove the attribute and import the macro directly, try: `use mac::{inner::foofoo, inner::try_err};`
 
 error: `macro_use` attributes are no longer needed in the Rust 2018 edition
   --> $DIR/macro_use_imports.rs:19:5