Auto merge of rust-lang#15627 - jmintb:sort_imports, r=Veykril

feat: Prioritize import suggestions based on the expected type

Hi, this is a draft PR to solve rust-lang#15384. `Adt` types work and now I have a few questions :)

1. What other types make sense in this context? Looking at [ModuleDef](https://github.com/rust-lang/rust-analyzer/blob/05666441bafd6010787a4097a6bd44266ad21018/crates/hir/src/lib.rs#L275) I am thinking everything except Modules.
2. Is there an existing way of converting between `ModeuleDef` and `hir::Type` in the rustanalyzer code base?
3. Does this approach seem sound to you?

Ups: Upon writing this I just realised that the enum test is invalided as there are no enum variants and this no variant is passed as a function argument.

Author: bors

crates/ide-completion/src/completions/dot.rs

@@ -940,9 +940,9 @@ impl Foo { fn foo(&self) { $0 } }"#,
             expect![[r#"
                 fd self.field i32
                 lc self       &Foo
-                sp Self
-                st Foo
-                bt u32
+                sp Self       Foo
+                st Foo        Foo
+                bt u32        u32
                 me self.foo() fn(&self)
             "#]],
         );
@@ -954,9 +954,9 @@ impl Foo { fn foo(&mut self) { $0 } }"#,
             expect![[r#"
                 fd self.0     i32
                 lc self       &mut Foo
-                sp Self
-                st Foo
-                bt u32
+                sp Self       Foo
+                st Foo        Foo
+                bt u32        u32
                 me self.foo() fn(&mut self)
             "#]],
         );

crates/ide-completion/src/completions/item_list/trait_impl.rs

@@ -417,10 +417,10 @@ impl Test for T {
 }
 ",
             expect![[r#"
-                sp Self
-                st T
+                sp Self T
+                st T    T
                 tt Test
-                bt u32
+                bt u32  u32
             "#]],
         );
 
@@ -526,10 +526,10 @@ impl Test for T {
 }
 ",
             expect![[r#"
-                sp Self
-                st T
+                sp Self T
+                st T    T
                 tt Test
-                bt u32
+                bt u32  u32
             "#]],
         );
 
@@ -543,10 +543,10 @@ impl Test for T {
 }
 ",
             expect![[r#"
-                sp Self
-                st T
+                sp Self T
+                st T    T
                 tt Test
-                bt u32
+                bt u32  u32
             "#]],
         );
 
@@ -562,10 +562,10 @@ impl Test for T {
 }
 ",
             expect![[r#"
-                sp Self
-                st T
+                sp Self T
+                st T    T
                 tt Test
-                bt u32
+                bt u32  u32
             "#]],
         );
 
@@ -610,10 +610,10 @@ impl Test for T {
 }
 ",
             expect![[r#"
-                sp Self
-                st T
+                sp Self T
+                st T    T
                 tt Test
-                bt u32
+                bt u32  u32
             "#]],
         );
 

crates/ide-completion/src/completions/use_.rs

@@ -71,9 +71,9 @@ pub(crate) fn complete_use_path(
 
                         if add_resolution {
                             let mut builder = Builder::from_resolution(ctx, path_ctx, name, def);
-                            builder.set_relevance(CompletionRelevance {
+                            builder.with_relevance(|r| CompletionRelevance {
                                 is_name_already_imported,
-                                ..Default::default()
+                                ..r
                             });
                             acc.add(builder.build(ctx.db));
                         }

crates/ide-completion/src/item.rs

@@ -1,6 +1,6 @@
 //! See `CompletionItem` structure.
 
-use std::fmt;
+use std::{fmt, mem};
 
 use hir::Mutability;
 use ide_db::{
@@ -570,6 +570,13 @@ impl Builder {
         self.relevance = relevance;
         self
     }
+    pub(crate) fn with_relevance(
+        &mut self,
+        relevance: impl FnOnce(CompletionRelevance) -> CompletionRelevance,
+    ) -> &mut Builder {
+        self.relevance = relevance(mem::take(&mut self.relevance));
+        self
+    }
     pub(crate) fn trigger_call_info(&mut self) -> &mut Builder {
         self.trigger_call_info = true;
         self