**Merge Imports** assist handles self

crates/ra_assists/src/handlers/merge_imports.rs

@@ -164,6 +164,33 @@ use std::fmt::{Display, Debug};
         );
     }
 
+    #[test]
+    fn merge_self1() {
+        check_assist(
+            merge_imports,
+            r"
+use std::fmt<|>;
+use std::fmt::Display;
+",
+            r"
+use std::fmt::{self, Display};
+",
+        );
+    }
+
+    #[test]
+    fn merge_self2() {
+        check_assist(
+            merge_imports,
+            r"
+use std::{fmt, <|>fmt::Display};
+",
+            r"
+use std::{fmt::{Display, self}};
+",
+        );
+    }
+
     #[test]
     fn test_merge_nested() {
         check_assist(

crates/syntax/src/ast/edit.rs

@@ -313,10 +313,15 @@ impl ast::UseTree {
 
     #[must_use]
     pub fn split_prefix(&self, prefix: &ast::Path) -> ast::UseTree {
-        let suffix = match split_path_prefix(&prefix) {
+        let suffix = if self.path().as_ref() == Some(prefix) && self.use_tree_list().is_none() {
+            make::path_unqualified(make::path_segment_self())
+        } else {
+            match split_path_prefix(&prefix) {
                 Some(it) => it,
                 None => return self.clone(),
+            }
         };
+
         let use_tree = make::use_tree(
             suffix,
             self.use_tree_list(),

crates/syntax/src/ast/make.rs

@@ -24,6 +24,9 @@ pub fn ty(text: &str) -> ast::Type {
 pub fn path_segment(name_ref: ast::NameRef) -> ast::PathSegment {
     ast_from_text(&format!("use {};", name_ref))
 }
+pub fn path_segment_self() -> ast::PathSegment {
+    ast_from_text("use self;")
+}
 pub fn path_unqualified(segment: ast::PathSegment) -> ast::Path {
     path_from_text(&format!("use {}", segment))
 }