2 files changed, 159 insertions, 20 deletions

diff --git a/crates/assists/src/handlers/remove_unused_param.rs b/crates/assists/src/handlers/remove_unused_param.rs
index 5fccca54b..1ff5e92b0 100644
--- a/crates/assists/src/handlers/remove_unused_param.rs
+++ b/crates/assists/src/handlers/remove_unused_param.rs
@@ -73,7 +73,8 @@ fn process_usage(
     let source_file = ctx.sema.parse(usage.file_range.file_id);
     let call_expr: ast::CallExpr =
         find_node_at_range(source_file.syntax(), usage.file_range.range)?;
-    if call_expr.expr()?.syntax().text_range() != usage.file_range.range {
+    let call_expr_range = call_expr.expr()?.syntax().text_range();
+    if !call_expr_range.contains_range(usage.file_range.range) {
         return None;
     }
     let arg = call_expr.arg_list()?.args().nth(arg_to_remove)?;
@@ -118,6 +119,53 @@ fn b() { foo(9, ) }
     }
 
     #[test]
+    fn remove_unused_qualified_call() {
+        check_assist(
+            remove_unused_param,
+            r#"
+mod bar { pub fn foo(x: i32, <|>y: i32) { x; } }
+fn b() { bar::foo(9, 2) }
+"#,
+            r#"
+mod bar { pub fn foo(x: i32) { x; } }
+fn b() { bar::foo(9) }
+"#,
+        );
+    }
+
+    #[test]
+    fn remove_unused_turbofished_func() {
+        check_assist(
+            remove_unused_param,
+            r#"
+pub fn foo<T>(x: T, <|>y: i32) { x; }
+fn b() { foo::<i32>(9, 2) }
+"#,
+            r#"
+pub fn foo<T>(x: T) { x; }
+fn b() { foo::<i32>(9) }
+"#,
+        );
+    }
+
+    #[test]
+    fn remove_unused_generic_unused_param_func() {
+        check_assist(
+            remove_unused_param,
+            r#"
+pub fn foo<T>(x: i32, <|>y: T) { x; }
+fn b() { foo::<i32>(9, 2) }
+fn b2() { foo(9, 2) }
+"#,
+            r#"
+pub fn foo<T>(x: i32) { x; }
+fn b() { foo::<i32>(9) }
+fn b2() { foo(9) }
+"#,
+        );
+    }
+
+    #[test]
     fn keep_used() {
         mark::check!(keep_used);
         check_assist_not_applicable(
@@ -128,4 +176,37 @@ fn main() { foo(9, 2) }
 "#,
         );
     }
+
+    #[test]
+    fn remove_across_files() {
+        check_assist(
+            remove_unused_param,
+            r#"
+//- /main.rs
+fn foo(x: i32, <|>y: i32) { x; }
+
+mod foo;
+
+//- /foo.rs
+use super::foo;
+
+fn bar() {
+    let _ = foo(1, 2);
+}
+"#,
+            r#"
+//- /main.rs
+fn foo(x: i32) { x; }
+
+mod foo;
+
+//- /foo.rs
+use super::foo;
+
+fn bar() {
+    let _ = foo(1);
+}
+"#,
+        )
+    }
 }
diff --git a/crates/assists/src/utils/insert_use.rs b/crates/assists/src/utils/insert_use.rs
index 84a0dffdd..af3fc96b6 100644
--- a/crates/assists/src/utils/insert_use.rs
+++ b/crates/assists/src/utils/insert_use.rs
@@ -9,7 +9,7 @@ use syntax::{
         edit::{AstNodeEdit, IndentLevel},
         make, AstNode, PathSegmentKind, VisibilityOwner,
     },
-    InsertPosition, SyntaxElement, SyntaxNode,
+    AstToken, InsertPosition, NodeOrToken, SyntaxElement, SyntaxNode, SyntaxToken,
 };
 use test_utils::mark;
 
@@ -63,27 +63,30 @@ impl ImportScope {
         }
     }
 
-    fn insert_pos_after_inner_attribute(&self) -> (InsertPosition<SyntaxElement>, AddBlankLine) {
-        // check if the scope has inner attributes, we dont want to insert in front of them
-        match self
-            .as_syntax_node()
-            .children()
-            // no flat_map here cause we want to short circuit the iterator
-            .map(ast::Attr::cast)
-            .take_while(|attr| {
-                attr.as_ref().map(|attr| attr.kind() == ast::AttrKind::Inner).unwrap_or(false)
+    fn insert_pos_after_last_inner_element(&self) -> (InsertPosition<SyntaxElement>, AddBlankLine) {
+        self.as_syntax_node()
+            .children_with_tokens()
+            .filter(|child| match child {
+                NodeOrToken::Node(node) => is_inner_attribute(node.clone()),
+                NodeOrToken::Token(token) => is_inner_comment(token.clone()),
             })
             .last()
-            .flatten()
-        {
-            Some(attr) => {
-                (InsertPosition::After(attr.syntax().clone().into()), AddBlankLine::BeforeTwice)
-            }
-            None => self.first_insert_pos(),
-        }
+            .map(|last_inner_element| {
+                (InsertPosition::After(last_inner_element.into()), AddBlankLine::BeforeTwice)
+            })
+            .unwrap_or_else(|| self.first_insert_pos())
     }
 }
 
+fn is_inner_attribute(node: SyntaxNode) -> bool {
+    ast::Attr::cast(node).map(|attr| attr.kind()) == Some(ast::AttrKind::Inner)
+}
+
+fn is_inner_comment(token: SyntaxToken) -> bool {
+    ast::Comment::cast(token).and_then(|comment| comment.kind().doc)
+        == Some(ast::CommentPlacement::Inner)
+}
+
 /// Insert an import path into the given file/node. A `merge` value of none indicates that no import merging is allowed to occur.
 pub(crate) fn insert_use<'a>(
     scope: &ImportScope,
@@ -558,7 +561,7 @@ fn find_insert_position(
                             (InsertPosition::After(node.into()), AddBlankLine::BeforeTwice)
                         }
                         // there are no imports in this file at all
-                        None => scope.insert_pos_after_inner_attribute(),
+                        None => scope.insert_pos_after_last_inner_element(),
                     },
                 }
             }
@@ -830,12 +833,67 @@ use foo::bar;",
             "foo::bar",
             r"#![allow(unused_imports)]
 
+#![no_std]
 fn main() {}",
             r"#![allow(unused_imports)]
 
-use foo::bar;
+#![no_std]
 
+use foo::bar;
 fn main() {}",
+        );
+    }
+
+    #[test]
+    fn inserts_after_single_line_inner_comments() {
+        check_none(
+            "foo::bar::Baz",
+            "//! Single line inner comments do not allow any code before them.",
+            r#"//! Single line inner comments do not allow any code before them.
+
+use foo::bar::Baz;"#,
+        );
+    }
+
+    #[test]
+    fn inserts_after_multiline_inner_comments() {
+        check_none(
+            "foo::bar::Baz",
+            r#"/*! Multiline inner comments do not allow any code before them. */
+
+/*! Still an inner comment, cannot place any code before. */
+fn main() {}"#,
+            r#"/*! Multiline inner comments do not allow any code before them. */
+
+/*! Still an inner comment, cannot place any code before. */
+
+use foo::bar::Baz;
+fn main() {}"#,
+        )
+    }
+
+    #[test]
+    fn inserts_after_all_inner_items() {
+        check_none(
+            "foo::bar::Baz",
+            r#"#![allow(unused_imports)]
+/*! Multiline line comment 2 */
+
+
+//! Single line comment 1
+#![no_std]
+//! Single line comment 2
+fn main() {}"#,
+            r#"#![allow(unused_imports)]
+/*! Multiline line comment 2 */
+
+
+//! Single line comment 1
+#![no_std]
+//! Single line comment 2
+
+use foo::bar::Baz;
+fn main() {}"#,
         )
     }