7 files changed, 414 insertions, 44 deletions

diff --git a/crates/ide_assists/src/assist_context.rs b/crates/ide_assists/src/assist_context.rs
index 8714e4978..112939948 100644
--- a/crates/ide_assists/src/assist_context.rs
+++ b/crates/ide_assists/src/assist_context.rs
@@ -19,7 +19,9 @@ use syntax::{
 };
 use text_edit::{TextEdit, TextEditBuilder};
 
-use crate::{assist_config::AssistConfig, Assist, AssistId, AssistKind, GroupLabel};
+use crate::{
+    assist_config::AssistConfig, Assist, AssistId, AssistKind, AssistResolveStrategy, GroupLabel,
+};
 
 /// `AssistContext` allows to apply an assist or check if it could be applied.
 ///
@@ -105,14 +107,14 @@ impl<'a> AssistContext<'a> {
 }
 
 pub(crate) struct Assists {
-    resolve: bool,
     file: FileId,
+    resolve: AssistResolveStrategy,
     buf: Vec<Assist>,
     allowed: Option<Vec<AssistKind>>,
 }
 
 impl Assists {
-    pub(crate) fn new(ctx: &AssistContext, resolve: bool) -> Assists {
+    pub(crate) fn new(ctx: &AssistContext, resolve: AssistResolveStrategy) -> Assists {
         Assists {
             resolve,
             file: ctx.frange.file_id,
@@ -158,7 +160,7 @@ impl Assists {
     }
 
     fn add_impl(&mut self, mut assist: Assist, f: impl FnOnce(&mut AssistBuilder)) -> Option<()> {
-        let source_change = if self.resolve {
+        let source_change = if self.resolve.should_resolve(&assist.id) {
             let mut builder = AssistBuilder::new(self.file);
             f(&mut builder);
             Some(builder.finish())
@@ -185,7 +187,29 @@ pub(crate) struct AssistBuilder {
     source_change: SourceChange,
 
     /// Maps the original, immutable `SyntaxNode` to a `clone_for_update` twin.
-    mutated_tree: Option<(SyntaxNode, SyntaxNode)>,
+    mutated_tree: Option<TreeMutator>,
+}
+
+pub(crate) struct TreeMutator {
+    immutable: SyntaxNode,
+    mutable_clone: SyntaxNode,
+}
+
+impl TreeMutator {
+    pub(crate) fn new(immutable: &SyntaxNode) -> TreeMutator {
+        let immutable = immutable.ancestors().last().unwrap();
+        let mutable_clone = immutable.clone_for_update();
+        TreeMutator { immutable, mutable_clone }
+    }
+
+    pub(crate) fn make_mut<N: AstNode>(&self, node: &N) -> N {
+        N::cast(self.make_syntax_mut(node.syntax())).unwrap()
+    }
+
+    pub(crate) fn make_syntax_mut(&self, node: &SyntaxNode) -> SyntaxNode {
+        let ptr = SyntaxNodePtr::new(node);
+        ptr.to_node(&self.mutable_clone)
+    }
 }
 
 impl AssistBuilder {
@@ -204,8 +228,8 @@ impl AssistBuilder {
     }
 
     fn commit(&mut self) {
-        if let Some((old, new)) = self.mutated_tree.take() {
-            algo::diff(&old, &new).into_text_edit(&mut self.edit)
+        if let Some(tm) = self.mutated_tree.take() {
+            algo::diff(&tm.immutable, &tm.mutable_clone).into_text_edit(&mut self.edit)
         }
 
         let edit = mem::take(&mut self.edit).finish();
@@ -228,16 +252,7 @@ impl AssistBuilder {
     /// phase, and then get their mutable couterparts using `make_mut` in the
     /// mutable state.
     pub(crate) fn make_mut(&mut self, node: SyntaxNode) -> SyntaxNode {
-        let root = &self
-            .mutated_tree
-            .get_or_insert_with(|| {
-                let immutable = node.ancestors().last().unwrap();
-                let mutable = immutable.clone_for_update();
-                (immutable, mutable)
-            })
-            .1;
-        let ptr = SyntaxNodePtr::new(&&node);
-        ptr.to_node(root)
+        self.mutated_tree.get_or_insert_with(|| TreeMutator::new(&node)).make_syntax_mut(&node)
     }
 
     /// Remove specified `range` of text.
diff --git a/crates/ide_assists/src/handlers/extract_function.rs b/crates/ide_assists/src/handlers/extract_function.rs
index 5f80a40c8..93b28370c 100644
--- a/crates/ide_assists/src/handlers/extract_function.rs
+++ b/crates/ide_assists/src/handlers/extract_function.rs
@@ -16,12 +16,13 @@ use syntax::{
         edit::{AstNodeEdit, IndentLevel},
         AstNode,
     },
+    ted,
     SyntaxKind::{self, BLOCK_EXPR, BREAK_EXPR, COMMENT, PATH_EXPR, RETURN_EXPR},
     SyntaxNode, SyntaxToken, TextRange, TextSize, TokenAtOffset, WalkEvent, T,
 };
 
 use crate::{
-    assist_context::{AssistContext, Assists},
+    assist_context::{AssistContext, Assists, TreeMutator},
     AssistId,
 };
 
@@ -1183,7 +1184,7 @@ fn make_ret_ty(ctx: &AssistContext, module: hir::Module, fun: &Function) -> Opti
         }
         FlowHandler::Try { kind: TryKind::Result { ty: parent_ret_ty } } => {
             let handler_ty = parent_ret_ty
-                .type_parameters()
+                .type_arguments()
                 .nth(1)
                 .map(|ty| make_ty(&ty, ctx, module))
                 .unwrap_or_else(make::ty_unit);
@@ -1366,7 +1367,10 @@ fn rewrite_body_segment(
 
 /// change all usages to account for added `&`/`&mut` for some params
 fn fix_param_usages(ctx: &AssistContext, params: &[Param], syntax: &SyntaxNode) -> SyntaxNode {
-    let mut rewriter = SyntaxRewriter::default();
+    let mut usages_for_param: Vec<(&Param, Vec<ast::Expr>)> = Vec::new();
+
+    let tm = TreeMutator::new(syntax);
+
     for param in params {
         if !param.kind().is_ref() {
             continue;
@@ -1376,30 +1380,39 @@ fn fix_param_usages(ctx: &AssistContext, params: &[Param], syntax: &SyntaxNode)
         let usages = usages
             .iter()
             .filter(|reference| syntax.text_range().contains_range(reference.range))
-            .filter_map(|reference| path_element_of_reference(syntax, reference));
-        for path in usages {
-            match path.syntax().ancestors().skip(1).find_map(ast::Expr::cast) {
+            .filter_map(|reference| path_element_of_reference(syntax, reference))
+            .map(|expr| tm.make_mut(&expr));
+
+        usages_for_param.push((param, usages.collect()));
+    }
+
+    let res = tm.make_syntax_mut(syntax);
+
+    for (param, usages) in usages_for_param {
+        for usage in usages {
+            match usage.syntax().ancestors().skip(1).find_map(ast::Expr::cast) {
                 Some(ast::Expr::MethodCallExpr(_)) | Some(ast::Expr::FieldExpr(_)) => {
                     // do nothing
                 }
                 Some(ast::Expr::RefExpr(node))
                     if param.kind() == ParamKind::MutRef && node.mut_token().is_some() =>
                 {
-                    rewriter.replace_ast(&node.clone().into(), &node.expr().unwrap());
+                    ted::replace(node.syntax(), node.expr().unwrap().syntax());
                 }
                 Some(ast::Expr::RefExpr(node))
                     if param.kind() == ParamKind::SharedRef && node.mut_token().is_none() =>
                 {
-                    rewriter.replace_ast(&node.clone().into(), &node.expr().unwrap());
+                    ted::replace(node.syntax(), node.expr().unwrap().syntax());
                 }
                 Some(_) | None => {
-                    rewriter.replace_ast(&path, &make::expr_prefix(T![*], path.clone()));
+                    let p = &make::expr_prefix(T![*], usage.clone()).clone_for_update();
+                    ted::replace(usage.syntax(), p.syntax())
                 }
-            };
+            }
         }
     }
 
-    rewriter.rewrite(syntax)
+    res
 }
 
 fn update_external_control_flow(handler: &FlowHandler, syntax: &SyntaxNode) -> SyntaxNode {
diff --git a/crates/ide_assists/src/handlers/generate_from_impl_for_enum.rs b/crates/ide_assists/src/handlers/generate_from_impl_for_enum.rs
index c13c6eebe..ce6998d82 100644
--- a/crates/ide_assists/src/handlers/generate_from_impl_for_enum.rs
+++ b/crates/ide_assists/src/handlers/generate_from_impl_for_enum.rs
@@ -91,7 +91,7 @@ fn existing_from_impl(
 
     let enum_type = enum_.ty(sema.db);
 
-    let wrapped_type = variant.fields(sema.db).get(0)?.signature_ty(sema.db);
+    let wrapped_type = variant.fields(sema.db).get(0)?.ty(sema.db);
 
     if enum_type.impls_trait(sema.db, from_trait, &[wrapped_type]) {
         Some(())
diff --git a/crates/ide_assists/src/handlers/reorder_impl.rs b/crates/ide_assists/src/handlers/reorder_impl.rs
index 72d889248..54a9a468e 100644
--- a/crates/ide_assists/src/handlers/reorder_impl.rs
+++ b/crates/ide_assists/src/handlers/reorder_impl.rs
@@ -79,9 +79,12 @@ pub(crate) fn reorder_impl(acc: &mut Assists, ctx: &AssistContext) -> Option<()>
         "Sort methods",
         target,
         |builder| {
-            methods.into_iter().zip(sorted).for_each(|(old, new)| {
-                ted::replace(builder.make_ast_mut(old).syntax(), new.clone_for_update().syntax())
-            });
+            let methods =
+                methods.into_iter().map(|fn_| builder.make_ast_mut(fn_)).collect::<Vec<_>>();
+            methods
+                .into_iter()
+                .zip(sorted)
+                .for_each(|(old, new)| ted::replace(old.syntax(), new.clone_for_update().syntax()));
         },
     )
 }
@@ -160,7 +163,7 @@ $0impl Bar for Foo {}
     }
 
     #[test]
-    fn reorder_impl_trait_methods() {
+    fn reorder_impl_trait_functions() {
         check_assist(
             reorder_impl,
             r#"
@@ -197,4 +200,33 @@ impl Bar for Foo {
         "#,
         )
     }
+
+    #[test]
+    fn reorder_impl_trait_methods_uneven_ident_lengths() {
+        check_assist(
+            reorder_impl,
+            r#"
+trait Bar {
+    fn foo(&mut self) {}
+    fn fooo(&mut self) {}
+}
+
+struct Foo;
+impl Bar for Foo {
+    fn fooo(&mut self) {}
+    fn foo(&mut self) {$0}
+}"#,
+            r#"
+trait Bar {
+    fn foo(&mut self) {}
+    fn fooo(&mut self) {}
+}
+
+struct Foo;
+impl Bar for Foo {
+    fn foo(&mut self) {}
+    fn fooo(&mut self) {}
+}"#,
+        )
+    }
 }
diff --git a/crates/ide_assists/src/lib.rs b/crates/ide_assists/src/lib.rs
index 88ae5c9a9..2e0c58504 100644
--- a/crates/ide_assists/src/lib.rs
+++ b/crates/ide_assists/src/lib.rs
@@ -17,6 +17,8 @@ mod tests;
 pub mod utils;
 pub mod ast_transform;
 
+use std::str::FromStr;
+
 use hir::Semantics;
 use ide_db::base_db::FileRange;
 use ide_db::{label::Label, source_change::SourceChange, RootDatabase};
@@ -56,6 +58,35 @@ impl AssistKind {
             _ => return false,
         }
     }
+
+    pub fn name(&self) -> &str {
+        match self {
+            AssistKind::None => "None",
+            AssistKind::QuickFix => "QuickFix",
+            AssistKind::Generate => "Generate",
+            AssistKind::Refactor => "Refactor",
+            AssistKind::RefactorExtract => "RefactorExtract",
+            AssistKind::RefactorInline => "RefactorInline",
+            AssistKind::RefactorRewrite => "RefactorRewrite",
+        }
+    }
+}
+
+impl FromStr for AssistKind {
+    type Err = String;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        match s {
+            "None" => Ok(AssistKind::None),
+            "QuickFix" => Ok(AssistKind::QuickFix),
+            "Generate" => Ok(AssistKind::Generate),
+            "Refactor" => Ok(AssistKind::Refactor),
+            "RefactorExtract" => Ok(AssistKind::RefactorExtract),
+            "RefactorInline" => Ok(AssistKind::RefactorInline),
+            "RefactorRewrite" => Ok(AssistKind::RefactorRewrite),
+            unknown => Err(format!("Unknown AssistKind: '{}'", unknown)),
+        }
+    }
 }
 
 /// Unique identifier of the assist, should not be shown to the user
@@ -63,6 +94,41 @@ impl AssistKind {
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct AssistId(pub &'static str, pub AssistKind);
 
+/// A way to control how many asssist to resolve during the assist resolution.
+/// When an assist is resolved, its edits are calculated that might be costly to always do by default.
+#[derive(Debug)]
+pub enum AssistResolveStrategy {
+    /// No assists should be resolved.
+    None,
+    /// All assists should be resolved.
+    All,
+    /// Only a certain assist should be resolved.
+    Single(SingleResolve),
+}
+
+/// Hold the [`AssistId`] data of a certain assist to resolve.
+/// The original id object cannot be used due to a `'static` lifetime
+/// and the requirement to construct this struct dynamically during the resolve handling.
+#[derive(Debug)]
+pub struct SingleResolve {
+    /// The id of the assist.
+    pub assist_id: String,
+    // The kind of the assist.
+    pub assist_kind: AssistKind,
+}
+
+impl AssistResolveStrategy {
+    pub fn should_resolve(&self, id: &AssistId) -> bool {
+        match self {
+            AssistResolveStrategy::None => false,
+            AssistResolveStrategy::All => true,
+            AssistResolveStrategy::Single(single_resolve) => {
+                single_resolve.assist_id == id.0 && single_resolve.assist_kind == id.1
+            }
+        }
+    }
+}
+
 #[derive(Clone, Debug)]
 pub struct GroupLabel(pub String);
 
@@ -91,7 +157,7 @@ impl Assist {
     pub fn get(
         db: &RootDatabase,
         config: &AssistConfig,
-        resolve: bool,
+        resolve: AssistResolveStrategy,
         range: FileRange,
     ) -> Vec<Assist> {
         let sema = Semantics::new(db);
diff --git a/crates/ide_assists/src/tests.rs b/crates/ide_assists/src/tests.rs
index 6f4f97361..9c2847998 100644
--- a/crates/ide_assists/src/tests.rs
+++ b/crates/ide_assists/src/tests.rs
@@ -12,7 +12,10 @@ use stdx::{format_to, trim_indent};
 use syntax::TextRange;
 use test_utils::{assert_eq_text, extract_offset};
 
-use crate::{handlers::Handler, Assist, AssistConfig, AssistContext, AssistKind, Assists};
+use crate::{
+    handlers::Handler, Assist, AssistConfig, AssistContext, AssistKind, AssistResolveStrategy,
+    Assists, SingleResolve,
+};
 
 pub(crate) const TEST_CONFIG: AssistConfig = AssistConfig {
     snippet_cap: SnippetCap::new(true),
@@ -65,14 +68,14 @@ fn check_doc_test(assist_id: &str, before: &str, after: &str) {
     let before = db.file_text(file_id).to_string();
     let frange = FileRange { file_id, range: selection.into() };
 
-    let assist = Assist::get(&db, &TEST_CONFIG, true, frange)
+    let assist = Assist::get(&db, &TEST_CONFIG, AssistResolveStrategy::All, frange)
         .into_iter()
         .find(|assist| assist.id.0 == assist_id)
         .unwrap_or_else(|| {
             panic!(
                 "\n\nAssist is not applicable: {}\nAvailable assists: {}",
                 assist_id,
-                Assist::get(&db, &TEST_CONFIG, false, frange)
+                Assist::get(&db, &TEST_CONFIG, AssistResolveStrategy::None, frange)
                     .into_iter()
                     .map(|assist| assist.id.0)
                     .collect::<Vec<_>>()
@@ -108,7 +111,7 @@ fn check(handler: Handler, before: &str, expected: ExpectedResult, assist_label:
     let sema = Semantics::new(&db);
     let config = TEST_CONFIG;
     let ctx = AssistContext::new(sema, &config, frange);
-    let mut acc = Assists::new(&ctx, true);
+    let mut acc = Assists::new(&ctx, AssistResolveStrategy::All);
     handler(&mut acc, &ctx);
     let mut res = acc.finish();
 
@@ -186,7 +189,7 @@ fn assist_order_field_struct() {
     let (before_cursor_pos, before) = extract_offset(before);
     let (db, file_id) = with_single_file(&before);
     let frange = FileRange { file_id, range: TextRange::empty(before_cursor_pos) };
-    let assists = Assist::get(&db, &TEST_CONFIG, false, frange);
+    let assists = Assist::get(&db, &TEST_CONFIG, AssistResolveStrategy::None, frange);
     let mut assists = assists.iter();
 
     assert_eq!(assists.next().expect("expected assist").label, "Change visibility to pub(crate)");
@@ -211,7 +214,7 @@ pub fn test_some_range(a: int) -> bool {
 "#,
     );
 
-    let assists = Assist::get(&db, &TEST_CONFIG, false, frange);
+    let assists = Assist::get(&db, &TEST_CONFIG, AssistResolveStrategy::None, frange);
     let expected = labels(&assists);
 
     expect![[r#"
@@ -240,7 +243,7 @@ pub fn test_some_range(a: int) -> bool {
         let mut cfg = TEST_CONFIG;
         cfg.allowed = Some(vec![AssistKind::Refactor]);
 
-        let assists = Assist::get(&db, &cfg, false, frange);
+        let assists = Assist::get(&db, &cfg, AssistResolveStrategy::None, frange);
         let expected = labels(&assists);
 
         expect![[r#"
@@ -255,7 +258,7 @@ pub fn test_some_range(a: int) -> bool {
     {
         let mut cfg = TEST_CONFIG;
         cfg.allowed = Some(vec![AssistKind::RefactorExtract]);
-        let assists = Assist::get(&db, &cfg, false, frange);
+        let assists = Assist::get(&db, &cfg, AssistResolveStrategy::None, frange);
         let expected = labels(&assists);
 
         expect![[r#"
@@ -268,9 +271,250 @@ pub fn test_some_range(a: int) -> bool {
     {
         let mut cfg = TEST_CONFIG;
         cfg.allowed = Some(vec![AssistKind::QuickFix]);
-        let assists = Assist::get(&db, &cfg, false, frange);
+        let assists = Assist::get(&db, &cfg, AssistResolveStrategy::None, frange);
         let expected = labels(&assists);
 
         expect![[r#""#]].assert_eq(&expected);
     }
 }
+
+#[test]
+fn various_resolve_strategies() {
+    let (db, frange) = RootDatabase::with_range(
+        r#"
+pub fn test_some_range(a: int) -> bool {
+    if let 2..6 = $05$0 {
+        true
+    } else {
+        false
+    }
+}
+"#,
+    );
+
+    let mut cfg = TEST_CONFIG;
+    cfg.allowed = Some(vec![AssistKind::RefactorExtract]);
+
+    {
+        let assists = Assist::get(&db, &cfg, AssistResolveStrategy::None, frange);
+        assert_eq!(2, assists.len());
+        let mut assists = assists.into_iter();
+
+        let extract_into_variable_assist = assists.next().unwrap();
+        expect![[r#"
+            Assist {
+                id: AssistId(
+                    "extract_variable",
+                    RefactorExtract,
+                ),
+                label: "Extract into variable",
+                group: None,
+                target: 59..60,
+                source_change: None,
+            }
+        "#]]
+        .assert_debug_eq(&extract_into_variable_assist);
+
+        let extract_into_function_assist = assists.next().unwrap();
+        expect![[r#"
+            Assist {
+                id: AssistId(
+                    "extract_function",
+                    RefactorExtract,
+                ),
+                label: "Extract into function",
+                group: None,
+                target: 59..60,
+                source_change: None,
+            }
+        "#]]
+        .assert_debug_eq(&extract_into_function_assist);
+    }
+
+    {
+        let assists = Assist::get(
+            &db,
+            &cfg,
+            AssistResolveStrategy::Single(SingleResolve {
+                assist_id: "SOMETHING_MISMATCHING".to_string(),
+                assist_kind: AssistKind::RefactorExtract,
+            }),
+            frange,
+        );
+        assert_eq!(2, assists.len());
+        let mut assists = assists.into_iter();
+
+        let extract_into_variable_assist = assists.next().unwrap();
+        expect![[r#"
+            Assist {
+                id: AssistId(
+                    "extract_variable",
+                    RefactorExtract,
+                ),
+                label: "Extract into variable",
+                group: None,
+                target: 59..60,
+                source_change: None,
+            }
+        "#]]
+        .assert_debug_eq(&extract_into_variable_assist);
+
+        let extract_into_function_assist = assists.next().unwrap();
+        expect![[r#"
+            Assist {
+                id: AssistId(
+                    "extract_function",
+                    RefactorExtract,
+                ),
+                label: "Extract into function",
+                group: None,
+                target: 59..60,
+                source_change: None,
+            }
+        "#]]
+        .assert_debug_eq(&extract_into_function_assist);
+    }
+
+    {
+        let assists = Assist::get(
+            &db,
+            &cfg,
+            AssistResolveStrategy::Single(SingleResolve {
+                assist_id: "extract_variable".to_string(),
+                assist_kind: AssistKind::RefactorExtract,
+            }),
+            frange,
+        );
+        assert_eq!(2, assists.len());
+        let mut assists = assists.into_iter();
+
+        let extract_into_variable_assist = assists.next().unwrap();
+        expect![[r#"
+            Assist {
+                id: AssistId(
+                    "extract_variable",
+                    RefactorExtract,
+                ),
+                label: "Extract into variable",
+                group: None,
+                target: 59..60,
+                source_change: Some(
+                    SourceChange {
+                        source_file_edits: {
+                            FileId(
+                                0,
+                            ): TextEdit {
+                                indels: [
+                                    Indel {
+                                        insert: "let $0var_name = 5;\n    ",
+                                        delete: 45..45,
+                                    },
+                                    Indel {
+                                        insert: "var_name",
+                                        delete: 59..60,
+                                    },
+                                ],
+                            },
+                        },
+                        file_system_edits: [],
+                        is_snippet: true,
+                    },
+                ),
+            }
+        "#]]
+        .assert_debug_eq(&extract_into_variable_assist);
+
+        let extract_into_function_assist = assists.next().unwrap();
+        expect![[r#"
+            Assist {
+                id: AssistId(
+                    "extract_function",
+                    RefactorExtract,
+                ),
+                label: "Extract into function",
+                group: None,
+                target: 59..60,
+                source_change: None,
+            }
+        "#]]
+        .assert_debug_eq(&extract_into_function_assist);
+    }
+
+    {
+        let assists = Assist::get(&db, &cfg, AssistResolveStrategy::All, frange);
+        assert_eq!(2, assists.len());
+        let mut assists = assists.into_iter();
+
+        let extract_into_variable_assist = assists.next().unwrap();
+        expect![[r#"
+            Assist {
+                id: AssistId(
+                    "extract_variable",
+                    RefactorExtract,
+                ),
+                label: "Extract into variable",
+                group: None,
+                target: 59..60,
+                source_change: Some(
+                    SourceChange {
+                        source_file_edits: {
+                            FileId(
+                                0,
+                            ): TextEdit {
+                                indels: [
+                                    Indel {
+                                        insert: "let $0var_name = 5;\n    ",
+                                        delete: 45..45,
+                                    },
+                                    Indel {
+                                        insert: "var_name",
+                                        delete: 59..60,
+                                    },
+                                ],
+                            },
+                        },
+                        file_system_edits: [],
+                        is_snippet: true,
+                    },
+                ),
+            }
+        "#]]
+        .assert_debug_eq(&extract_into_variable_assist);
+
+        let extract_into_function_assist = assists.next().unwrap();
+        expect![[r#"
+            Assist {
+                id: AssistId(
+                    "extract_function",
+                    RefactorExtract,
+                ),
+                label: "Extract into function",
+                group: None,
+                target: 59..60,
+                source_change: Some(
+                    SourceChange {
+                        source_file_edits: {
+                            FileId(
+                                0,
+                            ): TextEdit {
+                                indels: [
+                                    Indel {
+                                        insert: "fun_name()",
+                                        delete: 59..60,
+                                    },
+                                    Indel {
+                                        insert: "\n\nfn $0fun_name() -> i32 {\n    5\n}",
+                                        delete: 110..110,
+                                    },
+                                ],
+                            },
+                        },
+                        file_system_edits: [],
+                        is_snippet: true,
+                    },
+                ),
+            }
+        "#]]
+        .assert_debug_eq(&extract_into_function_assist);
+    }
+}
diff --git a/crates/ide_assists/src/utils/suggest_name.rs b/crates/ide_assists/src/utils/suggest_name.rs
index 533624c1f..deafcd630 100644
--- a/crates/ide_assists/src/utils/suggest_name.rs
+++ b/crates/ide_assists/src/utils/suggest_name.rs
@@ -227,7 +227,7 @@ fn name_of_type(ty: &hir::Type, db: &RootDatabase) -> Option<String> {
         let name = adt.name(db).to_string();
 
         if WRAPPER_TYPES.contains(&name.as_str()) {
-            let inner_ty = ty.type_parameters().next()?;
+            let inner_ty = ty.type_arguments().next()?;
             return name_of_type(&inner_ty, db);
         }