move trait body gen code to utils

crates/ide_assists/src/handlers/replace_derive_with_manual_impl.rs

@@ -2,13 +2,12 @@ use hir::ModuleDef;
 use ide_db::helpers::{import_assets::NameToImport, mod_path_to_ast};
 use ide_db::items_locator;
 use itertools::Itertools;
-use syntax::ast::edit::AstNodeEdit;
-use syntax::ted;
 use syntax::{
     ast::{self, make, AstNode, NameOwner},
     SyntaxKind::{IDENT, WHITESPACE},
 };
 
+use crate::utils::gen_trait_body;
 use crate::{
     assist_context::{AssistBuilder, AssistContext, Assists},
     utils::{
@@ -169,158 +168,12 @@ fn impl_def_from_trait(
 
     // Generate a default `impl` function body for the derived trait.
     if let ast::AssocItem::Fn(ref func) = first_assoc_item {
-        let _ = gen_trait_body_impl(func, trait_path, adt, annotated_name);
+        let _ = gen_trait_body(func, trait_path, adt, annotated_name);
     };
 
     Some((impl_def, first_assoc_item))
 }
 
-/// Generate custom trait bodies where possible.
-///
-/// Returns `Option` so that we can use `?` rather than `if let Some`. Returning
-/// `None` means that generating a custom trait body failed, and the body will remain
-/// as `todo!` instead.
-fn gen_trait_body_impl(
-    func: &ast::Fn,
-    trait_path: &ast::Path,
-    adt: &ast::Adt,
-    annotated_name: &ast::Name,
-) -> Option<()> {
-    match trait_path.segment()?.name_ref()?.text().as_str() {
-        "Debug" => gen_debug_impl(adt, func, annotated_name),
-        "Default" => gen_default_impl(adt, func),
-        _ => None,
-    }
-}
-
-/// Generate a `Debug` impl based on the fields and members of the target type.
-fn gen_debug_impl(adt: &ast::Adt, func: &ast::Fn, annotated_name: &ast::Name) -> Option<()> {
-    match adt {
-        // `Debug` cannot be derived for unions, so no default impl can be provided.
-        ast::Adt::Union(_) => None,
-
-        // => match self { Self::Variant => write!(f, "Variant") }
-        ast::Adt::Enum(enum_) => {
-            let list = enum_.variant_list()?;
-            let mut arms = vec![];
-            for variant in list.variants() {
-                let name = variant.name()?;
-                let left = make::ext::ident_path("Self");
-                let right = make::ext::ident_path(&format!("{}", name));
-                let variant_name = make::path_pat(make::path_concat(left, right));
-
-                let target = make::expr_path(make::ext::ident_path("f").into());
-                let fmt_string = make::expr_literal(&(format!("\"{}\"", name))).into();
-                let args = make::arg_list(vec![target, fmt_string]);
-                let macro_name = make::expr_path(make::ext::ident_path("write"));
-                let macro_call = make::expr_macro_call(macro_name, args);
-
-                arms.push(make::match_arm(Some(variant_name.into()), None, macro_call.into()));
-            }
-
-            let match_target = make::expr_path(make::ext::ident_path("self"));
-            let list = make::match_arm_list(arms).indent(ast::edit::IndentLevel(1));
-            let match_expr = make::expr_match(match_target, list);
-
-            let body = make::block_expr(None, Some(match_expr));
-            let body = body.indent(ast::edit::IndentLevel(1));
-            ted::replace(func.body()?.syntax(), body.clone_for_update().syntax());
-            Some(())
-        }
-
-        ast::Adt::Struct(strukt) => {
-            let name = format!("\"{}\"", annotated_name);
-            let args = make::arg_list(Some(make::expr_literal(&name).into()));
-            let target = make::expr_path(make::ext::ident_path("f"));
-
-            let expr = match strukt.field_list() {
-                // => f.debug_struct("Name").finish()
-                None => make::expr_method_call(target, make::name_ref("debug_struct"), args),
-
-                // => f.debug_struct("Name").field("foo", &self.foo).finish()
-                Some(ast::FieldList::RecordFieldList(field_list)) => {
-                    let method = make::name_ref("debug_struct");
-                    let mut expr = make::expr_method_call(target, method, args);
-                    for field in field_list.fields() {
-                        let name = field.name()?;
-                        let f_name = make::expr_literal(&(format!("\"{}\"", name))).into();
-                        let f_path = make::expr_path(make::ext::ident_path("self"));
-                        let f_path = make::expr_ref(f_path, false);
-                        let f_path = make::expr_field(f_path, &format!("{}", name)).into();
-                        let args = make::arg_list(vec![f_name, f_path]);
-                        expr = make::expr_method_call(expr, make::name_ref("field"), args);
-                    }
-                    expr
-                }
-
-                // => f.debug_tuple("Name").field(self.0).finish()
-                Some(ast::FieldList::TupleFieldList(field_list)) => {
-                    let method = make::name_ref("debug_tuple");
-                    let mut expr = make::expr_method_call(target, method, args);
-                    for (idx, _) in field_list.fields().enumerate() {
-                        let f_path = make::expr_path(make::ext::ident_path("self"));
-                        let f_path = make::expr_ref(f_path, false);
-                        let f_path = make::expr_field(f_path, &format!("{}", idx)).into();
-                        let method = make::name_ref("field");
-                        expr = make::expr_method_call(expr, method, make::arg_list(Some(f_path)));
-                    }
-                    expr
-                }
-            };
-
-            let method = make::name_ref("finish");
-            let expr = make::expr_method_call(expr, method, make::arg_list(None));
-            let body = make::block_expr(None, Some(expr)).indent(ast::edit::IndentLevel(1));
-            ted::replace(func.body()?.syntax(), body.clone_for_update().syntax());
-            Some(())
-        }
-    }
-}
-
-/// Generate a `Debug` impl based on the fields and members of the target type.
-fn gen_default_impl(adt: &ast::Adt, func: &ast::Fn) -> Option<()> {
-    fn gen_default_call() -> ast::Expr {
-        let trait_name = make::ext::ident_path("Default");
-        let method_name = make::ext::ident_path("default");
-        let fn_name = make::expr_path(make::path_concat(trait_name, method_name));
-        make::expr_call(fn_name, make::arg_list(None))
-    }
-    match adt {
-        // `Debug` cannot be derived for unions, so no default impl can be provided.
-        ast::Adt::Union(_) => None,
-        // Deriving `Debug` for enums is not stable yet.
-        ast::Adt::Enum(_) => None,
-        ast::Adt::Struct(strukt) => {
-            let expr = match strukt.field_list() {
-                Some(ast::FieldList::RecordFieldList(field_list)) => {
-                    let mut fields = vec![];
-                    for field in field_list.fields() {
-                        let method_call = gen_default_call();
-                        let name_ref = make::name_ref(&field.name()?.to_string());
-                        let field = make::record_expr_field(name_ref, Some(method_call));
-                        fields.push(field);
-                    }
-                    let struct_name = make::ext::ident_path("Self");
-                    let fields = make::record_expr_field_list(fields);
-                    make::record_expr(struct_name, fields).into()
-                }
-                Some(ast::FieldList::TupleFieldList(field_list)) => {
-                    let struct_name = make::expr_path(make::ext::ident_path("Self"));
-                    let fields = field_list.fields().map(|_| gen_default_call());
-                    make::expr_call(struct_name, make::arg_list(fields))
-                }
-                None => {
-                    let struct_name = make::ext::ident_path("Self");
-                    let fields = make::record_expr_field_list(None);
-                    make::record_expr(struct_name, fields).into()
-                }
-            };
-            let body = make::block_expr(None, Some(expr)).indent(ast::edit::IndentLevel(1));
-            ted::replace(func.body()?.syntax(), body.clone_for_update().syntax());
-            Some(())
-        }
-    }
-}
 fn update_attribute(
     builder: &mut AssistBuilder,
     input: &ast::TokenTree,

crates/ide_assists/src/utils.rs

@@ -1,6 +1,7 @@
 //! Assorted functions shared by several assists.
 
 pub(crate) mod suggest_name;
+mod gen_trait_body;
 
 use std::ops;
 
@@ -25,6 +26,8 @@ use syntax::{
 
 use crate::assist_context::{AssistBuilder, AssistContext};
 
+pub(crate) use gen_trait_body::gen_trait_body;
+
 pub(crate) fn unwrap_trivial_block(block: ast::BlockExpr) -> ast::Expr {
     extract_trivial_expression(&block)
         .filter(|expr| !expr.syntax().text().contains_char('\n'))

crates/ide_assists/src/utils/gen_trait_body.rs

@@ -0,0 +1,149 @@
+use syntax::ast::{self, edit::AstNodeEdit, make, AstNode, NameOwner};
+use syntax::ted;
+
+/// Generate custom trait bodies where possible.
+///
+/// Returns `Option` so that we can use `?` rather than `if let Some`. Returning
+/// `None` means that generating a custom trait body failed, and the body will remain
+/// as `todo!` instead.
+pub(crate) fn gen_trait_body(
+    func: &ast::Fn,
+    trait_path: &ast::Path,
+    adt: &ast::Adt,
+    annotated_name: &ast::Name,
+) -> Option<()> {
+    match trait_path.segment()?.name_ref()?.text().as_str() {
+        "Debug" => gen_debug_impl(adt, func, annotated_name),
+        "Default" => gen_default_impl(adt, func),
+        _ => None,
+    }
+}
+
+/// Generate a `Debug` impl based on the fields and members of the target type.
+fn gen_debug_impl(adt: &ast::Adt, func: &ast::Fn, annotated_name: &ast::Name) -> Option<()> {
+    match adt {
+        // `Debug` cannot be derived for unions, so no default impl can be provided.
+        ast::Adt::Union(_) => None,
+
+        // => match self { Self::Variant => write!(f, "Variant") }
+        ast::Adt::Enum(enum_) => {
+            let list = enum_.variant_list()?;
+            let mut arms = vec![];
+            for variant in list.variants() {
+                let name = variant.name()?;
+                let left = make::ext::ident_path("Self");
+                let right = make::ext::ident_path(&format!("{}", name));
+                let variant_name = make::path_pat(make::path_concat(left, right));
+
+                let target = make::expr_path(make::ext::ident_path("f").into());
+                let fmt_string = make::expr_literal(&(format!("\"{}\"", name))).into();
+                let args = make::arg_list(vec![target, fmt_string]);
+                let macro_name = make::expr_path(make::ext::ident_path("write"));
+                let macro_call = make::expr_macro_call(macro_name, args);
+
+                arms.push(make::match_arm(Some(variant_name.into()), None, macro_call.into()));
+            }
+
+            let match_target = make::expr_path(make::ext::ident_path("self"));
+            let list = make::match_arm_list(arms).indent(ast::edit::IndentLevel(1));
+            let match_expr = make::expr_match(match_target, list);
+
+            let body = make::block_expr(None, Some(match_expr));
+            let body = body.indent(ast::edit::IndentLevel(1));
+            ted::replace(func.body()?.syntax(), body.clone_for_update().syntax());
+            Some(())
+        }
+
+        ast::Adt::Struct(strukt) => {
+            let name = format!("\"{}\"", annotated_name);
+            let args = make::arg_list(Some(make::expr_literal(&name).into()));
+            let target = make::expr_path(make::ext::ident_path("f"));
+
+            let expr = match strukt.field_list() {
+                // => f.debug_struct("Name").finish()
+                None => make::expr_method_call(target, make::name_ref("debug_struct"), args),
+
+                // => f.debug_struct("Name").field("foo", &self.foo).finish()
+                Some(ast::FieldList::RecordFieldList(field_list)) => {
+                    let method = make::name_ref("debug_struct");
+                    let mut expr = make::expr_method_call(target, method, args);
+                    for field in field_list.fields() {
+                        let name = field.name()?;
+                        let f_name = make::expr_literal(&(format!("\"{}\"", name))).into();
+                        let f_path = make::expr_path(make::ext::ident_path("self"));
+                        let f_path = make::expr_ref(f_path, false);
+                        let f_path = make::expr_field(f_path, &format!("{}", name)).into();
+                        let args = make::arg_list(vec![f_name, f_path]);
+                        expr = make::expr_method_call(expr, make::name_ref("field"), args);
+                    }
+                    expr
+                }
+
+                // => f.debug_tuple("Name").field(self.0).finish()
+                Some(ast::FieldList::TupleFieldList(field_list)) => {
+                    let method = make::name_ref("debug_tuple");
+                    let mut expr = make::expr_method_call(target, method, args);
+                    for (idx, _) in field_list.fields().enumerate() {
+                        let f_path = make::expr_path(make::ext::ident_path("self"));
+                        let f_path = make::expr_ref(f_path, false);
+                        let f_path = make::expr_field(f_path, &format!("{}", idx)).into();
+                        let method = make::name_ref("field");
+                        expr = make::expr_method_call(expr, method, make::arg_list(Some(f_path)));
+                    }
+                    expr
+                }
+            };
+
+            let method = make::name_ref("finish");
+            let expr = make::expr_method_call(expr, method, make::arg_list(None));
+            let body = make::block_expr(None, Some(expr)).indent(ast::edit::IndentLevel(1));
+            ted::replace(func.body()?.syntax(), body.clone_for_update().syntax());
+            Some(())
+        }
+    }
+}
+
+/// Generate a `Debug` impl based on the fields and members of the target type.
+fn gen_default_impl(adt: &ast::Adt, func: &ast::Fn) -> Option<()> {
+    fn gen_default_call() -> ast::Expr {
+        let trait_name = make::ext::ident_path("Default");
+        let method_name = make::ext::ident_path("default");
+        let fn_name = make::expr_path(make::path_concat(trait_name, method_name));
+        make::expr_call(fn_name, make::arg_list(None))
+    }
+    match adt {
+        // `Debug` cannot be derived for unions, so no default impl can be provided.
+        ast::Adt::Union(_) => None,
+        // Deriving `Debug` for enums is not stable yet.
+        ast::Adt::Enum(_) => None,
+        ast::Adt::Struct(strukt) => {
+            let expr = match strukt.field_list() {
+                Some(ast::FieldList::RecordFieldList(field_list)) => {
+                    let mut fields = vec![];
+                    for field in field_list.fields() {
+                        let method_call = gen_default_call();
+                        let name_ref = make::name_ref(&field.name()?.to_string());
+                        let field = make::record_expr_field(name_ref, Some(method_call));
+                        fields.push(field);
+                    }
+                    let struct_name = make::ext::ident_path("Self");
+                    let fields = make::record_expr_field_list(fields);
+                    make::record_expr(struct_name, fields).into()
+                }
+                Some(ast::FieldList::TupleFieldList(field_list)) => {
+                    let struct_name = make::expr_path(make::ext::ident_path("Self"));
+                    let fields = field_list.fields().map(|_| gen_default_call());
+                    make::expr_call(struct_name, make::arg_list(fields))
+                }
+                None => {
+                    let struct_name = make::ext::ident_path("Self");
+                    let fields = make::record_expr_field_list(None);
+                    make::record_expr(struct_name, fields).into()
+                }
+            };
+            let body = make::block_expr(None, Some(expr)).indent(ast::edit::IndentLevel(1));
+            ted::replace(func.body()?.syntax(), body.clone_for_update().syntax());
+            Some(())
+        }
+    }
+}