Add expression fill mode variant for filling with underscore expressions

Author: Veykril

src/tools/rust-analyzer/crates/hir-def/src/nameres/mod_resolution.rs

@@ -86,7 +86,7 @@ impl ModDir {
                 let dir_path = if root_dir_owner {
                     DirPath::empty()
                 } else {
-                    DirPath::new(format!("{}/", name))
+                    DirPath::new(format!("{name}/"))
                 };
                 if let Some(mod_dir) = self.child(dir_path, !root_dir_owner) {
                     return Ok((

src/tools/rust-analyzer/crates/hir-expand/src/db.rs

@@ -752,8 +752,7 @@ fn check_tt_count(tt: &tt::TopSubtree) -> Result<(), ExpandResult<()>> {
             err: Some(ExpandError::other(
                 tt.delimiter.open,
                 format!(
-                    "macro invocation exceeds token limit: produced {} tokens, limit is {}",
-                    count, TOKEN_LIMIT,
+                    "macro invocation exceeds token limit: produced {count} tokens, limit is {TOKEN_LIMIT}",
                 ),
             )),
         })

src/tools/rust-analyzer/crates/hir-expand/src/lib.rs

@@ -206,8 +206,7 @@ impl ExpandErrorKind {
                     },
                     None => RenderedExpandError {
                         message: format!(
-                            "internal error: proc-macro map is missing error entry for crate {:?}",
-                            def_crate
+                            "internal error: proc-macro map is missing error entry for crate {def_crate:?}"
                         ),
                         error: true,
                         kind: RenderedExpandError::GENERAL_KIND,

src/tools/rust-analyzer/crates/ide-assists/src/assist_config.rs

@@ -5,7 +5,7 @@
 //! assists if we are allowed to.
 
 use hir::ImportPathConfig;
-use ide_db::{SnippetCap, imports::insert_use::InsertUseConfig};
+use ide_db::{SnippetCap, assists::ExprFillDefaultMode, imports::insert_use::InsertUseConfig};
 
 use crate::AssistKind;
 
@@ -21,6 +21,7 @@ pub struct AssistConfig {
     pub term_search_fuel: u64,
     pub term_search_borrowck: bool,
     pub code_action_grouping: bool,
+    pub expr_fill_default: ExprFillDefaultMode,
 }
 
 impl AssistConfig {

src/tools/rust-analyzer/crates/ide-assists/src/handlers/add_missing_impl_members.rs

@@ -150,6 +150,7 @@ fn add_missing_impl_members_inner(
         let new_impl_def = edit.make_mut(impl_def.clone());
         let first_new_item = add_trait_assoc_items_to_impl(
             &ctx.sema,
+            ctx.config,
             &missing_items,
             trait_,
             &new_impl_def,

src/tools/rust-analyzer/crates/ide-assists/src/handlers/add_missing_match_arms.rs

@@ -3,6 +3,7 @@ use std::iter::{self, Peekable};
 use either::Either;
 use hir::{Adt, Crate, HasAttrs, ImportPathConfig, ModuleDef, Semantics, sym};
 use ide_db::RootDatabase;
+use ide_db::assists::ExprFillDefaultMode;
 use ide_db::syntax_helpers::suggest_name;
 use ide_db::{famous_defs::FamousDefs, helpers::mod_path_to_ast};
 use itertools::Itertools;
@@ -216,7 +217,17 @@ pub(crate) fn add_missing_match_arms(acc: &mut Assists, ctx: &AssistContext<'_>)
                     // filter out hidden patterns because they're handled by the catch-all arm
                     !hidden
                 })
-                .map(|(pat, _)| make.match_arm(pat, None, make::ext::expr_todo()));
+                .map(|(pat, _)| {
+                    make.match_arm(
+                        pat,
+                        None,
+                        match ctx.config.expr_fill_default {
+                            ExprFillDefaultMode::Todo => make::ext::expr_todo(),
+                            ExprFillDefaultMode::Underscore => make::ext::expr_underscore(),
+                            ExprFillDefaultMode::Default => make::ext::expr_todo(),
+                        },
+                    )
+                });
 
             let mut arms: Vec<_> = match_arm_list
                 .arms()
@@ -246,7 +257,15 @@ pub(crate) fn add_missing_match_arms(acc: &mut Assists, ctx: &AssistContext<'_>)
 
             if needs_catch_all_arm && !has_catch_all_arm {
                 cov_mark::hit!(added_wildcard_pattern);
-                let arm = make.match_arm(make.wildcard_pat().into(), None, make::ext::expr_todo());
+                let arm = make.match_arm(
+                    make.wildcard_pat().into(),
+                    None,
+                    match ctx.config.expr_fill_default {
+                        ExprFillDefaultMode::Todo => make::ext::expr_todo(),
+                        ExprFillDefaultMode::Underscore => make::ext::expr_underscore(),
+                        ExprFillDefaultMode::Default => make::ext::expr_todo(),
+                    },
+                );
                 arms.push(arm);
             }
 

src/tools/rust-analyzer/crates/ide-assists/src/handlers/destructure_tuple_binding.rs

@@ -142,7 +142,7 @@ fn collect_data(ident_pat: IdentPat, ctx: &AssistContext<'_>) -> Option<TupleDat
         .map(|(id, ty)| {
             match name_generator.for_type(&ty, ctx.db(), ctx.edition()) {
                 Some(name) => name,
-                None => name_generator.suggest_name(&format!("_{}", id)),
+                None => name_generator.suggest_name(&format!("_{id}")),
             }
             .to_string()
         })

src/tools/rust-analyzer/crates/ide-assists/src/handlers/generate_function.rs

@@ -4,6 +4,7 @@ use hir::{
 };
 use ide_db::{
     FileId, FxHashMap, FxHashSet, RootDatabase, SnippetCap,
+    assists::ExprFillDefaultMode,
     defs::{Definition, NameRefClass},
     famous_defs::FamousDefs,
     helpers::is_editable_crate,
@@ -276,7 +277,11 @@ impl FunctionBuilder {
                 target_module,
                 &mut necessary_generic_params,
             );
-            let placeholder_expr = make::ext::expr_todo();
+            let placeholder_expr = match ctx.config.expr_fill_default {
+                ExprFillDefaultMode::Todo => make::ext::expr_todo(),
+                ExprFillDefaultMode::Underscore => make::ext::expr_underscore(),
+                ExprFillDefaultMode::Default => make::ext::expr_todo(),
+            };
             fn_body = make::block_expr(vec![], Some(placeholder_expr));
         };
 
@@ -331,7 +336,11 @@ impl FunctionBuilder {
         let (generic_param_list, where_clause) =
             fn_generic_params(ctx, necessary_generic_params, &target)?;
 
-        let placeholder_expr = make::ext::expr_todo();
+        let placeholder_expr = match ctx.config.expr_fill_default {
+            ExprFillDefaultMode::Todo => make::ext::expr_todo(),
+            ExprFillDefaultMode::Underscore => make::ext::expr_underscore(),
+            ExprFillDefaultMode::Default => make::ext::expr_todo(),
+        };
         let fn_body = make::block_expr(vec![], Some(placeholder_expr));
 
         Some(Self {
@@ -444,7 +453,11 @@ fn make_fn_body_as_new_function(
     let adt_info = adt_info.as_ref()?;
 
     let path_self = make::ext::ident_path("Self");
-    let placeholder_expr = make::ext::expr_todo();
+    let placeholder_expr = match ctx.config.expr_fill_default {
+        ExprFillDefaultMode::Todo => make::ext::expr_todo(),
+        ExprFillDefaultMode::Underscore => make::ext::expr_underscore(),
+        ExprFillDefaultMode::Default => make::ext::expr_todo(),
+    };
     let tail_expr = if let Some(strukt) = adt_info.adt.as_struct() {
         match strukt.kind(ctx.db()) {
             StructKind::Record => {

src/tools/rust-analyzer/crates/ide-assists/src/handlers/replace_derive_with_manual_impl.rs

@@ -9,7 +9,7 @@ use syntax::{
 };
 
 use crate::{
-    AssistId,
+    AssistConfig, AssistId,
     assist_context::{AssistContext, Assists, SourceChangeBuilder},
     utils::{
         DefaultMethods, IgnoreAssocItems, add_trait_assoc_items_to_impl, filter_assoc_items,
@@ -128,8 +128,14 @@ fn add_assist(
     acc.add(AssistId::refactor("replace_derive_with_manual_impl"), label, target, |builder| {
         let insert_after = ted::Position::after(builder.make_mut(adt.clone()).syntax());
         let impl_is_unsafe = trait_.map(|s| s.is_unsafe(ctx.db())).unwrap_or(false);
-        let impl_def_with_items =
-            impl_def_from_trait(&ctx.sema, adt, &annotated_name, trait_, replace_trait_path);
+        let impl_def_with_items = impl_def_from_trait(
+            &ctx.sema,
+            ctx.config,
+            adt,
+            &annotated_name,
+            trait_,
+            replace_trait_path,
+        );
         update_attribute(builder, old_derives, old_tree, old_trait_path, attr);
 
         let trait_path = make::ty_path(replace_trait_path.clone());
@@ -217,6 +223,7 @@ fn add_assist(
 
 fn impl_def_from_trait(
     sema: &hir::Semantics<'_, ide_db::RootDatabase>,
+    config: &AssistConfig,
     adt: &ast::Adt,
     annotated_name: &ast::Name,
     trait_: Option<hir::Trait>,
@@ -241,7 +248,7 @@ fn impl_def_from_trait(
     let impl_def = generate_trait_impl(adt, make::ty_path(trait_path.clone()));
 
     let first_assoc_item =
-        add_trait_assoc_items_to_impl(sema, &trait_items, trait_, &impl_def, &target_scope);
+        add_trait_assoc_items_to_impl(sema, config, &trait_items, trait_, &impl_def, &target_scope);
 
     // Generate a default `impl` function body for the derived trait.
     if let ast::AssocItem::Fn(ref func) = first_assoc_item {

src/tools/rust-analyzer/crates/ide-assists/src/tests.rs

@@ -4,6 +4,7 @@ use expect_test::expect;
 use hir::Semantics;
 use ide_db::{
     EditionedFileId, FileRange, RootDatabase, SnippetCap,
+    assists::ExprFillDefaultMode,
     base_db::SourceDatabase,
     imports::insert_use::{ImportGranularity, InsertUseConfig},
     source_change::FileSystemEdit,
@@ -35,6 +36,7 @@ pub(crate) const TEST_CONFIG: AssistConfig = AssistConfig {
     term_search_fuel: 400,
     term_search_borrowck: true,
     code_action_grouping: true,
+    expr_fill_default: ExprFillDefaultMode::Todo,
 };
 
 pub(crate) const TEST_CONFIG_NO_GROUPING: AssistConfig = AssistConfig {
@@ -54,6 +56,7 @@ pub(crate) const TEST_CONFIG_NO_GROUPING: AssistConfig = AssistConfig {
     term_search_fuel: 400,
     term_search_borrowck: true,
     code_action_grouping: false,
+    expr_fill_default: ExprFillDefaultMode::Todo,
 };
 
 pub(crate) const TEST_CONFIG_NO_SNIPPET_CAP: AssistConfig = AssistConfig {
@@ -73,6 +76,7 @@ pub(crate) const TEST_CONFIG_NO_SNIPPET_CAP: AssistConfig = AssistConfig {
     term_search_fuel: 400,
     term_search_borrowck: true,
     code_action_grouping: true,
+    expr_fill_default: ExprFillDefaultMode::Todo,
 };
 
 pub(crate) const TEST_CONFIG_IMPORT_ONE: AssistConfig = AssistConfig {
@@ -92,6 +96,7 @@ pub(crate) const TEST_CONFIG_IMPORT_ONE: AssistConfig = AssistConfig {
     term_search_fuel: 400,
     term_search_borrowck: true,
     code_action_grouping: true,
+    expr_fill_default: ExprFillDefaultMode::Todo,
 };
 
 pub(crate) fn with_single_file(text: &str) -> (RootDatabase, EditionedFileId) {