rust-analyzer

diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs
index 6306ae534d..8d5dbd28ac 100644
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs

@@ -1685,6 +1685,26 @@ impl BuiltinType {

pub fn name(self) -> Name {

self.inner.as_name()

}

+ pub fn is_int(&self) -> bool {

+ matches!(self.inner, hir_def::builtin_type::BuiltinType::Int(_))

+ }

+ pub fn is_uint(&self) -> bool {

+ matches!(self.inner, hir_def::builtin_type::BuiltinType::Uint(_))

+ }

+ pub fn is_float(&self) -> bool {

+ matches!(self.inner, hir_def::builtin_type::BuiltinType::Float(_))

+ }

+ pub fn is_char(&self) -> bool {

+ matches!(self.inner, hir_def::builtin_type::BuiltinType::Char)

+ }

+ pub fn is_str(&self) -> bool {

+ matches!(self.inner, hir_def::builtin_type::BuiltinType::Str)

+ }

}

#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]

@@ -2573,6 +2593,10 @@ impl Type {

matches!(&self.ty.kind(Interner), TyKind::FnDef(..) | TyKind::Function { .. })

}

+ pub fn is_array(&self) -> bool {

+ matches!(&self.ty.kind(Interner), TyKind::Array(..))

+ }

pub fn is_packed(&self, db: &dyn HirDatabase) -> bool {

let adt_id = match *self.ty.kind(Interner) {

TyKind::Adt(hir_ty::AdtId(adt_id), ..) => adt_id,

diff --git a/crates/hir_expand/src/name.rs b/crates/hir_expand/src/name.rs
index 23f81d3c7f..3636ab6213 100644
--- a/crates/hir_expand/src/name.rs
+++ b/crates/hir_expand/src/name.rs

@@ -226,6 +226,7 @@ pub mod known {

iter_mut,

len,

is_empty,

+ new,

// Builtin macros

asm,

assert,

diff --git a/crates/ide_diagnostics/src/handlers/missing_fields.rs b/crates/ide_diagnostics/src/handlers/missing_fields.rs
index b5860fb858..cded84c54e 100644
--- a/crates/ide_diagnostics/src/handlers/missing_fields.rs
+++ b/crates/ide_diagnostics/src/handlers/missing_fields.rs

@@ -1,9 +1,16 @@

use either::Either;

-use hir::{db::AstDatabase, InFile, Type};

+use hir::{

+ db::{AstDatabase, HirDatabase},

+ known, HirDisplay, InFile, SemanticsScope, Type,

+};

use ide_db::{assists::Assist, helpers::FamousDefs, source_change::SourceChange};

use rustc_hash::FxHashMap;

use stdx::format_to;

-use syntax::{algo, ast::make, AstNode, SyntaxNodePtr};

+use syntax::{

+ algo,

+ ast::{self, make},

+ AstNode, SyntaxNodePtr,

+};

use text_edit::TextEdit;

use crate::{fix, Diagnostic, DiagnosticsContext};

@@ -67,13 +74,10 @@ fn fixes(ctx: &DiagnosticsContext<'_>, d: &hir::MissingFields) -> Option<Vec<Ass

let generate_fill_expr = |ty: &Type| match ctx.config.expr_fill_default {

crate::ExprFillDefaultMode::Todo => Some(make::ext::expr_todo()),

crate::ExprFillDefaultMode::DefaultImpl => {

- let krate = ctx.sema.to_module_def(d.file.original_file(ctx.sema.db))?.krate();

- let default_trait = FamousDefs(&ctx.sema, Some(krate)).core_default_Default();

- match default_trait {

- Some(default_trait) if ty.impls_trait(ctx.sema.db, default_trait, &[]) => {

- Some(make::ext::expr_default())

- }

+ let scope = ctx.sema.scope(&root);

+ let default_constr = get_default_constructor(ctx, d, &scope, ty);

+ match default_constr {

+ Some(default_constr) => Some(default_constr),

_ => Some(make::ext::expr_todo()),

}

@@ -118,6 +122,68 @@ fn fixes(ctx: &DiagnosticsContext<'_>, d: &hir::MissingFields) -> Option<Vec<Ass

)])

}

+fn make_ty(ty: &hir::Type, db: &dyn HirDatabase, module: hir::Module) -> ast::Type {

+ let ty_str = match ty.as_adt() {

+ Some(adt) => adt.name(db).to_string(),

+ None => ty.display_source_code(db, module.into()).ok().unwrap_or_else(|| "_".to_string()),

+ };

+ make::ty(&ty_str)

+fn get_default_constructor(

+ ctx: &DiagnosticsContext<'_>,

+ d: &hir::MissingFields,

+ scope: &SemanticsScope,

+ ty: &Type,

+) -> Option<ast::Expr> {

+ if let Some(builtin_ty) = ty.as_builtin() {

+ if builtin_ty.is_int() || builtin_ty.is_uint() {

+ return Some(make::ext::zero_number());

+ }

+ if builtin_ty.is_float() {

+ return Some(make::ext::zero_float());

+ }

+ if builtin_ty.is_char() {

+ return Some(make::ext::empty_char());

+ }

+ if builtin_ty.is_str() {

+ return Some(make::ext::empty_str());

+ }

+ let krate = ctx.sema.to_module_def(d.file.original_file(ctx.sema.db))?.krate();

+ let module = krate.root_module(ctx.sema.db);

+ let default_trait = FamousDefs(&ctx.sema, Some(krate)).core_default_Default()?;

+ let traits_in_scope = scope.visible_traits();

+ // Look for a ::new() method

+ // FIXME: doesn't work for now

+ let has_new_method = ty

+ .iterate_method_candidates(

+ ctx.sema.db,

+ krate,

+ &traits_in_scope,

+ Some(&known::new),

+ |_, func| {

+ if func.assoc_fn_params(ctx.sema.db).is_empty()

+ && func.self_param(ctx.sema.db).is_none()

+ {

+ return Some(());

+ }

+ None

+ },

+ )

+ .is_some();

+ if has_new_method {

+ Some(make::ext::expr_ty_new(&make_ty(ty, ctx.sema.db, module)))

+ } else if !ty.is_array() && ty.impls_trait(ctx.sema.db, default_trait, &[]) {

+ Some(make::ext::expr_ty_default(&make_ty(ty, ctx.sema.db, module)))

+ } else {

+ None

+ }

#[cfg(test)]

mod tests {

use crate::tests::{check_diagnostics, check_fix};

diff --git a/crates/rust-analyzer/src/config.rs b/crates/rust-analyzer/src/config.rs
index 9cef558457..2d4d24e98d 100644
--- a/crates/rust-analyzer/src/config.rs
+++ b/crates/rust-analyzer/src/config.rs

@@ -1273,7 +1273,7 @@ fn field_props(field: &str, ty: &str, doc: &[&str], default: &str) -> serde_json

"enum": ["todo", "defaultImpl"],

"enumDescriptions": [

"Fill missing elements with 'todo' macro",

- "Fill missing elements with Default::default()"

+ "Fill missing elements with T::default()"

"ImportGranularityDef" => set! {

diff --git a/crates/syntax/src/ast/make.rs b/crates/syntax/src/ast/make.rs
index 1a46b84c96..12d5b7decc 100644
--- a/crates/syntax/src/ast/make.rs
+++ b/crates/syntax/src/ast/make.rs

@@ -59,8 +59,27 @@ pub mod ext {

pub fn expr_todo() -> ast::Expr {

expr_from_text("todo!()")

}

- pub fn expr_default() -> ast::Expr {

- expr_from_text("Default::default()")

+ pub fn expr_ty_default(ty: &ast::Type) -> ast::Expr {

+ expr_from_text(&format!("{}::default()", ty))

+ }

+ pub fn expr_ty_new(ty: &ast::Type) -> ast::Expr {

+ expr_from_text(&format!("{}::new()", ty))

+ }

+ pub fn zero_number() -> ast::Expr {

+ expr_from_text("0")

+ }

+ pub fn zero_float() -> ast::Expr {

+ expr_from_text("0.0")

+ }

+ pub fn empty_str() -> ast::Expr {

+ expr_from_text(r#""""#)

+ }

+ pub fn empty_char() -> ast::Expr {

+ expr_from_text("''")

+ }

+ pub fn default_bool() -> ast::Expr {

+ expr_from_text("false")

}

pub fn empty_block_expr() -> ast::BlockExpr {

block_expr(None, None)

diff --git a/editors/code/package.json b/editors/code/package.json
index cbe9bf5442..6bc62fc9d7 100644
--- a/editors/code/package.json
+++ b/editors/code/package.json

@@ -388,7 +388,7 @@

"enumDescriptions": [

"Fill missing elements with 'todo' macro",

- "Fill missing elements with Default::default()"

+ "Fill missing elements with T::default()"

]

"rust-analyzer.assist.importGranularity": {