From 4b7ae9fedc2154a31f04400babb1dd0a93dffd16 Mon Sep 17 00:00:00 2001
From: Yoshua Wuyts <yoshuawuyts@gmail.com>
Date: Sun, 8 Aug 2021 15:24:04 +0200
Subject: [PATCH] generate Debug for enums
---
.../replace_derive_with_manual_impl.rs | 78 ++++++++++++++++++-
crates/syntax/src/ast/make.rs | 3 +
2 files changed, 80 insertions(+), 1 deletion(-)
diff --git a/crates/ide_assists/src/handlers/replace_derive_with_manual_impl.rs b/crates/ide_assists/src/handlers/replace_derive_with_manual_impl.rs
index e0319adccc6..8c3a5d25d9b 100644
--- a/crates/ide_assists/src/handlers/replace_derive_with_manual_impl.rs
+++ b/crates/ide_assists/src/handlers/replace_derive_with_manual_impl.rs
@@ -181,7 +181,37 @@ fn impl_def_from_trait(
fn gen_debug_impl(adt: &ast::Adt, func: &ast::Fn, annotated_name: &ast::Name) {
match adt {
ast::Adt::Union(_) => {} // `Debug` cannot be derived for unions, so no default impl can be provided.
- ast::Adt::Enum(enum_) => {} // TODO
+ ast::Adt::Enum(enum_) => {
+ if let Some(list) = enum_.variant_list() {
+ let mut arms = vec![];
+ for variant in list.variants() {
+ let name = variant.name().unwrap();
+
+ // => Self::<Variant>
+ let first = make::ext::ident_path("Self");
+ let second = make::ext::ident_path(&format!("{}", name));
+ let pat = make::path_pat(make::path_concat(first, second));
+
+ // => write!(f, "<Variant>")
+ 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 target = make::expr_path(make::ext::ident_path("write"));
+ let expr = make::expr_macro_call(target, args);
+
+ // => Self::<Variant> => write!(f, "<Variant>"),
+ arms.push(make::match_arm(Some(pat.into()), None, expr.into()));
+ }
+
+ // => match self { ... }
+ let f_path = make::expr_path(make::ext::ident_path("self"));
+ let list = make::match_arm_list(arms);
+ let expr = make::expr_match(f_path, list);
+
+ let body = make::block_expr(None, Some(expr)).indent(ast::edit::IndentLevel(1));
+ ted::replace(func.body().unwrap().syntax(), body.clone_for_update().syntax());
+ }
+ }
ast::Adt::Struct(strukt) => match strukt.field_list() {
Some(ast::FieldList::RecordFieldList(field_list)) => {
let name = format!("\"{}\"", annotated_name);
@@ -383,6 +413,52 @@ impl fmt::Debug for Foo {
f.debug_struct("Foo").finish()
}
}
+"#,
+ )
+ }
+ #[test]
+ fn add_custom_impl_debug_enum() {
+ check_assist(
+ replace_derive_with_manual_impl,
+ r#"
+mod fmt {
+ pub struct Error;
+ pub type Result = Result<(), Error>;
+ pub struct Formatter<'a>;
+ pub trait Debug {
+ fn fmt(&self, f: &mut Formatter<'_>) -> Result;
+ }
+}
+
+#[derive(Debu$0g)]
+enum Foo {
+ Bar,
+ Baz,
+}
+"#,
+ r#"
+mod fmt {
+ pub struct Error;
+ pub type Result = Result<(), Error>;
+ pub struct Formatter<'a>;
+ pub trait Debug {
+ fn fmt(&self, f: &mut Formatter<'_>) -> Result;
+ }
+}
+
+enum Foo {
+ Bar,
+ Baz,
+}
+
+impl fmt::Debug for Foo {
+ $0fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ match self {
+ Self::Bar => write!(f, "Bar"),
+ Self::Baz => write!(f, "Baz"),
+ }
+ }
+}
"#,
)
}
diff --git a/crates/syntax/src/ast/make.rs b/crates/syntax/src/ast/make.rs
index 71254f08543..87faac0aa32 100644
--- a/crates/syntax/src/ast/make.rs
+++ b/crates/syntax/src/ast/make.rs
@@ -311,6 +311,9 @@ pub fn expr_method_call(
) -> ast::Expr {
expr_from_text(&format!("{}.{}{}", receiver, method, arg_list))
}
+pub fn expr_macro_call(f: ast::Expr, arg_list: ast::ArgList) -> ast::Expr {
+ expr_from_text(&format!("{}!{}", f, arg_list))
+}
pub fn expr_ref(expr: ast::Expr, exclusive: bool) -> ast::Expr {
expr_from_text(&if exclusive { format!("&mut {}", expr) } else { format!("&{}", expr) })
}