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|
use ra_ide_db::RootDatabase;
use ra_syntax::ast::{self, AstNode, NameOwner};
use test_utils::mark;
use crate::{utils::FamousDefs, AssistContext, AssistId, AssistKind, Assists};
// Assist: generate_from_impl_for_enum
//
// Adds a From impl for an enum variant with one tuple field.
//
// ```
// enum A { <|>One(u32) }
// ```
// ->
// ```
// enum A { One(u32) }
//
// impl From<u32> for A {
// fn from(v: u32) -> Self {
// A::One(v)
// }
// }
// ```
pub(crate) fn generate_from_impl_for_enum(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
let variant = ctx.find_node_at_offset::<ast::EnumVariant>()?;
let variant_name = variant.name()?;
let enum_name = variant.parent_enum().name()?;
let field_list = match variant.kind() {
ast::StructKind::Tuple(field_list) => field_list,
_ => return None,
};
if field_list.fields().count() != 1 {
return None;
}
let field_type = field_list.fields().next()?.type_ref()?;
let path = match field_type {
ast::TypeRef::PathType(it) => it,
_ => return None,
};
if existing_from_impl(&ctx.sema, &variant).is_some() {
mark::hit!(test_add_from_impl_already_exists);
return None;
}
let target = variant.syntax().text_range();
acc.add(
AssistId("generate_from_impl_for_enum", AssistKind::Refactor),
"Generate `From` impl for this enum variant",
target,
|edit| {
let start_offset = variant.parent_enum().syntax().text_range().end();
let buf = format!(
r#"
impl From<{0}> for {1} {{
fn from(v: {0}) -> Self {{
{1}::{2}(v)
}}
}}"#,
path.syntax(),
enum_name,
variant_name
);
edit.insert(start_offset, buf);
},
)
}
fn existing_from_impl(
sema: &'_ hir::Semantics<'_, RootDatabase>,
variant: &ast::EnumVariant,
) -> Option<()> {
let variant = sema.to_def(variant)?;
let enum_ = variant.parent_enum(sema.db);
let krate = enum_.module(sema.db).krate();
let from_trait = FamousDefs(sema, krate).core_convert_From()?;
let enum_type = enum_.ty(sema.db);
let wrapped_type = variant.fields(sema.db).get(0)?.signature_ty(sema.db);
if enum_type.impls_trait(sema.db, from_trait, &[wrapped_type]) {
Some(())
} else {
None
}
}
#[cfg(test)]
mod tests {
use test_utils::mark;
use crate::tests::{check_assist, check_assist_not_applicable};
use super::*;
#[test]
fn test_generate_from_impl_for_enum() {
check_assist(
generate_from_impl_for_enum,
"enum A { <|>One(u32) }",
r#"enum A { One(u32) }
impl From<u32> for A {
fn from(v: u32) -> Self {
A::One(v)
}
}"#,
);
}
#[test]
fn test_generate_from_impl_for_enum_complicated_path() {
check_assist(
generate_from_impl_for_enum,
r#"enum A { <|>One(foo::bar::baz::Boo) }"#,
r#"enum A { One(foo::bar::baz::Boo) }
impl From<foo::bar::baz::Boo> for A {
fn from(v: foo::bar::baz::Boo) -> Self {
A::One(v)
}
}"#,
);
}
fn check_not_applicable(ra_fixture: &str) {
let fixture =
format!("//- /main.rs crate:main deps:core\n{}\n{}", ra_fixture, FamousDefs::FIXTURE);
check_assist_not_applicable(generate_from_impl_for_enum, &fixture)
}
#[test]
fn test_add_from_impl_no_element() {
check_not_applicable("enum A { <|>One }");
}
#[test]
fn test_add_from_impl_more_than_one_element_in_tuple() {
check_not_applicable("enum A { <|>One(u32, String) }");
}
#[test]
fn test_add_from_impl_struct_variant() {
check_not_applicable("enum A { <|>One { x: u32 } }");
}
#[test]
fn test_add_from_impl_already_exists() {
mark::check!(test_add_from_impl_already_exists);
check_not_applicable(
r#"
enum A { <|>One(u32), }
impl From<u32> for A {
fn from(v: u32) -> Self {
A::One(v)
}
}
"#,
);
}
#[test]
fn test_add_from_impl_different_variant_impl_exists() {
check_assist(
generate_from_impl_for_enum,
r#"enum A { <|>One(u32), Two(String), }
impl From<String> for A {
fn from(v: String) -> Self {
A::Two(v)
}
}
pub trait From<T> {
fn from(T) -> Self;
}"#,
r#"enum A { One(u32), Two(String), }
impl From<u32> for A {
fn from(v: u32) -> Self {
A::One(v)
}
}
impl From<String> for A {
fn from(v: String) -> Self {
A::Two(v)
}
}
pub trait From<T> {
fn from(T) -> Self;
}"#,
);
}
}
|
