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|
use ra_syntax::{
ast::{self, AstNode, NameOwner},
TextSize,
};
use stdx::format_to;
use crate::{Assist, AssistCtx, AssistId};
use ra_ide_db::RootDatabase;
// Assist add_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 add_from_impl_for_enum(ctx: AssistCtx) -> Option<Assist> {
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(p) => p,
_ => return None,
};
if already_has_from_impl(ctx.sema, &variant) {
return None;
}
ctx.add_assist(
AssistId("add_from_impl_for_enum"),
"Add From impl for this enum variant",
|edit| {
let start_offset = variant.parent_enum().syntax().text_range().end();
let mut buf = String::new();
format_to!(
buf,
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);
edit.set_cursor(start_offset + TextSize::of("\n\n"));
},
)
}
fn already_has_from_impl(
sema: &'_ hir::Semantics<'_, RootDatabase>,
variant: &ast::EnumVariant,
) -> bool {
let scope = sema.scope(&variant.syntax());
let from_path = ast::make::path_from_text("From");
let from_hir_path = match hir::Path::from_ast(from_path) {
Some(p) => p,
None => return false,
};
let from_trait = match scope.resolve_hir_path(&from_hir_path) {
Some(hir::PathResolution::Def(hir::ModuleDef::Trait(t))) => t,
_ => return false,
};
let e: hir::Enum = match sema.to_def(&variant.parent_enum()) {
Some(e) => e,
None => return false,
};
let e_ty = e.ty(sema.db);
let hir_enum_var: hir::EnumVariant = match sema.to_def(variant) {
Some(ev) => ev,
None => return false,
};
let var_ty = hir_enum_var.fields(sema.db)[0].signature_ty(sema.db);
e_ty.impls_trait(sema.db, from_trait, &[var_ty])
}
#[cfg(test)]
mod tests {
use super::*;
use crate::helpers::{check_assist, check_assist_not_applicable};
#[test]
fn test_add_from_impl_for_enum() {
check_assist(
add_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_add_from_impl_for_enum_complicated_path() {
check_assist(
add_from_impl_for_enum,
"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)
}
}"#,
);
}
#[test]
fn test_add_from_impl_no_element() {
check_assist_not_applicable(add_from_impl_for_enum, "enum A { <|>One }");
}
#[test]
fn test_add_from_impl_more_than_one_element_in_tuple() {
check_assist_not_applicable(add_from_impl_for_enum, "enum A { <|>One(u32, String) }");
}
#[test]
fn test_add_from_impl_struct_variant() {
check_assist_not_applicable(add_from_impl_for_enum, "enum A { <|>One { x: u32 } }");
}
#[test]
fn test_add_from_impl_already_exists() {
check_assist_not_applicable(
add_from_impl_for_enum,
r#"enum A { <|>One(u32), }
impl From<u32> for A {
fn from(v: u32) -> Self {
A::One(v)
}
}
pub trait From<T> {
fn from(T) -> Self;
}"#,
);
}
#[test]
fn test_add_from_impl_different_variant_impl_exists() {
check_assist(
add_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;
}"#,
);
}
}
|
