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|
//! Functionality for obtaining data related to traits from the DB.
use crate::RootDatabase;
use hir::Semantics;
use rustc_hash::FxHashSet;
use syntax::{
ast::{self, NameOwner},
AstNode,
};
/// Given the `impl` block, attempts to find the trait this `impl` corresponds to.
pub fn resolve_target_trait(
sema: &Semantics<RootDatabase>,
impl_def: &ast::Impl,
) -> Option<hir::Trait> {
let ast_path =
impl_def.trait_().map(|it| it.syntax().clone()).and_then(ast::PathType::cast)?.path()?;
match sema.resolve_path(&ast_path) {
Some(hir::PathResolution::Def(hir::ModuleDef::Trait(def))) => Some(def),
_ => None,
}
}
/// Given the `impl` block, returns the list of associated items (e.g. functions or types) that are
/// missing in this `impl` block.
pub fn get_missing_assoc_items(
sema: &Semantics<RootDatabase>,
impl_def: &ast::Impl,
) -> Vec<hir::AssocItem> {
// Names must be unique between constants and functions. However, type aliases
// may share the same name as a function or constant.
let mut impl_fns_consts = FxHashSet::default();
let mut impl_type = FxHashSet::default();
if let Some(item_list) = impl_def.assoc_item_list() {
for item in item_list.assoc_items() {
match item {
ast::AssocItem::Fn(f) => {
if let Some(n) = f.name() {
impl_fns_consts.insert(n.syntax().to_string());
}
}
ast::AssocItem::TypeAlias(t) => {
if let Some(n) = t.name() {
impl_type.insert(n.syntax().to_string());
}
}
ast::AssocItem::Const(c) => {
if let Some(n) = c.name() {
impl_fns_consts.insert(n.syntax().to_string());
}
}
ast::AssocItem::MacroCall(_) => (),
}
}
}
resolve_target_trait(sema, impl_def).map_or(vec![], |target_trait| {
target_trait
.items(sema.db)
.iter()
.filter(|i| match i {
hir::AssocItem::Function(f) => {
!impl_fns_consts.contains(&f.name(sema.db).to_string())
}
hir::AssocItem::TypeAlias(t) => !impl_type.contains(&t.name(sema.db).to_string()),
hir::AssocItem::Const(c) => c
.name(sema.db)
.map(|n| !impl_fns_consts.contains(&n.to_string()))
.unwrap_or_default(),
})
.cloned()
.collect()
})
}
#[cfg(test)]
mod tests {
use crate::RootDatabase;
use base_db::{fixture::ChangeFixture, FilePosition};
use expect_test::{expect, Expect};
use hir::Semantics;
use syntax::ast::{self, AstNode};
use test_utils::RangeOrOffset;
/// Creates analysis from a multi-file fixture, returns positions marked with <|>.
pub(crate) fn position(ra_fixture: &str) -> (RootDatabase, FilePosition) {
let change_fixture = ChangeFixture::parse(ra_fixture);
let mut database = RootDatabase::default();
database.apply_change(change_fixture.change);
let (file_id, range_or_offset) =
change_fixture.file_position.expect("expected a marker (<|>)");
let offset = match range_or_offset {
RangeOrOffset::Range(_) => panic!(),
RangeOrOffset::Offset(it) => it,
};
(database, FilePosition { file_id, offset })
}
fn check_trait(ra_fixture: &str, expect: Expect) {
let (db, position) = position(ra_fixture);
let sema = Semantics::new(&db);
let file = sema.parse(position.file_id);
let impl_block: ast::Impl =
sema.find_node_at_offset_with_descend(file.syntax(), position.offset).unwrap();
let trait_ = crate::traits::resolve_target_trait(&sema, &impl_block);
let actual = match trait_ {
Some(trait_) => trait_.name(&db).to_string(),
None => String::new(),
};
expect.assert_eq(&actual);
}
fn check_missing_assoc(ra_fixture: &str, expect: Expect) {
let (db, position) = position(ra_fixture);
let sema = Semantics::new(&db);
let file = sema.parse(position.file_id);
let impl_block: ast::Impl =
sema.find_node_at_offset_with_descend(file.syntax(), position.offset).unwrap();
let items = crate::traits::get_missing_assoc_items(&sema, &impl_block);
let actual = items
.into_iter()
.map(|item| item.name(&db).unwrap().to_string())
.collect::<Vec<_>>()
.join("\n");
expect.assert_eq(&actual);
}
#[test]
fn resolve_trait() {
check_trait(
r#"
pub trait Foo {
fn bar();
}
impl Foo for u8 {
<|>
}
"#,
expect![["Foo"]],
);
check_trait(
r#"
pub trait Foo {
fn bar();
}
impl Foo for u8 {
fn bar() {
fn baz() {
<|>
}
baz();
}
}
"#,
expect![["Foo"]],
);
check_trait(
r#"
pub trait Foo {
fn bar();
}
pub struct Bar;
impl Bar {
<|>
}
"#,
expect![[""]],
);
}
#[test]
fn missing_assoc_items() {
check_missing_assoc(
r#"
pub trait Foo {
const FOO: u8;
fn bar();
}
impl Foo for u8 {
<|>
}"#,
expect![[r#"
FOO
bar"#]],
);
check_missing_assoc(
r#"
pub trait Foo {
const FOO: u8;
fn bar();
}
impl Foo for u8 {
const FOO: u8 = 10;
<|>
}"#,
expect![[r#"
bar"#]],
);
check_missing_assoc(
r#"
pub trait Foo {
const FOO: u8;
fn bar();
}
impl Foo for u8 {
const FOO: u8 = 10;
fn bar() {<|>}
}"#,
expect![[r#""#]],
);
check_missing_assoc(
r#"
pub struct Foo;
impl Foo {
fn bar() {<|>}
}"#,
expect![[r#""#]],
);
}
}
|
