rust/crates/ra_assists/src/utils.rs

102 lines
3.2 KiB
Rust

//! Assorted functions shared by several assists.
use ra_syntax::{
ast::{self, make, NameOwner},
AstNode, T,
};
use hir::db::HirDatabase;
use rustc_hash::FxHashSet;
/// Generate a collection of associated items that are missing from a
/// `impl Trait for` block.
pub fn get_missing_impl_items(
db: &impl HirDatabase,
analyzer: &hir::SourceAnalyzer,
impl_block: &ast::ImplBlock,
) -> 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_block.item_list() {
for item in item_list.impl_items() {
match item {
ast::ImplItem::FnDef(f) => {
if let Some(n) = f.name() {
impl_fns_consts.insert(n.syntax().to_string());
}
}
ast::ImplItem::TypeAliasDef(t) => {
if let Some(n) = t.name() {
impl_type.insert(n.syntax().to_string());
}
}
ast::ImplItem::ConstDef(c) => {
if let Some(n) = c.name() {
impl_fns_consts.insert(n.syntax().to_string());
}
}
}
}
}
resolve_target_trait(db, analyzer, impl_block).map_or(vec![], |target_trait| {
target_trait
.items(db)
.iter()
.filter(|i| match i {
hir::AssocItem::Function(f) => !impl_fns_consts.contains(&f.name(db).to_string()),
hir::AssocItem::TypeAlias(t) => !impl_type.contains(&t.name(db).to_string()),
hir::AssocItem::Const(c) => {
c.name(db).map(|n| !impl_fns_consts.contains(&n.to_string())).unwrap_or_default()
}
})
.map(|i| i.clone())
.collect()
})
}
fn resolve_target_trait(
db: &impl HirDatabase,
analyzer: &hir::SourceAnalyzer,
impl_block: &ast::ImplBlock,
) -> Option<hir::Trait> {
let ast_path = impl_block
.target_trait()
.map(|it| it.syntax().clone())
.and_then(ast::PathType::cast)?
.path()?;
match analyzer.resolve_path(db, &ast_path) {
Some(hir::PathResolution::Def(hir::ModuleDef::Trait(def))) => Some(def),
_ => None,
}
}
pub(crate) fn invert_boolean_expression(expr: ast::Expr) -> ast::Expr {
if let Some(expr) = invert_special_case(&expr) {
return expr;
}
make::expr_prefix(T![!], expr)
}
fn invert_special_case(expr: &ast::Expr) -> Option<ast::Expr> {
match expr {
ast::Expr::BinExpr(bin) => match bin.op_kind()? {
ast::BinOp::NegatedEqualityTest => bin.replace_op(T![==]).map(|it| it.into()),
ast::BinOp::EqualityTest => bin.replace_op(T![!=]).map(|it| it.into()),
_ => None,
},
ast::Expr::PrefixExpr(pe) if pe.op_kind()? == ast::PrefixOp::Not => pe.expr(),
// FIXME:
// ast::Expr::Literal(true | false )
_ => None,
}
}