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gen PartialEq for structs

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This commit is contained in:
Yoshua Wuyts 2021-08-10 19:49:06 +02:00
parent 3cad2c4feb
commit f8a64c044a
1 changed files with 60 additions and 0 deletions
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60
crates/ide_assists/src/utils/gen_trait_fn_body.rs
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@ -20,6 +20,7 @@ pub(crate) fn gen_trait_fn_body(
"Debug" => gen_debug_impl(adt, func),
"Default" => gen_default_impl(adt, func),
"Hash" => gen_hash_impl(adt, func),
"PartialEq" => gen_partial_eq(adt, func),
_ => None,
}
}
@ -326,3 +327,62 @@ fn gen_hash_impl(adt: &ast::Adt, func: &ast::Fn) -> Option<()> {
ted::replace(func.body()?.syntax(), body.clone_for_update().syntax());
Some(())
}
/// Generate a `PartialEq` impl based on the fields and members of the target type.
fn gen_partial_eq(adt: &ast::Adt, func: &ast::Fn) -> Option<()> {
// FIXME: return `None` if the trait carries a generic type; we can only
// generate this code `Self` for the time being.
let body = match adt {
// `Hash` cannot be derived for unions, so no default impl can be provided.
ast::Adt::Union(_) => return None,
// FIXME: generate trait variants
ast::Adt::Enum(_) => todo!(),
ast::Adt::Struct(strukt) => match strukt.field_list() {
// => self.<field>.hash(state);
Some(ast::FieldList::RecordFieldList(field_list)) => {
let mut expr = None;
for field in field_list.fields() {
let lhs = make::expr_path(make::ext::ident_path("self"));
let lhs = make::expr_field(lhs, &field.name()?.to_string());
let rhs = make::expr_path(make::ext::ident_path("other"));
let rhs = make::expr_field(rhs, &field.name()?.to_string());
let cmp = make::expr_op(ast::BinOp::EqualityTest, lhs, rhs);
expr = match expr {
Some(expr) => Some(make::expr_op(ast::BinOp::BooleanAnd, expr, cmp)),
None => Some(cmp),
};
}
make::block_expr(None, expr).indent(ast::edit::IndentLevel(1))
}
// => self.<field_index>.hash(state);
Some(ast::FieldList::TupleFieldList(field_list)) => {
let mut expr = None;
for (i, _) in field_list.fields().enumerate() {
let idx = format!("{}", i);
let lhs = make::expr_path(make::ext::ident_path("self"));
let lhs = make::expr_field(lhs, &idx);
let rhs = make::expr_path(make::ext::ident_path("other"));
let rhs = make::expr_field(rhs, &idx);
let cmp = make::expr_op(ast::BinOp::EqualityTest, lhs, rhs);
expr = match expr {
Some(expr) => Some(make::expr_op(ast::BinOp::BooleanAnd, expr, cmp)),
None => Some(cmp),
};
}
make::block_expr(None, expr).indent(ast::edit::IndentLevel(1))
}
// No fields in the body means there's nothing to hash.
None => {
let expr = make::expr_literal("true").into();
make::block_expr(None, Some(expr)).indent(ast::edit::IndentLevel(1))
}
},
};
ted::replace(func.body()?.syntax(), body.clone_for_update().syntax());
Some(())
}