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//! FIXME: write short doc here
use hir::db::HirDatabase;
use ra_syntax::{
ast::{self, edit, make, AstNode, NameOwner, TypeBoundsOwner},
SyntaxElement,
SyntaxKind::*,
};
use crate::{Assist, AssistCtx, AssistId};
pub(crate) fn move_bounds_to_where_clause(mut ctx: AssistCtx<impl HirDatabase>) -> Option<Assist> {
let type_param_list = ctx.node_at_offset::<ast::TypeParamList>()?;
let mut type_params = type_param_list.type_params();
if type_params.all(|p| p.type_bound_list().is_none()) {
return None;
}
let parent = type_param_list.syntax().parent()?;
if parent.children_with_tokens().any(|it| it.kind() == WHERE_CLAUSE) {
return None;
}
let anchor: SyntaxElement = match parent.kind() {
FN_DEF => ast::FnDef::cast(parent)?.body()?.syntax().clone().into(),
TRAIT_DEF => ast::TraitDef::cast(parent)?.item_list()?.syntax().clone().into(),
IMPL_BLOCK => ast::ImplBlock::cast(parent)?.item_list()?.syntax().clone().into(),
ENUM_DEF => ast::EnumDef::cast(parent)?.variant_list()?.syntax().clone().into(),
STRUCT_DEF => parent
.children_with_tokens()
.find(|it| it.kind() == RECORD_FIELD_DEF_LIST || it.kind() == SEMI)?,
_ => return None,
};
ctx.add_action(
AssistId("move_bounds_to_where_clause"),
"move_bounds_to_where_clause",
|edit| {
let new_params = type_param_list
.type_params()
.filter(|it| it.type_bound_list().is_some())
.map(|type_param| {
let without_bounds = type_param.remove_bounds();
(type_param, without_bounds)
});
let new_type_param_list = edit::replace_descendants(&type_param_list, new_params);
edit.replace_ast(type_param_list.clone(), new_type_param_list);
let where_clause = {
let predicates = type_param_list.type_params().filter_map(build_predicate);
make::where_clause(predicates)
};
let to_insert = match anchor.prev_sibling_or_token() {
Some(ref elem) if elem.kind() == WHITESPACE => {
format!("{} ", where_clause.syntax())
}
_ => format!(" {}", where_clause.syntax()),
};
edit.insert(anchor.text_range().start(), to_insert);
edit.target(type_param_list.syntax().text_range());
},
);
ctx.build()
}
fn build_predicate(param: ast::TypeParam) -> Option<ast::WherePred> {
let path = make::path_from_name_ref(make::name_ref(¶m.name()?.syntax().to_string()));
let predicate = make::where_pred(path, param.type_bound_list()?.bounds());
Some(predicate)
}
#[cfg(test)]
mod tests {
use super::*;
use crate::helpers::check_assist;
#[test]
fn move_bounds_to_where_clause_fn() {
check_assist(
move_bounds_to_where_clause,
r#"
fn foo<T: u32, <|>F: FnOnce(T) -> T>() {}
"#,
r#"
fn foo<T, <|>F>() where T: u32, F: FnOnce(T) -> T {}
"#,
);
}
#[test]
fn move_bounds_to_where_clause_impl() {
check_assist(
move_bounds_to_where_clause,
r#"
impl<U: u32, <|>T> A<U, T> {}
"#,
r#"
impl<U, <|>T> A<U, T> where U: u32 {}
"#,
);
}
#[test]
fn move_bounds_to_where_clause_struct() {
check_assist(
move_bounds_to_where_clause,
r#"
struct A<<|>T: Iterator<Item = u32>> {}
"#,
r#"
struct A<<|>T> where T: Iterator<Item = u32> {}
"#,
);
}
#[test]
fn move_bounds_to_where_clause_tuple_struct() {
check_assist(
move_bounds_to_where_clause,
r#"
struct Pair<<|>T: u32>(T, T);
"#,
r#"
struct Pair<<|>T>(T, T) where T: u32;
"#,
);
}
}
|
