use hir::db::HirDatabase; use ra_syntax::{ ast::{self, AstNode, NameOwner, TypeBoundsOwner}, SyntaxElement, SyntaxKind::*, TextRange, }; use crate::{ast_editor::AstBuilder, Assist, AssistCtx, AssistId}; pub(crate) fn move_bounds_to_where_clause(mut ctx: AssistCtx) -> Option { let type_param_list = ctx.node_at_offset::()?; 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().find(|it| it.kind() == WHERE_CLAUSE).is_some() { 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 type_params = type_param_list.type_params().collect::>(); for param in &type_params { if let Some(bounds) = param.type_bound_list() { let colon = param .syntax() .children_with_tokens() .find(|it| it.kind() == COLON) .unwrap(); let start = colon.text_range().start(); let end = bounds.syntax().text_range().end(); edit.delete(TextRange::from_to(start, end)); } } let predicates = type_params.iter().filter_map(build_predicate); let where_clause = AstBuilder::::from_predicates(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 { let path = AstBuilder::::from_name(param.name()?); let predicate = AstBuilder::::from_pieces(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 fooF: FnOnce(T) -> T>() {} "#, r#" fn fooF>() where T: u32, F: FnOnce(T) -> T {} "#, ); } #[test] fn move_bounds_to_where_clause_impl() { check_assist( move_bounds_to_where_clause, r#" implT> A {} "#, r#" implT> A where U: u32 {} "#, ); } #[test] fn move_bounds_to_where_clause_struct() { check_assist( move_bounds_to_where_clause, r#" struct A<<|>T: Iterator> {} "#, r#" struct A<<|>T> where T: Iterator {} "#, ); } #[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; "#, ); } }