use syntax::{ ast::{edit::AstNodeEdit, make, AstNode, BlockExpr, Expr, IfExpr, MatchArm}, SyntaxKind::WHITESPACE, }; use crate::{AssistContext, AssistId, AssistKind, Assists}; // Assist: move_guard_to_arm_body // // Moves match guard into match arm body. // // ``` // enum Action { Move { distance: u32 }, Stop } // // fn handle(action: Action) { // match action { // Action::Move { distance } $0if distance > 10 => foo(), // _ => (), // } // } // ``` // -> // ``` // enum Action { Move { distance: u32 }, Stop } // // fn handle(action: Action) { // match action { // Action::Move { distance } => if distance > 10 { // foo() // }, // _ => (), // } // } // ``` pub(crate) fn move_guard_to_arm_body(acc: &mut Assists, ctx: &AssistContext) -> Option<()> { let match_arm = ctx.find_node_at_offset::<MatchArm>()?; let guard = match_arm.guard()?; let space_before_guard = guard.syntax().prev_sibling_or_token(); let guard_condition = guard.expr()?; let arm_expr = match_arm.expr()?; let if_expr = make::expr_if( make::condition(guard_condition, None), make::block_expr(None, Some(arm_expr.clone())), None, ) .indent(arm_expr.indent_level()); let target = guard.syntax().text_range(); acc.add( AssistId("move_guard_to_arm_body", AssistKind::RefactorRewrite), "Move guard to arm body", target, |edit| { match space_before_guard { Some(element) if element.kind() == WHITESPACE => { edit.delete(element.text_range()); } _ => (), }; edit.delete(guard.syntax().text_range()); edit.replace_ast(arm_expr, if_expr); }, ) } // Assist: move_arm_cond_to_match_guard // // Moves if expression from match arm body into a guard. // // ``` // enum Action { Move { distance: u32 }, Stop } // // fn handle(action: Action) { // match action { // Action::Move { distance } => $0if distance > 10 { foo() }, // _ => (), // } // } // ``` // -> // ``` // enum Action { Move { distance: u32 }, Stop } // // fn handle(action: Action) { // match action { // Action::Move { distance } if distance > 10 => foo(), // _ => (), // } // } // ``` pub(crate) fn move_arm_cond_to_match_guard(acc: &mut Assists, ctx: &AssistContext) -> Option<()> { let match_arm: MatchArm = ctx.find_node_at_offset::<MatchArm>()?; let match_pat = match_arm.pat()?; let arm_body = match_arm.expr()?; let mut replace_node = None; let if_expr: IfExpr = IfExpr::cast(arm_body.syntax().clone()).or_else(|| { let block_expr = BlockExpr::cast(arm_body.syntax().clone())?; if let Expr::IfExpr(e) = block_expr.tail_expr()? { replace_node = Some(block_expr.syntax().clone()); Some(e) } else { None } })?; let replace_node = replace_node.unwrap_or_else(|| if_expr.syntax().clone()); let cond = if_expr.condition()?; let then_block = if_expr.then_branch()?; // Not support if with else branch if if_expr.else_branch().is_some() { return None; } // Not support moving if let to arm guard if cond.pat().is_some() { return None; } let buf = format!(" if {}", cond.syntax().text()); acc.add( AssistId("move_arm_cond_to_match_guard", AssistKind::RefactorRewrite), "Move condition to match guard", replace_node.text_range(), |edit| { let then_only_expr = then_block.statements().next().is_none(); match &then_block.tail_expr() { Some(then_expr) if then_only_expr => { edit.replace(replace_node.text_range(), then_expr.syntax().text()) } _ if replace_node != *if_expr.syntax() => { // Dedent because if_expr is in a BlockExpr let replace_with = then_block.dedent(1.into()).syntax().text(); edit.replace(replace_node.text_range(), replace_with) } _ => edit.replace(replace_node.text_range(), then_block.syntax().text()), } edit.insert(match_pat.syntax().text_range().end(), buf); }, ) } #[cfg(test)] mod tests { use super::*; use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target}; #[test] fn move_guard_to_arm_body_target() { check_assist_target( move_guard_to_arm_body, r#" fn main() { match 92 { x $0if x > 10 => false, _ => true } } "#, r#"if x > 10"#, ); } #[test] fn move_guard_to_arm_body_works() { check_assist( move_guard_to_arm_body, r#" fn main() { match 92 { x $0if x > 10 => false, _ => true } } "#, r#" fn main() { match 92 { x => if x > 10 { false }, _ => true } } "#, ); } #[test] fn move_guard_to_arm_body_works_complex_match() { check_assist( move_guard_to_arm_body, r#" fn main() { match 92 { $0x @ 4 | x @ 5 if x > 5 => true, _ => false } } "#, r#" fn main() { match 92 { x @ 4 | x @ 5 => if x > 5 { true }, _ => false } } "#, ); } #[test] fn move_arm_cond_to_match_guard_works() { check_assist( move_arm_cond_to_match_guard, r#" fn main() { match 92 { x => if x > 10 { $0false }, _ => true } } "#, r#" fn main() { match 92 { x if x > 10 => false, _ => true } } "#, ); } #[test] fn move_arm_cond_in_block_to_match_guard_works() { check_assist( move_arm_cond_to_match_guard, r#" fn main() { match 92 { x => { $0if x > 10 { false } }, _ => true } } "#, r#" fn main() { match 92 { x if x > 10 => false, _ => true } } "#, ); } #[test] fn move_arm_cond_to_match_guard_if_let_not_works() { check_assist_not_applicable( move_arm_cond_to_match_guard, r#" fn main() { match 92 { x => if let 62 = x { $0false }, _ => true } } "#, ); } #[test] fn move_arm_cond_to_match_guard_if_empty_body_works() { check_assist( move_arm_cond_to_match_guard, r#" fn main() { match 92 { x => if x > 10 { $0 }, _ => true } } "#, r#" fn main() { match 92 { x if x > 10 => { }, _ => true } } "#, ); } #[test] fn move_arm_cond_to_match_guard_if_multiline_body_works() { check_assist( move_arm_cond_to_match_guard, r#" fn main() { match 92 { x => if x > 10 { 92;$0 false }, _ => true } } "#, r#" fn main() { match 92 { x if x > 10 => { 92; false }, _ => true } } "#, ); } #[test] fn move_arm_cond_in_block_to_match_guard_if_multiline_body_works() { check_assist( move_arm_cond_to_match_guard, r#" fn main() { match 92 { x => { if x > 10 { 92;$0 false } } _ => true } } "#, r#" fn main() { match 92 { x if x > 10 => { 92; false } _ => true } } "#, ) } }