rust/crates/ide_assists/src/handlers/move_guard.rs

391 lines
8.2 KiB
Rust

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()?;
if ctx.offset() > guard.syntax().text_range().end() {
cov_mark::hit!(move_guard_unapplicable_in_arm_body);
return None;
}
let space_before_guard = guard.syntax().prev_sibling_or_token();
// FIXME: support `if let` guards too
if guard.let_token().is_some() {
return None;
}
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.is_pattern_cond() {
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_range() {
cov_mark::check!(move_guard_unapplicable_in_arm_body);
check_assist_not_applicable(
move_guard_to_arm_body,
r#"
fn main() {
match 92 {
x if x > 10 => $0false,
_ => true
}
}
"#,
);
}
#[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
}
}
"#,
)
}
}