rust/crates/ide-assists/src/handlers/move_guard.rs
2022-07-20 15:02:08 +02:00

995 lines
20 KiB
Rust

use syntax::{
ast::{edit::AstNodeEdit, make, AstNode, BlockExpr, ElseBranch, Expr, IfExpr, MatchArm, Pat},
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();
let guard_condition = guard.condition()?;
let arm_expr = match_arm.expr()?;
let if_expr =
make::expr_if(guard_condition, 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
}
})?;
if ctx.offset() > if_expr.then_branch()?.syntax().text_range().start() {
return None;
}
let replace_node = replace_node.unwrap_or_else(|| if_expr.syntax().clone());
let needs_dedent = replace_node != *if_expr.syntax();
let (conds_blocks, tail) = parse_if_chain(if_expr)?;
acc.add(
AssistId("move_arm_cond_to_match_guard", AssistKind::RefactorRewrite),
"Move condition to match guard",
replace_node.text_range(),
|edit| {
edit.delete(match_arm.syntax().text_range());
// Dedent if if_expr is in a BlockExpr
let dedent = if needs_dedent {
cov_mark::hit!(move_guard_ifelse_in_block);
1
} else {
cov_mark::hit!(move_guard_ifelse_else_block);
0
};
let then_arm_end = match_arm.syntax().text_range().end();
let indent_level = match_arm.indent_level();
let spaces = " ".repeat(indent_level.0 as _);
let mut first = true;
for (cond, block) in conds_blocks {
if !first {
edit.insert(then_arm_end, format!("\n{}", spaces));
} else {
first = false;
}
let guard = format!("{} if {} => ", match_pat, cond.syntax().text());
edit.insert(then_arm_end, guard);
let only_expr = block.statements().next().is_none();
match &block.tail_expr() {
Some(then_expr) if only_expr => {
edit.insert(then_arm_end, then_expr.syntax().text());
edit.insert(then_arm_end, ",");
}
_ => {
let to_insert = block.dedent(dedent.into()).syntax().text();
edit.insert(then_arm_end, to_insert)
}
}
}
if let Some(e) = tail {
cov_mark::hit!(move_guard_ifelse_else_tail);
let guard = format!("\n{}{} => ", spaces, match_pat);
edit.insert(then_arm_end, guard);
let only_expr = e.statements().next().is_none();
match &e.tail_expr() {
Some(expr) if only_expr => {
cov_mark::hit!(move_guard_ifelse_expr_only);
edit.insert(then_arm_end, expr.syntax().text());
edit.insert(then_arm_end, ",");
}
_ => {
let to_insert = e.dedent(dedent.into()).syntax().text();
edit.insert(then_arm_end, to_insert)
}
}
} else {
// There's no else branch. Add a pattern without guard, unless the following match
// arm is `_ => ...`
cov_mark::hit!(move_guard_ifelse_notail);
match match_arm.syntax().next_sibling().and_then(MatchArm::cast) {
Some(next_arm)
if matches!(next_arm.pat(), Some(Pat::WildcardPat(_)))
&& next_arm.guard().is_none() =>
{
cov_mark::hit!(move_guard_ifelse_has_wildcard);
}
_ => edit.insert(then_arm_end, format!("\n{}{} => {{}}", spaces, match_pat)),
}
}
},
)
}
// Parses an if-else-if chain to get the conditions and the then branches until we encounter an else
// branch or the end.
fn parse_if_chain(if_expr: IfExpr) -> Option<(Vec<(Expr, BlockExpr)>, Option<BlockExpr>)> {
let mut conds_blocks = Vec::new();
let mut curr_if = if_expr;
let tail = loop {
let cond = curr_if.condition()?;
conds_blocks.push((cond, curr_if.then_branch()?));
match curr_if.else_branch() {
Some(ElseBranch::IfExpr(e)) => {
curr_if = e;
}
Some(ElseBranch::Block(b)) => {
break Some(b);
}
None => break None,
}
};
Some((conds_blocks, tail))
}
#[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_let_guard_to_arm_body_works() {
check_assist(
move_guard_to_arm_body,
r#"
fn main() {
match 92 {
x $0if (let 1 = x) => false,
_ => true
}
}
"#,
r#"
fn main() {
match 92 {
x => if (let 1 = x) {
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$0 { false },
_ => true
}
}
"#,
r#"
fn main() {
match 92 {
x if x > 10 => false,
_ => true
}
}
"#,
);
}
#[test]
fn move_arm_cond_in_block_to_match_guard_works() {
cov_mark::check!(move_guard_ifelse_has_wildcard);
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_in_block_to_match_guard_no_wildcard_works() {
cov_mark::check_count!(move_guard_ifelse_has_wildcard, 0);
check_assist(
move_arm_cond_to_match_guard,
r#"
fn main() {
match 92 {
x => {
$0if x > 10 {
false
}
}
}
}
"#,
r#"
fn main() {
match 92 {
x if x > 10 => false,
x => {}
}
}
"#,
);
}
#[test]
fn move_arm_cond_in_block_to_match_guard_wildcard_guard_works() {
cov_mark::check_count!(move_guard_ifelse_has_wildcard, 0);
check_assist(
move_arm_cond_to_match_guard,
r#"
fn main() {
match 92 {
x => {
$0if x > 10 {
false
}
}
_ if x > 10 => true,
}
}
"#,
r#"
fn main() {
match 92 {
x if x > 10 => false,
x => {}
_ if x > 10 => true,
}
}
"#,
);
}
#[test]
fn move_arm_cond_in_block_to_match_guard_add_comma_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_works() {
check_assist(
move_arm_cond_to_match_guard,
r#"
fn main() {
match 92 {
x => if let 62 = x $0&& true { false },
_ => true
}
}
"#,
r#"
fn main() {
match 92 {
x if let 62 = x && true => false,
_ => 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 $0> 10 { },
_ => 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$0 x > 10 {
92;
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 > $010 {
92;
false
}
}
_ => true
}
}
"#,
r#"
fn main() {
match 92 {
x if x > 10 => {
92;
false
}
_ => true
}
}
"#,
)
}
#[test]
fn move_arm_cond_to_match_guard_with_else_works() {
check_assist(
move_arm_cond_to_match_guard,
r#"
fn main() {
match 92 {
x => if x > $010 {
false
} else {
true
}
_ => true,
}
}
"#,
r#"
fn main() {
match 92 {
x if x > 10 => false,
x => true,
_ => true,
}
}
"#,
)
}
#[test]
fn move_arm_cond_to_match_guard_with_else_block_works() {
cov_mark::check!(move_guard_ifelse_expr_only);
check_assist(
move_arm_cond_to_match_guard,
r#"
fn main() {
match 92 {
x => {
if x $0> 10 {
false
} else {
true
}
}
_ => true
}
}
"#,
r#"
fn main() {
match 92 {
x if x > 10 => false,
x => true,
_ => true
}
}
"#,
)
}
#[test]
fn move_arm_cond_to_match_guard_else_if_empty_body_works() {
check_assist(
move_arm_cond_to_match_guard,
r#"
fn main() {
match 92 {
x => if x > $010 { } else { },
_ => true
}
}
"#,
r#"
fn main() {
match 92 {
x if x > 10 => { }
x => { }
_ => true
}
}
"#,
);
}
#[test]
fn move_arm_cond_to_match_guard_with_else_multiline_works() {
check_assist(
move_arm_cond_to_match_guard,
r#"
fn main() {
match 92 {
x => if$0 x > 10 {
92;
false
} else {
true
}
_ => true
}
}
"#,
r#"
fn main() {
match 92 {
x if x > 10 => {
92;
false
}
x => true,
_ => true
}
}
"#,
)
}
#[test]
fn move_arm_cond_to_match_guard_with_else_multiline_else_works() {
cov_mark::check!(move_guard_ifelse_else_block);
check_assist(
move_arm_cond_to_match_guard,
r#"
fn main() {
match 92 {
x => if x $0> 10 {
false
} else {
42;
true
}
_ => true
}
}
"#,
r#"
fn main() {
match 92 {
x if x > 10 => false,
x => {
42;
true
}
_ => true
}
}
"#,
)
}
#[test]
fn move_arm_cond_to_match_guard_with_else_multiline_else_block_works() {
cov_mark::check!(move_guard_ifelse_in_block);
check_assist(
move_arm_cond_to_match_guard,
r#"
fn main() {
match 92 {
x => {
if x > $010 {
false
} else {
42;
true
}
}
_ => true
}
}
"#,
r#"
fn main() {
match 92 {
x if x > 10 => false,
x => {
42;
true
}
_ => true
}
}
"#,
)
}
#[test]
fn move_arm_cond_to_match_guard_with_else_last_arm_works() {
check_assist(
move_arm_cond_to_match_guard,
r#"
fn main() {
match 92 {
3 => true,
x => {
if x > $010 {
false
} else {
92;
true
}
}
}
}
"#,
r#"
fn main() {
match 92 {
3 => true,
x if x > 10 => false,
x => {
92;
true
}
}
}
"#,
)
}
#[test]
fn move_arm_cond_to_match_guard_with_else_comma_works() {
check_assist(
move_arm_cond_to_match_guard,
r#"
fn main() {
match 92 {
3 => true,
x => if x > $010 {
false
} else {
92;
true
},
}
}
"#,
r#"
fn main() {
match 92 {
3 => true,
x if x > 10 => false,
x => {
92;
true
}
}
}
"#,
)
}
#[test]
fn move_arm_cond_to_match_guard_elseif() {
check_assist(
move_arm_cond_to_match_guard,
r#"
fn main() {
match 92 {
3 => true,
x => if x $0> 10 {
false
} else if x > 5 {
true
} else if x > 4 {
false
} else {
true
},
}
}
"#,
r#"
fn main() {
match 92 {
3 => true,
x if x > 10 => false,
x if x > 5 => true,
x if x > 4 => false,
x => true,
}
}
"#,
)
}
#[test]
fn move_arm_cond_to_match_guard_elseif_in_block() {
cov_mark::check!(move_guard_ifelse_in_block);
check_assist(
move_arm_cond_to_match_guard,
r#"
fn main() {
match 92 {
3 => true,
x => {
if x > $010 {
false
} else if x > 5 {
true
} else if x > 4 {
false
} else {
true
}
}
}
}
"#,
r#"
fn main() {
match 92 {
3 => true,
x if x > 10 => false,
x if x > 5 => true,
x if x > 4 => false,
x => true,
}
}
"#,
)
}
#[test]
fn move_arm_cond_to_match_guard_elseif_chain() {
cov_mark::check!(move_guard_ifelse_else_tail);
check_assist(
move_arm_cond_to_match_guard,
r#"
fn main() {
match 92 {
3 => 0,
x => if x $0> 10 {
1
} else if x > 5 {
2
} else if x > 3 {
42;
3
} else {
4
},
}
}
"#,
r#"
fn main() {
match 92 {
3 => 0,
x if x > 10 => 1,
x if x > 5 => 2,
x if x > 3 => {
42;
3
}
x => 4,
}
}
"#,
)
}
#[test]
fn move_arm_cond_to_match_guard_elseif_iflet() {
check_assist(
move_arm_cond_to_match_guard,
r#"
fn main() {
match 92 {
3 => 0,
x => if x $0> 10 {
1
} else if x > 5 {
2
} else if let 4 = 4 {
42;
3
} else {
4
},
}
}"#,
r#"
fn main() {
match 92 {
3 => 0,
x if x > 10 => 1,
x if x > 5 => 2,
x if let 4 = 4 => {
42;
3
}
x => 4,
}
}"#,
);
}
#[test]
fn move_arm_cond_to_match_guard_elseif_notail() {
cov_mark::check!(move_guard_ifelse_notail);
check_assist(
move_arm_cond_to_match_guard,
r#"
fn main() {
match 92 {
3 => 0,
x => if x > $010 {
1
} else if x > 5 {
2
} else if x > 4 {
42;
3
},
}
}
"#,
r#"
fn main() {
match 92 {
3 => 0,
x if x > 10 => 1,
x if x > 5 => 2,
x if x > 4 => {
42;
3
}
x => {}
}
}
"#,
)
}
}