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|
use ra_fmt::unwrap_trivial_block;
use ra_syntax::{
ast::{
self,
edit::{AstNodeEdit, IndentLevel},
make,
},
AstNode,
};
use crate::{utils::TryEnum, AssistContext, AssistId, Assists};
// Assist: replace_if_let_with_match
//
// Replaces `if let` with an else branch with a `match` expression.
//
// ```
// enum Action { Move { distance: u32 }, Stop }
//
// fn handle(action: Action) {
// <|>if let Action::Move { distance } = action {
// foo(distance)
// } else {
// bar()
// }
// }
// ```
// ->
// ```
// enum Action { Move { distance: u32 }, Stop }
//
// fn handle(action: Action) {
// match action {
// Action::Move { distance } => foo(distance),
// _ => bar(),
// }
// }
// ```
pub(crate) fn replace_if_let_with_match(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
let if_expr: ast::IfExpr = ctx.find_node_at_offset()?;
let cond = if_expr.condition()?;
let pat = cond.pat()?;
let expr = cond.expr()?;
let then_block = if_expr.then_branch()?;
let else_block = match if_expr.else_branch()? {
ast::ElseBranch::Block(it) => it,
ast::ElseBranch::IfExpr(_) => return None,
};
let target = if_expr.syntax().text_range();
acc.add(AssistId("replace_if_let_with_match"), "Replace with match", target, move |edit| {
let match_expr = {
let then_arm = {
let then_expr = unwrap_trivial_block(then_block);
make::match_arm(vec![pat.clone()], then_expr)
};
let else_arm = {
let pattern = ctx
.sema
.type_of_pat(&pat)
.and_then(|ty| TryEnum::from_ty(&ctx.sema, &ty))
.map(|it| it.sad_pattern())
.unwrap_or_else(|| make::placeholder_pat().into());
let else_expr = unwrap_trivial_block(else_block);
make::match_arm(vec![pattern], else_expr)
};
make::expr_match(expr, make::match_arm_list(vec![then_arm, else_arm]))
.indent(IndentLevel::from_node(if_expr.syntax()))
};
edit.set_cursor(if_expr.syntax().text_range().start());
edit.replace_ast::<ast::Expr>(if_expr.into(), match_expr);
})
}
#[cfg(test)]
mod tests {
use super::*;
use crate::tests::{check_assist, check_assist_target};
#[test]
fn test_replace_if_let_with_match_unwraps_simple_expressions() {
check_assist(
replace_if_let_with_match,
"
impl VariantData {
pub fn is_struct(&self) -> bool {
if <|>let VariantData::Struct(..) = *self {
true
} else {
false
}
}
} ",
"
impl VariantData {
pub fn is_struct(&self) -> bool {
<|>match *self {
VariantData::Struct(..) => true,
_ => false,
}
}
} ",
)
}
#[test]
fn test_replace_if_let_with_match_doesnt_unwrap_multiline_expressions() {
check_assist(
replace_if_let_with_match,
"
fn foo() {
if <|>let VariantData::Struct(..) = a {
bar(
123
)
} else {
false
}
} ",
"
fn foo() {
<|>match a {
VariantData::Struct(..) => {
bar(
123
)
}
_ => false,
}
} ",
)
}
#[test]
fn replace_if_let_with_match_target() {
check_assist_target(
replace_if_let_with_match,
"
impl VariantData {
pub fn is_struct(&self) -> bool {
if <|>let VariantData::Struct(..) = *self {
true
} else {
false
}
}
} ",
"if let VariantData::Struct(..) = *self {
true
} else {
false
}",
);
}
#[test]
fn special_case_option() {
check_assist(
replace_if_let_with_match,
r#"
enum Option<T> { Some(T), None }
use Option::*;
fn foo(x: Option<i32>) {
<|>if let Some(x) = x {
println!("{}", x)
} else {
println!("none")
}
}
"#,
r#"
enum Option<T> { Some(T), None }
use Option::*;
fn foo(x: Option<i32>) {
<|>match x {
Some(x) => println!("{}", x),
None => println!("none"),
}
}
"#,
);
}
#[test]
fn special_case_result() {
check_assist(
replace_if_let_with_match,
r#"
enum Result<T, E> { Ok(T), Err(E) }
use Result::*;
fn foo(x: Result<i32, ()>) {
<|>if let Ok(x) = x {
println!("{}", x)
} else {
println!("none")
}
}
"#,
r#"
enum Result<T, E> { Ok(T), Err(E) }
use Result::*;
fn foo(x: Result<i32, ()>) {
<|>match x {
Ok(x) => println!("{}", x),
Err(_) => println!("none"),
}
}
"#,
);
}
}
|
