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|
use format_buf::format;
use hir::db::HirDatabase;
use ra_fmt::extract_trivial_expression;
use ra_syntax::{ast, AstNode};
use crate::{Assist, AssistCtx, AssistId};
// 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(mut ctx: AssistCtx<impl HirDatabase>) -> Option<Assist> {
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,
};
ctx.add_action(AssistId("replace_if_let_with_match"), "replace with match", |edit| {
let match_expr = build_match_expr(expr, pat, then_block, else_block);
edit.target(if_expr.syntax().text_range());
edit.replace_node_and_indent(if_expr.syntax(), match_expr);
edit.set_cursor(if_expr.syntax().text_range().start())
});
ctx.build()
}
fn build_match_expr(
expr: ast::Expr,
pat1: ast::Pat,
arm1: ast::BlockExpr,
arm2: ast::BlockExpr,
) -> String {
let mut buf = String::new();
format!(buf, "match {} {{\n", expr.syntax().text());
format!(buf, " {} => {}\n", pat1.syntax().text(), format_arm(&arm1));
format!(buf, " _ => {}\n", format_arm(&arm2));
buf.push_str("}");
buf
}
fn format_arm(block: &ast::BlockExpr) -> String {
match extract_trivial_expression(block) {
None => block.syntax().text().to_string(),
Some(e) => format!("{},", e.syntax().text()),
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::helpers::{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 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
}",
);
}
}
|
