101 lines
2.3 KiB
Rust
101 lines
2.3 KiB
Rust
use std::iter::once;
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use ide_db::ty_filter::TryEnum;
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use syntax::{
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ast::{
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self,
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edit::{AstNodeEdit, IndentLevel},
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make,
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},
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AstNode, T,
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};
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use crate::{AssistContext, AssistId, AssistKind, Assists};
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// Assist: replace_let_with_if_let
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//
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// Replaces `let` with an `if let`.
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//
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// ```
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// # enum Option<T> { Some(T), None }
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//
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// fn main(action: Action) {
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// $0let x = compute();
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// }
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//
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// fn compute() -> Option<i32> { None }
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// ```
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// ->
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// ```
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// # enum Option<T> { Some(T), None }
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//
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// fn main(action: Action) {
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// if let Some(x) = compute() {
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// }
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// }
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//
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// fn compute() -> Option<i32> { None }
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// ```
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pub(crate) fn replace_let_with_if_let(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<()> {
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let let_kw = ctx.find_token_syntax_at_offset(T![let])?;
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let let_stmt = let_kw.parent().and_then(ast::LetStmt::cast)?;
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let init = let_stmt.initializer()?;
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let original_pat = let_stmt.pat()?;
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let target = let_kw.text_range();
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acc.add(
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AssistId("replace_let_with_if_let", AssistKind::RefactorRewrite),
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"Replace let with if let",
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target,
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|edit| {
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let ty = ctx.sema.type_of_expr(&init);
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let happy_variant = ty
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.and_then(|ty| TryEnum::from_ty(&ctx.sema, &ty.adjusted()))
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.map(|it| it.happy_case());
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let pat = match happy_variant {
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None => original_pat,
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Some(var_name) => {
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make::tuple_struct_pat(make::ext::ident_path(var_name), once(original_pat))
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.into()
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}
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};
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let block =
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make::ext::empty_block_expr().indent(IndentLevel::from_node(let_stmt.syntax()));
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let if_ = make::expr_if(make::expr_let(pat, init).into(), block, None);
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let stmt = make::expr_stmt(if_);
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edit.replace_ast(ast::Stmt::from(let_stmt), ast::Stmt::from(stmt));
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},
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)
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}
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#[cfg(test)]
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mod tests {
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use crate::tests::check_assist;
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use super::*;
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#[test]
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fn replace_let_unknown_enum() {
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check_assist(
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replace_let_with_if_let,
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r"
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enum E<T> { X(T), Y(T) }
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fn main() {
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$0let x = E::X(92);
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}
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",
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r"
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enum E<T> { X(T), Y(T) }
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fn main() {
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if let x = E::X(92) {
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}
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}
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",
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)
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}
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}
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