diff options
Diffstat (limited to '')
-rw-r--r-- | src/tools/rust-analyzer/crates/ide-assists/src/handlers/replace_let_with_if_let.rs | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/replace_let_with_if_let.rs b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/replace_let_with_if_let.rs new file mode 100644 index 000000000..c2be4593b --- /dev/null +++ b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/replace_let_with_if_let.rs @@ -0,0 +1,100 @@ +use std::iter::once; + +use ide_db::ty_filter::TryEnum; +use syntax::{ + ast::{ + self, + edit::{AstNodeEdit, IndentLevel}, + make, + }, + AstNode, T, +}; + +use crate::{AssistContext, AssistId, AssistKind, Assists}; + +// Assist: replace_let_with_if_let +// +// Replaces `let` with an `if let`. +// +// ``` +// # enum Option<T> { Some(T), None } +// +// fn main(action: Action) { +// $0let x = compute(); +// } +// +// fn compute() -> Option<i32> { None } +// ``` +// -> +// ``` +// # enum Option<T> { Some(T), None } +// +// fn main(action: Action) { +// if let Some(x) = compute() { +// } +// } +// +// fn compute() -> Option<i32> { None } +// ``` +pub(crate) fn replace_let_with_if_let(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<()> { + let let_kw = ctx.find_token_syntax_at_offset(T![let])?; + let let_stmt = let_kw.parent().and_then(ast::LetStmt::cast)?; + let init = let_stmt.initializer()?; + let original_pat = let_stmt.pat()?; + + let target = let_kw.text_range(); + acc.add( + AssistId("replace_let_with_if_let", AssistKind::RefactorRewrite), + "Replace let with if let", + target, + |edit| { + let ty = ctx.sema.type_of_expr(&init); + let happy_variant = ty + .and_then(|ty| TryEnum::from_ty(&ctx.sema, &ty.adjusted())) + .map(|it| it.happy_case()); + let pat = match happy_variant { + None => original_pat, + Some(var_name) => { + make::tuple_struct_pat(make::ext::ident_path(var_name), once(original_pat)) + .into() + } + }; + + let block = + make::ext::empty_block_expr().indent(IndentLevel::from_node(let_stmt.syntax())); + let if_ = make::expr_if(make::expr_let(pat, init).into(), block, None); + let stmt = make::expr_stmt(if_); + + edit.replace_ast(ast::Stmt::from(let_stmt), ast::Stmt::from(stmt)); + }, + ) +} + +#[cfg(test)] +mod tests { + use crate::tests::check_assist; + + use super::*; + + #[test] + fn replace_let_unknown_enum() { + check_assist( + replace_let_with_if_let, + r" +enum E<T> { X(T), Y(T) } + +fn main() { + $0let x = E::X(92); +} + ", + r" +enum E<T> { X(T), Y(T) } + +fn main() { + if let x = E::X(92) { + } +} + ", + ) + } +} |