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Diffstat (limited to 'crates/ide-assists/src/handlers/desugar_try_expr.rs')
| -rw-r--r-- | crates/ide-assists/src/handlers/desugar_try_expr.rs | 281 |
1 files changed, 281 insertions, 0 deletions
diff --git a/crates/ide-assists/src/handlers/desugar_try_expr.rs b/crates/ide-assists/src/handlers/desugar_try_expr.rs new file mode 100644 index 0000000000..efadde9e36 --- /dev/null +++ b/crates/ide-assists/src/handlers/desugar_try_expr.rs @@ -0,0 +1,281 @@ +use std::iter; + +use ide_db::{ + assists::{AssistId, ExprFillDefaultMode}, + ty_filter::TryEnum, +}; +use syntax::{ + AstNode, T, + ast::{ + self, + edit::{AstNodeEdit, IndentLevel}, + make, + syntax_factory::SyntaxFactory, + }, +}; + +use crate::assist_context::{AssistContext, Assists}; + +// Assist: desugar_try_expr_match +// +// Replaces a `try` expression with a `match` expression. +// +// ``` +// # //- minicore: try, option +// fn handle() { +// let pat = Some(true)$0?; +// } +// ``` +// -> +// ``` +// fn handle() { +// let pat = match Some(true) { +// Some(it) => it, +// None => return None, +// }; +// } +// ``` + +// Assist: desugar_try_expr_let_else +// +// Replaces a `try` expression with a `let else` statement. +// +// ``` +// # //- minicore: try, option +// fn handle() { +// let pat = Some(true)$0?; +// } +// ``` +// -> +// ``` +// fn handle() { +// let Some(pat) = Some(true) else { +// return None; +// }; +// } +// ``` +pub(crate) fn desugar_try_expr(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<()> { + let question_tok = ctx.find_token_syntax_at_offset(T![?])?; + let try_expr = question_tok.parent().and_then(ast::TryExpr::cast)?; + + let expr = try_expr.expr()?; + let expr_type_info = ctx.sema.type_of_expr(&expr)?; + + let try_enum = TryEnum::from_ty(&ctx.sema, &expr_type_info.original)?; + + let target = try_expr.syntax().text_range(); + acc.add( + AssistId::refactor_rewrite("desugar_try_expr_match"), + "Replace try expression with match", + target, + |edit| { + let sad_pat = match try_enum { + TryEnum::Option => make::path_pat(make::ext::ident_path("None")), + TryEnum::Result => make::tuple_struct_pat( + make::ext::ident_path("Err"), + iter::once(make::path_pat(make::ext::ident_path("err"))), + ) + .into(), + }; + let sad_expr = match try_enum { + TryEnum::Option => { + make::expr_return(Some(make::expr_path(make::ext::ident_path("None")))) + } + TryEnum::Result => make::expr_return(Some( + make::expr_call( + make::expr_path(make::ext::ident_path("Err")), + make::arg_list(iter::once(make::expr_path(make::ext::ident_path("err")))), + ) + .into(), + )), + }; + + let happy_arm = make::match_arm( + try_enum.happy_pattern(make::ident_pat(false, false, make::name("it")).into()), + None, + make::expr_path(make::ext::ident_path("it")), + ); + let sad_arm = make::match_arm(sad_pat, None, sad_expr); + + let match_arm_list = make::match_arm_list([happy_arm, sad_arm]); + + let expr_match = make::expr_match(expr.clone(), match_arm_list) + .indent(IndentLevel::from_node(try_expr.syntax())); + + edit.replace_ast::<ast::Expr>(try_expr.clone().into(), expr_match.into()); + }, + ); + + if let Some(let_stmt) = try_expr.syntax().parent().and_then(ast::LetStmt::cast) { + if let_stmt.let_else().is_none() { + let pat = let_stmt.pat()?; + acc.add( + AssistId::refactor_rewrite("desugar_try_expr_let_else"), + "Replace try expression with let else", + target, + |builder| { + let make = SyntaxFactory::with_mappings(); + let mut editor = builder.make_editor(let_stmt.syntax()); + + let indent_level = IndentLevel::from_node(let_stmt.syntax()); + let new_let_stmt = make.let_else_stmt( + try_enum.happy_pattern(pat), + let_stmt.ty(), + expr, + make.block_expr( + iter::once( + make.expr_stmt( + make.expr_return(Some(match try_enum { + TryEnum::Option => make.expr_path(make.ident_path("None")), + TryEnum::Result => make + .expr_call( + make.expr_path(make.ident_path("Err")), + make.arg_list(iter::once( + match ctx.config.expr_fill_default { + ExprFillDefaultMode::Todo => make + .expr_macro( + make.ident_path("todo"), + make.token_tree( + syntax::SyntaxKind::L_PAREN, + [], + ), + ) + .into(), + ExprFillDefaultMode::Underscore => { + make.expr_underscore().into() + } + ExprFillDefaultMode::Default => make + .expr_macro( + make.ident_path("todo"), + make.token_tree( + syntax::SyntaxKind::L_PAREN, + [], + ), + ) + .into(), + }, + )), + ) + .into(), + })) + .indent(indent_level + 1) + .into(), + ) + .into(), + ), + None, + ) + .indent(indent_level), + ); + editor.replace(let_stmt.syntax(), new_let_stmt.syntax()); + editor.add_mappings(make.finish_with_mappings()); + builder.add_file_edits(ctx.vfs_file_id(), editor); + }, + ); + } + } + Some(()) +} + +#[cfg(test)] +mod tests { + use super::*; + + use crate::tests::{check_assist, check_assist_by_label, check_assist_not_applicable}; + + #[test] + fn test_desugar_try_expr_not_applicable() { + check_assist_not_applicable( + desugar_try_expr, + r#" + fn test() { + let pat: u32 = 25$0; + } + "#, + ); + } + + #[test] + fn test_desugar_try_expr_option() { + check_assist( + desugar_try_expr, + r#" +//- minicore: try, option +fn test() { + let pat = Some(true)$0?; +} + "#, + r#" +fn test() { + let pat = match Some(true) { + Some(it) => it, + None => return None, + }; +} + "#, + ); + } + + #[test] + fn test_desugar_try_expr_result() { + check_assist( + desugar_try_expr, + r#" +//- minicore: try, from, result +fn test() { + let pat = Ok(true)$0?; +} + "#, + r#" +fn test() { + let pat = match Ok(true) { + Ok(it) => it, + Err(err) => return Err(err), + }; +} + "#, + ); + } + + #[test] + fn test_desugar_try_expr_option_let_else() { + check_assist_by_label( + desugar_try_expr, + r#" +//- minicore: try, option +fn test() { + let pat = Some(true)$0?; +} + "#, + r#" +fn test() { + let Some(pat) = Some(true) else { + return None; + }; +} + "#, + "Replace try expression with let else", + ); + } + + #[test] + fn test_desugar_try_expr_result_let_else() { + check_assist_by_label( + desugar_try_expr, + r#" +//- minicore: try, from, result +fn test() { + let pat = Ok(true)$0?; +} + "#, + r#" +fn test() { + let Ok(pat) = Ok(true) else { + return Err(todo!()); + }; +} + "#, + "Replace try expression with let else", + ); + } +} |