From 98a626450d43515f8fe91db9f7918c6e69804693 Mon Sep 17 00:00:00 2001 From: Matt Hall Date: Tue, 23 Feb 2021 19:19:48 +0000 Subject: Address review comments * Move code to build replacement into closure * Look for iter/iter_mut methods on types behind reference --- .../src/handlers/convert_for_to_iter_for_each.rs | 158 ++++++++++++++++----- 1 file changed, 125 insertions(+), 33 deletions(-) (limited to 'crates/ide_assists') diff --git a/crates/ide_assists/src/handlers/convert_for_to_iter_for_each.rs b/crates/ide_assists/src/handlers/convert_for_to_iter_for_each.rs index d858474c6..f329d435f 100644 --- a/crates/ide_assists/src/handlers/convert_for_to_iter_for_each.rs +++ b/crates/ide_assists/src/handlers/convert_for_to_iter_for_each.rs @@ -32,33 +32,68 @@ pub(crate) fn convert_for_to_iter_for_each(acc: &mut Assists, ctx: &AssistContex let pat = for_loop.pat()?; let body = for_loop.loop_body()?; - let mut buf = String::new(); + acc.add( + AssistId("convert_for_to_iter_for_each", AssistKind::RefactorRewrite), + "Convert a for loop into an Iterator::for_each", + for_loop.syntax().text_range(), + |builder| { + let mut buf = String::new(); - if impls_core_iter(&ctx.sema, &iterable) { - buf += &iterable.to_string(); - } else { - match iterable { - ast::Expr::RefExpr(r) => { - if r.mut_token().is_some() { - format_to!(buf, "{}.iter_mut()", r.expr()?); + if let Some((expr_behind_ref, method)) = + is_ref_and_impls_iter_method(&ctx.sema, &iterable) + { + // We have either "for x in &col" and col implements a method called iter + // or "for x in &mut col" and col implements a method called iter_mut + format_to!(buf, "{}.{}()", expr_behind_ref, method); + } else if impls_core_iter(&ctx.sema, &iterable) { + format_to!(buf, "{}", iterable); + } else { + if let ast::Expr::RefExpr(_) = iterable { + format_to!(buf, "({}).into_iter()", iterable); } else { - format_to!(buf, "{}.iter()", r.expr()?); + format_to!(buf, "{}.into_iter()", iterable); } } - _ => format_to!(buf, "{}.into_iter()", iterable), - } - } - format_to!(buf, ".for_each(|{}| {});", pat, body); + format_to!(buf, ".for_each(|{}| {});", pat, body); - acc.add( - AssistId("convert_for_to_iter_for_each", AssistKind::RefactorRewrite), - "Convert a for loop into an Iterator::for_each", - for_loop.syntax().text_range(), - |builder| builder.replace(for_loop.syntax().text_range(), buf), + builder.replace(for_loop.syntax().text_range(), buf) + }, ) } +/// If iterable is a reference where the expression behind the reference implements a method +/// returning an Iterator called iter or iter_mut (depending on the type of reference) then return +/// the expression behind the reference and the method name +fn is_ref_and_impls_iter_method( + sema: &hir::Semantics, + iterable: &ast::Expr, +) -> Option<(ast::Expr, &'static str)> { + let ref_expr = match iterable { + ast::Expr::RefExpr(r) => r, + _ => return None, + }; + let wanted_method = if ref_expr.mut_token().is_some() { "iter_mut" } else { "iter" }; + let expr_behind_ref = ref_expr.expr()?; + let typ = sema.type_of_expr(&expr_behind_ref)?; + let scope = sema.scope(iterable.syntax()); + let krate = scope.module()?.krate(); + let traits_in_scope = scope.traits_in_scope(); + let iter_trait = FamousDefs(sema, Some(krate)).core_iter_Iterator()?; + let has_wanted_method = + typ.iterate_method_candidates(sema.db, krate, &traits_in_scope, None, |_, func| { + if func.name(sema.db).to_string() != wanted_method { + return None; + } + if func.ret_type(sema.db).impls_trait(sema.db, iter_trait, &[]) { + return Some(()); + } + None + }); + has_wanted_method.and(Some((expr_behind_ref, wanted_method))) +} + +/// Whether iterable implements core::Iterator fn impls_core_iter(sema: &hir::Semantics, iterable: &ast::Expr) -> bool { let it_typ = if let Some(i) = sema.type_of_expr(iterable) { i @@ -94,7 +129,10 @@ impl Iterator for EmptyIter { pub struct Empty; impl Empty { pub fn iter(&self) -> EmptyIter { EmptyIter } + pub fn iter_mut(&self) -> EmptyIter { EmptyIter } } + +pub struct NoIterMethod; "; #[test] @@ -131,43 +169,97 @@ fn main() { #[test] fn test_for_borrowed() { - check_assist( - convert_for_to_iter_for_each, - r" + let before = r" +use empty_iter::*; fn main() { - let x = vec![1, 2, 3]; + let x = Empty; for $0v in &x { let a = v * 2; } -}", +} +"; + let before = &format!( + "//- /main.rs crate:main deps:core,empty_iter{}{}{}", + before, + FamousDefs::FIXTURE, + EMPTY_ITER_FIXTURE + ); + check_assist( + convert_for_to_iter_for_each, + before, r" +use empty_iter::*; fn main() { - let x = vec![1, 2, 3]; + let x = Empty; x.iter().for_each(|v| { let a = v * 2; }); -}", +} +", ) } #[test] - fn test_for_borrowed_mut() { + fn test_for_borrowed_no_iter_method() { + let before = r" +use empty_iter::*; +fn main() { + let x = NoIterMethod; + for $0v in &x { + let a = v * 2; + } +} +"; + let before = &format!( + "//- /main.rs crate:main deps:core,empty_iter{}{}{}", + before, + FamousDefs::FIXTURE, + EMPTY_ITER_FIXTURE + ); check_assist( convert_for_to_iter_for_each, + before, r" +use empty_iter::*; fn main() { - let x = vec![1, 2, 3]; + let x = NoIterMethod; + (&x).into_iter().for_each(|v| { + let a = v * 2; + }); +} +", + ) + } + + #[test] + fn test_for_borrowed_mut() { + let before = r" +use empty_iter::*; +fn main() { + let x = Empty; for $0v in &mut x { - *v *= 2; + let a = v * 2; } -}", +} +"; + let before = &format!( + "//- /main.rs crate:main deps:core,empty_iter{}{}{}", + before, + FamousDefs::FIXTURE, + EMPTY_ITER_FIXTURE + ); + check_assist( + convert_for_to_iter_for_each, + before, r" +use empty_iter::*; fn main() { - let x = vec![1, 2, 3]; + let x = Empty; x.iter_mut().for_each(|v| { - *v *= 2; + let a = v * 2; }); -}", +} +", ) } @@ -195,7 +287,7 @@ fn main() { } #[test] - fn test_take() { + fn test_already_impls_iterator() { let before = r#" use empty_iter::*; fn main() { -- cgit v1.2.3