From 406d96c7d4c3a78d42b58a91ba633333ec37d487 Mon Sep 17 00:00:00 2001 From: Aleksey Kladov Date: Sun, 28 Feb 2021 21:11:41 +0300 Subject: Use consistent naming for assist --- .../src/handlers/replace_for_loop_with_for_each.rs | 321 +++++++++++++++++++++ 1 file changed, 321 insertions(+) create mode 100644 crates/ide_assists/src/handlers/replace_for_loop_with_for_each.rs (limited to 'crates/ide_assists/src/handlers/replace_for_loop_with_for_each.rs') diff --git a/crates/ide_assists/src/handlers/replace_for_loop_with_for_each.rs b/crates/ide_assists/src/handlers/replace_for_loop_with_for_each.rs new file mode 100644 index 000000000..27da28bc0 --- /dev/null +++ b/crates/ide_assists/src/handlers/replace_for_loop_with_for_each.rs @@ -0,0 +1,321 @@ +use ast::LoopBodyOwner; +use hir::known; +use ide_db::helpers::FamousDefs; +use stdx::format_to; +use syntax::{ast, AstNode}; +use test_utils::mark; + +use crate::{AssistContext, AssistId, AssistKind, Assists}; + +// Assist: replace_for_loop_with_for_each +// +// Converts a for loop into a for_each loop on the Iterator. +// +// ``` +// fn main() { +// let x = vec![1, 2, 3]; +// for$0 v in x { +// let y = v * 2; +// } +// } +// ``` +// -> +// ``` +// fn main() { +// let x = vec![1, 2, 3]; +// x.into_iter().for_each(|v| { +// let y = v * 2; +// }); +// } +// ``` +pub(crate) fn replace_for_loop_with_for_each(acc: &mut Assists, ctx: &AssistContext) -> Option<()> { + let for_loop = ctx.find_node_at_offset::()?; + let iterable = for_loop.iterable()?; + let pat = for_loop.pat()?; + let body = for_loop.loop_body()?; + if body.syntax().text_range().start() < ctx.offset() { + mark::hit!(not_available_in_body); + return None; + } + + acc.add( + AssistId("replace_for_loop_with_for_each", AssistKind::RefactorRewrite), + "Replace this for loop with `Iterator::for_each`", + for_loop.syntax().text_range(), + |builder| { + let mut buf = String::new(); + + 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, "{}.into_iter()", iterable); + } + } + + format_to!(buf, ".for_each(|{}| {});", pat, body); + + 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, hir::Name)> { + let ref_expr = match iterable { + ast::Expr::RefExpr(r) => r, + _ => return None, + }; + let wanted_method = if ref_expr.mut_token().is_some() { known::iter_mut } else { known::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, + Some(&wanted_method), + |_, func| { + 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 + } else { + return false; + }; + let module = if let Some(m) = sema.scope(iterable.syntax()).module() { + m + } else { + return false; + }; + let krate = module.krate(); + if let Some(iter_trait) = FamousDefs(sema, Some(krate)).core_iter_Iterator() { + return it_typ.impls_trait(sema.db, iter_trait, &[]); + } + false +} + +#[cfg(test)] +mod tests { + use crate::tests::{check_assist, check_assist_not_applicable}; + + use super::*; + + const EMPTY_ITER_FIXTURE: &'static str = r" +//- /lib.rs deps:core crate:empty_iter +pub struct EmptyIter; +impl Iterator for EmptyIter { + type Item = usize; + fn next(&mut self) -> Option { None } +} + +pub struct Empty; +impl Empty { + pub fn iter(&self) -> EmptyIter { EmptyIter } + pub fn iter_mut(&self) -> EmptyIter { EmptyIter } +} + +pub struct NoIterMethod; +"; + + fn check_assist_with_fixtures(before: &str, after: &str) { + let before = &format!( + "//- /main.rs crate:main deps:core,empty_iter{}{}{}", + before, + FamousDefs::FIXTURE, + EMPTY_ITER_FIXTURE + ); + check_assist(replace_for_loop_with_for_each, before, after); + } + + #[test] + fn test_not_for() { + check_assist_not_applicable( + replace_for_loop_with_for_each, + r" +let mut x = vec![1, 2, 3]; +x.iter_mut().$0for_each(|v| *v *= 2); + ", + ) + } + + #[test] + fn test_simple_for() { + check_assist( + replace_for_loop_with_for_each, + r" +fn main() { + let x = vec![1, 2, 3]; + for $0v in x { + v *= 2; + } +}", + r" +fn main() { + let x = vec![1, 2, 3]; + x.into_iter().for_each(|v| { + v *= 2; + }); +}", + ) + } + + #[test] + fn not_available_in_body() { + mark::check!(not_available_in_body); + check_assist_not_applicable( + replace_for_loop_with_for_each, + r" +fn main() { + let x = vec![1, 2, 3]; + for v in x { + $0v *= 2; + } +}", + ) + } + + #[test] + fn test_for_borrowed() { + check_assist_with_fixtures( + r" +use empty_iter::*; +fn main() { + let x = Empty; + for $0v in &x { + let a = v * 2; + } +} +", + r" +use empty_iter::*; +fn main() { + let x = Empty; + x.iter().for_each(|v| { + let a = v * 2; + }); +} +", + ) + } + + #[test] + fn test_for_borrowed_no_iter_method() { + check_assist_with_fixtures( + r" +use empty_iter::*; +fn main() { + let x = NoIterMethod; + for $0v in &x { + let a = v * 2; + } +} +", + r" +use empty_iter::*; +fn main() { + let x = NoIterMethod; + (&x).into_iter().for_each(|v| { + let a = v * 2; + }); +} +", + ) + } + + #[test] + fn test_for_borrowed_mut() { + check_assist_with_fixtures( + r" +use empty_iter::*; +fn main() { + let x = Empty; + for $0v in &mut x { + let a = v * 2; + } +} +", + r" +use empty_iter::*; +fn main() { + let x = Empty; + x.iter_mut().for_each(|v| { + let a = v * 2; + }); +} +", + ) + } + + #[test] + fn test_for_borrowed_mut_behind_var() { + check_assist( + replace_for_loop_with_for_each, + r" +fn main() { + let x = vec![1, 2, 3]; + let y = &mut x; + for $0v in y { + *v *= 2; + } +}", + r" +fn main() { + let x = vec![1, 2, 3]; + let y = &mut x; + y.into_iter().for_each(|v| { + *v *= 2; + }); +}", + ) + } + + #[test] + fn test_already_impls_iterator() { + check_assist_with_fixtures( + r#" +use empty_iter::*; +fn main() { + let x = Empty; + for$0 a in x.iter().take(1) { + println!("{}", a); + } +} +"#, + r#" +use empty_iter::*; +fn main() { + let x = Empty; + x.iter().take(1).for_each(|a| { + println!("{}", a); + }); +} +"#, + ); + } +} -- cgit v1.2.3