From a624e2ea8d6fc97df03f663581e082541fd0348f Mon Sep 17 00:00:00 2001 From: jake Date: Sun, 11 Apr 2021 00:31:20 -0700 Subject: Adds impl Deref assist --- crates/ide_assists/src/handlers/generate_deref.rs | 143 ++++++++++++++++++++++ crates/ide_assists/src/lib.rs | 2 + crates/ide_assists/src/tests.rs | 1 + crates/ide_assists/src/tests/generated.rs | 27 ++++ crates/ide_db/src/helpers.rs | 4 + crates/ide_db/src/helpers/famous_defs_fixture.rs | 8 ++ 6 files changed, 185 insertions(+) create mode 100644 crates/ide_assists/src/handlers/generate_deref.rs diff --git a/crates/ide_assists/src/handlers/generate_deref.rs b/crates/ide_assists/src/handlers/generate_deref.rs new file mode 100644 index 000000000..a8126e414 --- /dev/null +++ b/crates/ide_assists/src/handlers/generate_deref.rs @@ -0,0 +1,143 @@ +use ide_db::{helpers::FamousDefs, RootDatabase}; +use syntax::{ + ast::{self, NameOwner}, + AstNode, +}; + +use crate::{ + assist_context::{AssistContext, Assists}, + utils::generate_trait_impl_text, + AssistId, AssistKind, +}; + +// Assist: generate_deref +// +// Generate `Deref` impl using the given struct field. +// +// ``` +// struct A; +// struct B { +// $0a: A +// } +// ``` +// -> +// ``` +// struct A; +// struct B { +// a: A +// } +// +// impl std::ops::Deref for B { +// type Target = A; +// +// fn deref(&self) -> &Self::Target { +// &self.a +// } +// } +// ``` +pub(crate) fn generate_deref(acc: &mut Assists, ctx: &AssistContext) -> Option<()> { + let strukt = ctx.find_node_at_offset::()?; + let field = ctx.find_node_at_offset::()?; + + if existing_deref_impl(&ctx.sema, &strukt).is_some() { + cov_mark::hit!(test_add_deref_impl_already_exists); + return None; + } + + let field_type = field.ty()?; + let field_name = field.name()?; + let target = field.syntax().text_range(); + acc.add( + AssistId("generate_deref", AssistKind::Generate), + format!("Generate `Deref` impl using `{}`", field_name), + target, + |edit| { + let start_offset = strukt.syntax().text_range().end(); + let impl_code = format!( + r#" type Target = {0}; + + fn deref(&self) -> &Self::Target {{ + &self.{1} + }}"#, + field_type.syntax(), + field_name.syntax() + ); + let strukt_adt = ast::Adt::Struct(strukt); + // Q for reviewer: Is there a better way to specify the trait_text, e.g. + // - can I have it auto `use std::ops::Deref`, and then just use `Deref` as the trait text? + // Or is there a helper that might detect if `std::ops::Deref` has been used, and pick `Deref`, + // otherwise, pick `std::ops::Deref` for the trait_text. + let deref_impl = generate_trait_impl_text(&strukt_adt, "std::ops::Deref", &impl_code); + edit.insert(start_offset, deref_impl); + }, + ) +} + +fn existing_deref_impl( + sema: &'_ hir::Semantics<'_, RootDatabase>, + strukt: &ast::Struct, +) -> Option<()> { + let strukt = sema.to_def(strukt)?; + let krate = strukt.module(sema.db).krate(); + + let deref_trait = FamousDefs(sema, Some(krate)).core_ops_Deref()?; + let strukt_type = strukt.ty(sema.db); + + if strukt_type.impls_trait(sema.db, deref_trait, &[]) { + Some(()) + } else { + None + } +} + +#[cfg(test)] +mod tests { + use crate::tests::{check_assist, check_assist_not_applicable}; + + use super::*; + + #[test] + fn test_generate_deref() { + check_assist( + generate_deref, + r#"struct A { } +struct B { $0a: A }"#, + r#"struct A { } +struct B { a: A } + +impl std::ops::Deref for B { + type Target = A; + + fn deref(&self) -> &Self::Target { + &self.a + } +}"#, + ); + } + + fn check_not_applicable(ra_fixture: &str) { + let fixture = format!( + "//- /main.rs crate:main deps:core,std\n{}\n{}", + ra_fixture, + FamousDefs::FIXTURE + ); + check_assist_not_applicable(generate_deref, &fixture) + } + + #[test] + fn test_generate_deref_not_applicable_if_already_impl() { + cov_mark::check!(test_add_deref_impl_already_exists); + check_not_applicable( + r#"struct A { } +struct B { $0a: A } + +impl std::ops::Deref for B { + type Target = A; + + fn deref(&self) -> &Self::Target { + &self.a + } +}"#, + ) + } +} diff --git a/crates/ide_assists/src/lib.rs b/crates/ide_assists/src/lib.rs index 3e2c82dac..d6a083e1a 100644 --- a/crates/ide_assists/src/lib.rs +++ b/crates/ide_assists/src/lib.rs @@ -132,6 +132,7 @@ mod handlers { mod generate_default_from_enum_variant; mod generate_default_from_new; mod generate_is_empty_from_len; + mod generate_deref; mod generate_derive; mod generate_enum_is_method; mod generate_enum_projection_method; @@ -199,6 +200,7 @@ mod handlers { generate_default_from_enum_variant::generate_default_from_enum_variant, generate_default_from_new::generate_default_from_new, generate_is_empty_from_len::generate_is_empty_from_len, + generate_deref::generate_deref, generate_derive::generate_derive, generate_enum_is_method::generate_enum_is_method, generate_enum_projection_method::generate_enum_as_method, diff --git a/crates/ide_assists/src/tests.rs b/crates/ide_assists/src/tests.rs index a7a923beb..6f25d3227 100644 --- a/crates/ide_assists/src/tests.rs +++ b/crates/ide_assists/src/tests.rs @@ -191,6 +191,7 @@ fn assist_order_field_struct() { let mut assists = assists.iter(); assert_eq!(assists.next().expect("expected assist").label, "Change visibility to pub(crate)"); + assert_eq!(assists.next().expect("expected assist").label, "Generate `Deref` impl using `bar`"); assert_eq!(assists.next().expect("expected assist").label, "Generate a mut getter method"); assert_eq!(assists.next().expect("expected assist").label, "Generate a getter method"); assert_eq!(assists.next().expect("expected assist").label, "Generate a setter method"); diff --git a/crates/ide_assists/src/tests/generated.rs b/crates/ide_assists/src/tests/generated.rs index 27a22ca10..41559b43a 100644 --- a/crates/ide_assists/src/tests/generated.rs +++ b/crates/ide_assists/src/tests/generated.rs @@ -551,6 +551,33 @@ impl Default for Example { ) } +#[test] +fn doctest_generate_deref() { + check_doc_test( + "generate_deref", + r#####" +struct A; +struct B { + $0a: A +} +"#####, + r#####" +struct A; +struct B { + a: A +} + +impl std::ops::Deref for B { + type Target = A; + + fn deref(&self) -> &Self::Target { + &self.a + } +} +"#####, + ) +} + #[test] fn doctest_generate_derive() { check_doc_test( diff --git a/crates/ide_db/src/helpers.rs b/crates/ide_db/src/helpers.rs index 66798ea3a..83a665b37 100644 --- a/crates/ide_db/src/helpers.rs +++ b/crates/ide_db/src/helpers.rs @@ -113,6 +113,10 @@ impl FamousDefs<'_, '_> { self.find_module("core:iter") } + pub fn core_ops_Deref(&self) -> Option { + self.find_trait("core:ops:Deref") + } + fn find_trait(&self, path: &str) -> Option { match self.find_def(path)? { hir::ScopeDef::ModuleDef(hir::ModuleDef::Trait(it)) => Some(it), diff --git a/crates/ide_db/src/helpers/famous_defs_fixture.rs b/crates/ide_db/src/helpers/famous_defs_fixture.rs index 4d79e064e..29ae12dcf 100644 --- a/crates/ide_db/src/helpers/famous_defs_fixture.rs +++ b/crates/ide_db/src/helpers/famous_defs_fixture.rs @@ -112,6 +112,12 @@ pub mod ops { type Output; extern "rust-call" fn call_once(self, args: Args) -> Self::Output; } + + #[lang = "deref"] + pub trait Deref { + type Target: ?Sized; + fn deref(&self) -> &Self::Target; + } } pub mod option { @@ -141,3 +147,5 @@ mod return_keyword {} /// Docs for prim_str mod prim_str {} + +pub use core::ops; \ No newline at end of file -- cgit v1.2.3