diff options
| -rw-r--r-- | clippy_lints/src/from_over_into.rs | 176 | ||||
| -rw-r--r-- | tests/ui/from_over_into.fixed | 62 | ||||
| -rw-r--r-- | tests/ui/from_over_into.rs | 41 | ||||
| -rw-r--r-- | tests/ui/from_over_into.stderr | 57 | ||||
| -rw-r--r-- | tests/ui/from_over_into_unfixable.rs | 35 | ||||
| -rw-r--r-- | tests/ui/from_over_into_unfixable.stderr | 29 |
6 files changed, 375 insertions, 25 deletions
diff --git a/clippy_lints/src/from_over_into.rs b/clippy_lints/src/from_over_into.rs index 5d25c1d0634..95eda4ea882 100644 --- a/clippy_lints/src/from_over_into.rs +++ b/clippy_lints/src/from_over_into.rs @@ -1,11 +1,19 @@ -use clippy_utils::diagnostics::span_lint_and_help; -use clippy_utils::{meets_msrv, msrvs}; -use if_chain::if_chain; -use rustc_hir as hir; +use clippy_utils::diagnostics::span_lint_and_then; +use clippy_utils::macros::span_is_local; +use clippy_utils::source::snippet_opt; +use clippy_utils::{meets_msrv, msrvs, path_def_id}; +use rustc_errors::Applicability; +use rustc_hir::intravisit::{walk_path, Visitor}; +use rustc_hir::{ + GenericArg, GenericArgs, HirId, Impl, ImplItemKind, ImplItemRef, Item, ItemKind, PatKind, Path, PathSegment, Ty, + TyKind, +}; use rustc_lint::{LateContext, LateLintPass}; +use rustc_middle::hir::nested_filter::OnlyBodies; use rustc_semver::RustcVersion; use rustc_session::{declare_tool_lint, impl_lint_pass}; -use rustc_span::symbol::sym; +use rustc_span::symbol::{kw, sym}; +use rustc_span::{Span, Symbol}; declare_clippy_lint! { /// ### What it does @@ -54,28 +62,152 @@ impl FromOverInto { impl_lint_pass!(FromOverInto => [FROM_OVER_INTO]); impl<'tcx> LateLintPass<'tcx> for FromOverInto { - fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::Item<'_>) { - if !meets_msrv(self.msrv, msrvs::RE_REBALANCING_COHERENCE) { + fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'_>) { + if !meets_msrv(self.msrv, msrvs::RE_REBALANCING_COHERENCE) || !span_is_local(item.span) { return; } - if_chain! { - if let hir::ItemKind::Impl{ .. } = &item.kind; - if let Some(impl_trait_ref) = cx.tcx.impl_trait_ref(item.def_id); - if cx.tcx.is_diagnostic_item(sym::Into, impl_trait_ref.def_id); - - then { - span_lint_and_help( - cx, - FROM_OVER_INTO, - cx.tcx.sess.source_map().guess_head_span(item.span), - "an implementation of `From` is preferred since it gives you `Into<_>` for free where the reverse isn't true", - None, - &format!("consider to implement `From<{}>` instead", impl_trait_ref.self_ty()), - ); - } + if let ItemKind::Impl(Impl { + of_trait: Some(hir_trait_ref), + self_ty, + items: [impl_item_ref], + .. + }) = item.kind + && let Some(into_trait_seg) = hir_trait_ref.path.segments.last() + // `impl Into<target_ty> for self_ty` + && let Some(GenericArgs { args: [GenericArg::Type(target_ty)], .. }) = into_trait_seg.args + && let Some(middle_trait_ref) = cx.tcx.impl_trait_ref(item.def_id) + && cx.tcx.is_diagnostic_item(sym::Into, middle_trait_ref.def_id) + { + span_lint_and_then( + cx, + FROM_OVER_INTO, + cx.tcx.sess.source_map().guess_head_span(item.span), + "an implementation of `From` is preferred since it gives you `Into<_>` for free where the reverse isn't true", + |diag| { + // If the target type is likely foreign mention the orphan rules as it's a common source of confusion + if path_def_id(cx, target_ty.peel_refs()).map_or(true, |id| !id.is_local()) { + diag.help( + "`impl From<Local> for Foreign` is allowed by the orphan rules, for more information see\n\ + https://doc.rust-lang.org/reference/items/implementations.html#trait-implementation-coherence" + ); + } + + let message = format!("replace the `Into` implentation with `From<{}>`", middle_trait_ref.self_ty()); + if let Some(suggestions) = convert_to_from(cx, into_trait_seg, target_ty, self_ty, impl_item_ref) { + diag.multipart_suggestion(message, suggestions, Applicability::MachineApplicable); + } else { + diag.help(message); + } + }, + ); } } extract_msrv_attr!(LateContext); } + +/// Finds the occurences of `Self` and `self` +struct SelfFinder<'a, 'tcx> { + cx: &'a LateContext<'tcx>, + /// Occurences of `Self` + upper: Vec<Span>, + /// Occurences of `self` + lower: Vec<Span>, + /// If any of the `self`/`Self` usages were from an expansion, or the body contained a binding + /// already named `val` + invalid: bool, +} + +impl<'a, 'tcx> Visitor<'tcx> for SelfFinder<'a, 'tcx> { + type NestedFilter = OnlyBodies; + + fn nested_visit_map(&mut self) -> Self::Map { + self.cx.tcx.hir() + } + + fn visit_path(&mut self, path: &'tcx Path<'tcx>, _id: HirId) { + for segment in path.segments { + match segment.ident.name { + kw::SelfLower => self.lower.push(segment.ident.span), + kw::SelfUpper => self.upper.push(segment.ident.span), + _ => continue, + } + } + + self.invalid |= path.span.from_expansion(); + if !self.invalid { + walk_path(self, path); + } + } + + fn visit_name(&mut self, name: Symbol) { + if name == sym::val { + self.invalid = true; + } + } +} + +fn convert_to_from( + cx: &LateContext<'_>, + into_trait_seg: &PathSegment<'_>, + target_ty: &Ty<'_>, + self_ty: &Ty<'_>, + impl_item_ref: &ImplItemRef, +) -> Option<Vec<(Span, String)>> { + let impl_item = cx.tcx.hir().impl_item(impl_item_ref.id); + let ImplItemKind::Fn(ref sig, body_id) = impl_item.kind else { return None }; + let body = cx.tcx.hir().body(body_id); + let [input] = body.params else { return None }; + let PatKind::Binding(.., self_ident, None) = input.pat.kind else { return None }; + + let from = snippet_opt(cx, self_ty.span)?; + let into = snippet_opt(cx, target_ty.span)?; + + let mut suggestions = vec![ + // impl Into<T> for U -> impl From<T> for U + // ~~~~ ~~~~ + (into_trait_seg.ident.span, String::from("From")), + // impl Into<T> for U -> impl Into<U> for U + // ~ ~ + (target_ty.span, from.clone()), + // impl Into<T> for U -> impl Into<T> for T + // ~ ~ + (self_ty.span, into), + // fn into(self) -> T -> fn from(self) -> T + // ~~~~ ~~~~ + (impl_item.ident.span, String::from("from")), + // fn into([mut] self) -> T -> fn into([mut] v: T) -> T + // ~~~~ ~~~~ + (self_ident.span, format!("val: {from}")), + // fn into(self) -> T -> fn into(self) -> Self + // ~ ~~~~ + (sig.decl.output.span(), String::from("Self")), + ]; + + let mut finder = SelfFinder { + cx, + upper: Vec::new(), + lower: Vec::new(), + invalid: false, + }; + finder.visit_expr(body.value); + + if finder.invalid { + return None; + } + + // don't try to replace e.g. `Self::default()` with `&[T]::default()` + if !finder.upper.is_empty() && !matches!(self_ty.kind, TyKind::Path(_)) { + return None; + } + + for span in finder.upper { + suggestions.push((span, from.clone())); + } + for span in finder.lower { + suggestions.push((span, String::from("val"))); + } + + Some(suggestions) +} diff --git a/tests/ui/from_over_into.fixed b/tests/ui/from_over_into.fixed new file mode 100644 index 00000000000..e66dc43b047 --- /dev/null +++ b/tests/ui/from_over_into.fixed @@ -0,0 +1,62 @@ +// run-rustfix + +#![warn(clippy::from_over_into)] +#![allow(unused)] + +// this should throw an error +struct StringWrapper(String); + +impl From<String> for StringWrapper { + fn from(val: String) -> Self { + StringWrapper(val) + } +} + +struct SelfType(String); + +impl From<String> for SelfType { + fn from(val: String) -> Self { + SelfType(String::new()) + } +} + +#[derive(Default)] +struct X; + +impl X { + const FOO: &'static str = "a"; +} + +struct SelfKeywords; + +impl From<X> for SelfKeywords { + fn from(val: X) -> Self { + let _ = X::default(); + let _ = X::FOO; + let _: X = val; + + SelfKeywords + } +} + +struct ExplicitPaths(bool); + +impl core::convert::From<crate::ExplicitPaths> for bool { + fn from(mut val: crate::ExplicitPaths) -> Self { + let in_closure = || val.0; + + val.0 = false; + val.0 + } +} + +// this is fine +struct A(String); + +impl From<String> for A { + fn from(s: String) -> A { + A(s) + } +} + +fn main() {} diff --git a/tests/ui/from_over_into.rs b/tests/ui/from_over_into.rs index 292d0924fb1..74c7be6af79 100644 --- a/tests/ui/from_over_into.rs +++ b/tests/ui/from_over_into.rs @@ -1,4 +1,7 @@ +// run-rustfix + #![warn(clippy::from_over_into)] +#![allow(unused)] // this should throw an error struct StringWrapper(String); @@ -9,6 +12,44 @@ impl Into<StringWrapper> for String { } } +struct SelfType(String); + +impl Into<SelfType> for String { + fn into(self) -> SelfType { + SelfType(Self::new()) + } +} + +#[derive(Default)] +struct X; + +impl X { + const FOO: &'static str = "a"; +} + +struct SelfKeywords; + +impl Into<SelfKeywords> for X { + fn into(self) -> SelfKeywords { + let _ = Self::default(); + let _ = Self::FOO; + let _: Self = self; + + SelfKeywords + } +} + +struct ExplicitPaths(bool); + +impl core::convert::Into<bool> for crate::ExplicitPaths { + fn into(mut self) -> bool { + let in_closure = || self.0; + + self.0 = false; + self.0 + } +} + // this is fine struct A(String); diff --git a/tests/ui/from_over_into.stderr b/tests/ui/from_over_into.stderr index 469adadd219..6cf83e25807 100644 --- a/tests/ui/from_over_into.stderr +++ b/tests/ui/from_over_into.stderr @@ -1,11 +1,62 @@ error: an implementation of `From` is preferred since it gives you `Into<_>` for free where the reverse isn't true - --> $DIR/from_over_into.rs:6:1 + --> $DIR/from_over_into.rs:9:1 | LL | impl Into<StringWrapper> for String { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | - = help: consider to implement `From<std::string::String>` instead = note: `-D clippy::from-over-into` implied by `-D warnings` +help: replace the `Into` implentation with `From<std::string::String>` + | +LL ~ impl From<String> for StringWrapper { +LL ~ fn from(val: String) -> Self { +LL ~ StringWrapper(val) + | + +error: an implementation of `From` is preferred since it gives you `Into<_>` for free where the reverse isn't true + --> $DIR/from_over_into.rs:17:1 + | +LL | impl Into<SelfType> for String { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +help: replace the `Into` implentation with `From<std::string::String>` + | +LL ~ impl From<String> for SelfType { +LL ~ fn from(val: String) -> Self { +LL ~ SelfType(String::new()) + | + +error: an implementation of `From` is preferred since it gives you `Into<_>` for free where the reverse isn't true + --> $DIR/from_over_into.rs:32:1 + | +LL | impl Into<SelfKeywords> for X { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +help: replace the `Into` implentation with `From<X>` + | +LL ~ impl From<X> for SelfKeywords { +LL ~ fn from(val: X) -> Self { +LL ~ let _ = X::default(); +LL ~ let _ = X::FOO; +LL ~ let _: X = val; + | + +error: an implementation of `From` is preferred since it gives you `Into<_>` for free where the reverse isn't true + --> $DIR/from_over_into.rs:44:1 + | +LL | impl core::convert::Into<bool> for crate::ExplicitPaths { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | + = help: `impl From<Local> for Foreign` is allowed by the orphan rules, for more information see + https://doc.rust-lang.org/reference/items/implementations.html#trait-implementation-coherence +help: replace the `Into` implentation with `From<ExplicitPaths>` + | +LL ~ impl core::convert::From<crate::ExplicitPaths> for bool { +LL ~ fn from(mut val: crate::ExplicitPaths) -> Self { +LL ~ let in_closure = || val.0; +LL | +LL ~ val.0 = false; +LL ~ val.0 + | -error: aborting due to previous error +error: aborting due to 4 previous errors diff --git a/tests/ui/from_over_into_unfixable.rs b/tests/ui/from_over_into_unfixable.rs new file mode 100644 index 00000000000..3b280b7488a --- /dev/null +++ b/tests/ui/from_over_into_unfixable.rs @@ -0,0 +1,35 @@ +#![warn(clippy::from_over_into)] + +struct InMacro(String); + +macro_rules! in_macro { + ($e:ident) => { + $e + }; +} + +impl Into<InMacro> for String { + fn into(self) -> InMacro { + InMacro(in_macro!(self)) + } +} + +struct WeirdUpperSelf; + +impl Into<WeirdUpperSelf> for &'static [u8] { + fn into(self) -> WeirdUpperSelf { + let _ = Self::default(); + WeirdUpperSelf + } +} + +struct ContainsVal; + +impl Into<u8> for ContainsVal { + fn into(self) -> u8 { + let val = 1; + val + 1 + } +} + +fn main() {} diff --git a/tests/ui/from_over_into_unfixable.stderr b/tests/ui/from_over_into_unfixable.stderr new file mode 100644 index 00000000000..6f6ce351921 --- /dev/null +++ b/tests/ui/from_over_into_unfixable.stderr @@ -0,0 +1,29 @@ +error: an implementation of `From` is preferred since it gives you `Into<_>` for free where the reverse isn't true + --> $DIR/from_over_into_unfixable.rs:11:1 + | +LL | impl Into<InMacro> for String { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | + = help: replace the `Into` implentation with `From<std::string::String>` + = note: `-D clippy::from-over-into` implied by `-D warnings` + +error: an implementation of `From` is preferred since it gives you `Into<_>` for free where the reverse isn't true + --> $DIR/from_over_into_unfixable.rs:19:1 + | +LL | impl Into<WeirdUpperSelf> for &'static [u8] { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | + = help: replace the `Into` implentation with `From<&'static [u8]>` + +error: an implementation of `From` is preferred since it gives you `Into<_>` for free where the reverse isn't true + --> $DIR/from_over_into_unfixable.rs:28:1 + | +LL | impl Into<u8> for ContainsVal { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | + = help: `impl From<Local> for Foreign` is allowed by the orphan rules, for more information see + https://doc.rust-lang.org/reference/items/implementations.html#trait-implementation-coherence + = help: replace the `Into` implentation with `From<ContainsVal>` + +error: aborting due to 3 previous errors + |