diff options
| -rw-r--r-- | clippy_lints/src/methods/mod.rs | 58 | ||||
| -rw-r--r-- | tests/ui/new_ret_no_self.rs | 130 | ||||
| -rw-r--r-- | tests/ui/new_ret_no_self.stderr | 30 |
3 files changed, 212 insertions, 6 deletions
diff --git a/clippy_lints/src/methods/mod.rs b/clippy_lints/src/methods/mod.rs index 1ef54d285f6..8e91cbb3cdf 100644 --- a/clippy_lints/src/methods/mod.rs +++ b/clippy_lints/src/methods/mod.rs @@ -15,6 +15,7 @@ use rustc_ast::ast; use rustc_errors::Applicability; use rustc_hir as hir; use rustc_hir::intravisit::{self, Visitor}; +use rustc_hir::{FnRetTy, FnSig, TraitItem, TraitItemKind}; use rustc_lint::{LateContext, LateLintPass, Lint, LintContext}; use rustc_middle::hir::map::Map; use rustc_middle::lint::in_external_macro; @@ -28,11 +29,11 @@ use crate::consts::{constant, Constant}; use crate::utils::usage::mutated_variables; use crate::utils::{ get_arg_name, get_parent_expr, get_trait_def_id, has_iter_method, higher, implements_trait, in_macro, is_copy, - is_ctor_or_promotable_const_function, is_expn_of, is_type_diagnostic_item, iter_input_pats, last_path_segment, - match_def_path, match_qpath, match_trait_method, match_type, match_var, method_calls, method_chain_args, paths, - remove_blocks, return_ty, single_segment_path, snippet, snippet_with_applicability, snippet_with_macro_callsite, - span_lint, span_lint_and_help, span_lint_and_note, span_lint_and_sugg, span_lint_and_then, sugg, walk_ptrs_ty, - walk_ptrs_ty_depth, SpanlessEq, + is_ctor_or_promotable_const_function, is_expn_of, is_self_ty, is_type_diagnostic_item, iter_input_pats, + last_path_segment, match_def_path, match_qpath, match_trait_method, match_type, match_var, method_calls, + method_chain_args, paths, remove_blocks, return_ty, single_segment_path, snippet, snippet_with_applicability, + snippet_with_macro_callsite, span_lint, span_lint_and_help, span_lint_and_note, span_lint_and_sugg, + span_lint_and_then, sugg, walk_ptrs_ty, walk_ptrs_ty_depth, SpanlessEq, }; declare_clippy_lint! { @@ -1631,6 +1632,11 @@ impl<'tcx> LateLintPass<'tcx> for Methods { } } + // if this impl block implements a trait, lint in trait definition instead + if let hir::ItemKind::Impl { of_trait: Some(_), .. } = item.kind { + return; + } + if let hir::ImplItemKind::Fn(_, _) = impl_item.kind { let ret_ty = return_ty(cx, impl_item.hir_id); @@ -1670,6 +1676,48 @@ impl<'tcx> LateLintPass<'tcx> for Methods { } } } + + fn check_trait_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx TraitItem<'_>) { + if_chain! { + if !in_external_macro(cx.tcx.sess, item.span); + if !item.span.from_expansion(); + if item.ident.name == sym!(new); + if let TraitItemKind::Fn(FnSig { decl, .. }, _) = &item.kind; + if let FnRetTy::Return(ret_ty) = &decl.output; + + then { + let mut visitor = HasSelfVisitor { has_self_ty: false }; + visitor.visit_ty(ret_ty); + if !visitor.has_self_ty { + span_lint( + cx, + NEW_RET_NO_SELF, + item.span, + "methods called `new` usually return `Self`", + ); + } + } + } + } +} + +struct HasSelfVisitor { + pub has_self_ty: bool, +} + +impl<'tcx> intravisit::Visitor<'tcx> for HasSelfVisitor { + type Map = Map<'tcx>; + + fn visit_ty(&mut self, ty: &'tcx hir::Ty<'_>) { + if is_self_ty(ty) { + self.has_self_ty = true; + } else { + intravisit::walk_ty(self, ty); + } + } + fn nested_visit_map(&mut self) -> intravisit::NestedVisitorMap<Self::Map> { + intravisit::NestedVisitorMap::None + } } /// Checks for the `OR_FUN_CALL` lint. diff --git a/tests/ui/new_ret_no_self.rs b/tests/ui/new_ret_no_self.rs index 2c2d1e27589..e98360ea691 100644 --- a/tests/ui/new_ret_no_self.rs +++ b/tests/ui/new_ret_no_self.rs @@ -210,3 +210,133 @@ impl<'a> WithLifetime<'a> { unimplemented!(); } } + +mod issue5435 { + struct V; + + pub trait TraitRetSelf { + // should not trigger lint + fn new() -> Self; + } + + pub trait TraitRet { + // should trigger lint as we are in trait definition + fn new() -> String; + } + pub struct StructRet; + impl TraitRet for StructRet { + // should not trigger lint as we are in the impl block + fn new() -> String { + unimplemented!(); + } + } + + pub trait TraitRet2 { + // should trigger lint + fn new(_: String) -> String; + } + + trait TupleReturnerOk { + // should not trigger lint + fn new() -> (Self, u32) + where + Self: Sized, + { + unimplemented!(); + } + } + + trait TupleReturnerOk2 { + // should not trigger lint (it doesn't matter which element in the tuple is Self) + fn new() -> (u32, Self) + where + Self: Sized, + { + unimplemented!(); + } + } + + trait TupleReturnerOk3 { + // should not trigger lint (tuple can contain multiple Self) + fn new() -> (Self, Self) + where + Self: Sized, + { + unimplemented!(); + } + } + + trait TupleReturnerBad { + // should trigger lint + fn new() -> (u32, u32) { + unimplemented!(); + } + } + + trait MutPointerReturnerOk { + // should not trigger lint + fn new() -> *mut Self + where + Self: Sized, + { + unimplemented!(); + } + } + + trait MutPointerReturnerOk2 { + // should not trigger lint + fn new() -> *const Self + where + Self: Sized, + { + unimplemented!(); + } + } + + trait MutPointerReturnerBad { + // should trigger lint + fn new() -> *mut V { + unimplemented!(); + } + } + + trait GenericReturnerOk { + // should not trigger lint + fn new() -> Option<Self> + where + Self: Sized, + { + unimplemented!(); + } + } + + trait NestedReturnerOk { + // should not trigger lint + fn new() -> (Option<Self>, u32) + where + Self: Sized, + { + unimplemented!(); + } + } + + trait NestedReturnerOk2 { + // should not trigger lint + fn new() -> ((Self, u32), u32) + where + Self: Sized, + { + unimplemented!(); + } + } + + trait NestedReturnerOk3 { + // should not trigger lint + fn new() -> Option<(Self, u32)> + where + Self: Sized, + { + unimplemented!(); + } + } +} diff --git a/tests/ui/new_ret_no_self.stderr b/tests/ui/new_ret_no_self.stderr index dd5a24bcbe7..8217bc6187f 100644 --- a/tests/ui/new_ret_no_self.stderr +++ b/tests/ui/new_ret_no_self.stderr @@ -48,5 +48,33 @@ LL | | unimplemented!(); LL | | } | |_____^ -error: aborting due to 6 previous errors +error: methods called `new` usually return `Self` + --> $DIR/new_ret_no_self.rs:224:9 + | +LL | fn new() -> String; + | ^^^^^^^^^^^^^^^^^^^ + +error: methods called `new` usually return `Self` + --> $DIR/new_ret_no_self.rs:236:9 + | +LL | fn new(_: String) -> String; + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +error: methods called `new` usually return `Self` + --> $DIR/new_ret_no_self.rs:271:9 + | +LL | / fn new() -> (u32, u32) { +LL | | unimplemented!(); +LL | | } + | |_________^ + +error: methods called `new` usually return `Self` + --> $DIR/new_ret_no_self.rs:298:9 + | +LL | / fn new() -> *mut V { +LL | | unimplemented!(); +LL | | } + | |_________^ + +error: aborting due to 10 previous errors |