diff options
| -rw-r--r-- | clippy_lints/src/dereference.rs | 37 | ||||
| -rw-r--r-- | clippy_utils/src/lib.rs | 11 | ||||
| -rw-r--r-- | tests/ui/explicit_auto_deref.fixed | 36 | ||||
| -rw-r--r-- | tests/ui/explicit_auto_deref.rs | 36 | ||||
| -rw-r--r-- | tests/ui/explicit_auto_deref.stderr | 8 |
5 files changed, 116 insertions, 12 deletions
diff --git a/clippy_lints/src/dereference.rs b/clippy_lints/src/dereference.rs index a115f8d0631..253f9959e13 100644 --- a/clippy_lints/src/dereference.rs +++ b/clippy_lints/src/dereference.rs @@ -3,7 +3,8 @@ use clippy_utils::source::{snippet_with_applicability, snippet_with_context}; use clippy_utils::sugg::has_enclosing_paren; use clippy_utils::ty::{implements_trait, is_manually_drop, peel_mid_ty_refs}; use clippy_utils::{ - expr_use_ctxt, get_parent_expr, is_block_like, is_lint_allowed, path_to_local, DefinedTy, ExprUseNode, + expr_use_ctxt, get_parent_expr, is_block_like, is_lint_allowed, path_to_local, peel_middle_ty_refs, DefinedTy, + ExprUseNode, }; use core::mem; use rustc_ast::util::parser::{PREC_PREFIX, PREC_UNAMBIGUOUS}; @@ -175,6 +176,7 @@ struct StateData<'tcx> { adjusted_ty: Ty<'tcx>, } +#[derive(Debug)] struct DerefedBorrow { count: usize, msg: &'static str, @@ -182,6 +184,7 @@ struct DerefedBorrow { for_field_access: Option<Symbol>, } +#[derive(Debug)] enum State { // Any number of deref method calls. DerefMethod { @@ -744,7 +747,7 @@ fn in_postfix_position<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'tcx>) -> boo } } -#[derive(Clone, Copy)] +#[derive(Clone, Copy, Debug)] enum TyCoercionStability { Deref, Reborrow, @@ -1042,16 +1045,28 @@ fn report<'tcx>( return; } - let (prefix, precedence) = if let Some(mutability) = mutability - && !typeck.expr_ty(expr).is_ref() + let ty = typeck.expr_ty(expr); + + // `&&[T; N]`, or `&&..&[T; N]` (src) cannot coerce to `&[T]` (dst). + if let ty::Ref(_, dst, _) = data.adjusted_ty.kind() + && dst.is_slice() { - let prefix = match mutability { - Mutability::Not => "&", - Mutability::Mut => "&mut ", - }; - (prefix, PREC_PREFIX) - } else { - ("", 0) + let (src, n_src_refs) = peel_middle_ty_refs(ty); + if n_src_refs >= 2 && src.is_array() { + return; + } + } + + let (prefix, precedence) = match mutability { + Some(mutability) if !ty.is_ref() => { + let prefix = match mutability { + Mutability::Not => "&", + Mutability::Mut => "&mut ", + }; + (prefix, PREC_PREFIX) + }, + None if !ty.is_ref() && data.adjusted_ty.is_ref() => ("&", 0), + _ => ("", 0), }; span_lint_hir_and_then( cx, diff --git a/clippy_utils/src/lib.rs b/clippy_utils/src/lib.rs index 8a6750c8997..45a31fe442b 100644 --- a/clippy_utils/src/lib.rs +++ b/clippy_utils/src/lib.rs @@ -2492,6 +2492,17 @@ pub fn peel_hir_ty_refs<'a>(mut ty: &'a hir::Ty<'a>) -> (&'a hir::Ty<'a>, usize) } } +/// Peels off all references on the type. Returns the underlying type and the number of references +/// removed. +pub fn peel_middle_ty_refs(mut ty: Ty<'_>) -> (Ty<'_>, usize) { + let mut count = 0; + while let rustc_ty::Ref(_, dest_ty, _) = ty.kind() { + ty = *dest_ty; + count += 1; + } + (ty, count) +} + /// Removes `AddrOf` operators (`&`) or deref operators (`*`), but only if a reference type is /// dereferenced. An overloaded deref such as `Vec` to slice would not be removed. pub fn peel_ref_operators<'hir>(cx: &LateContext<'_>, mut expr: &'hir Expr<'hir>) -> &'hir Expr<'hir> { diff --git a/tests/ui/explicit_auto_deref.fixed b/tests/ui/explicit_auto_deref.fixed index e6ca4bb66cc..255b2c5a220 100644 --- a/tests/ui/explicit_auto_deref.fixed +++ b/tests/ui/explicit_auto_deref.fixed @@ -345,3 +345,39 @@ fn main() { let _ = &mut ({ *x.u }).x; } } + +mod issue_12969 { + use std::ops::Deref; + + struct Wrapper<T>(T); + + impl<T> Deref for Wrapper<T> { + type Target = T; + + fn deref(&self) -> &T { + &self.0 + } + } + + fn foo(_bar: &str) {} + + fn bar() { + let wrapped_bar = Wrapper(""); + + foo(&wrapped_bar); + } +} + +mod issue_9841 { + fn takes_array_ref<T, const N: usize>(array: &&[T; N]) { + takes_slice(*array) + } + + fn takes_array_ref_ref<T, const N: usize>(array: &&&[T; N]) { + takes_slice(**array) + } + + fn takes_slice<T>(slice: &[T]) { + todo!() + } +} diff --git a/tests/ui/explicit_auto_deref.rs b/tests/ui/explicit_auto_deref.rs index 7531e1f87b7..99906999f01 100644 --- a/tests/ui/explicit_auto_deref.rs +++ b/tests/ui/explicit_auto_deref.rs @@ -345,3 +345,39 @@ fn main() { let _ = &mut ({ *x.u }).x; } } + +mod issue_12969 { + use std::ops::Deref; + + struct Wrapper<T>(T); + + impl<T> Deref for Wrapper<T> { + type Target = T; + + fn deref(&self) -> &T { + &self.0 + } + } + + fn foo(_bar: &str) {} + + fn bar() { + let wrapped_bar = Wrapper(""); + + foo(&*wrapped_bar); + } +} + +mod issue_9841 { + fn takes_array_ref<T, const N: usize>(array: &&[T; N]) { + takes_slice(*array) + } + + fn takes_array_ref_ref<T, const N: usize>(array: &&&[T; N]) { + takes_slice(**array) + } + + fn takes_slice<T>(slice: &[T]) { + todo!() + } +} diff --git a/tests/ui/explicit_auto_deref.stderr b/tests/ui/explicit_auto_deref.stderr index 56a183de348..53784934f63 100644 --- a/tests/ui/explicit_auto_deref.stderr +++ b/tests/ui/explicit_auto_deref.stderr @@ -271,5 +271,11 @@ error: deref which would be done by auto-deref LL | let _ = &mut (*{ x.u }).x; | ^^^^^^^^^^ help: try: `{ x.u }` -error: aborting due to 45 previous errors +error: deref which would be done by auto-deref + --> tests/ui/explicit_auto_deref.rs:367:13 + | +LL | foo(&*wrapped_bar); + | ^^^^^^^^^^^^^ help: try: `&wrapped_bar` + +error: aborting due to 46 previous errors |