Merge commit 'f51aade56f93175dde89177a92e3669ebd8e7592' into clippyup

5 files changed, 237 insertions, 6 deletions

diff --git a/clippy_lints/src/casts/as_underscore.rs b/clippy_lints/src/casts/as_underscore.rs
new file mode 100644
index 00000000000..56e894c6261
--- /dev/null
+++ b/clippy_lints/src/casts/as_underscore.rs
@@ -0,0 +1,25 @@
+use clippy_utils::diagnostics::span_lint_and_then;
+use rustc_errors::Applicability;
+use rustc_hir::{Expr, Ty, TyKind};
+use rustc_lint::LateContext;
+use rustc_middle::ty;
+
+use super::AS_UNDERSCORE;
+
+pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, ty: &'tcx Ty<'_>) {
+    if matches!(ty.kind, TyKind::Infer) {
+        span_lint_and_then(cx, AS_UNDERSCORE, expr.span, "using `as _` conversion", |diag| {
+            let ty_resolved = cx.typeck_results().expr_ty(expr);
+            if let ty::Error(_) = ty_resolved.kind() {
+                diag.help("consider giving the type explicitly");
+            } else {
+                diag.span_suggestion(
+                    ty.span,
+                    "consider giving the type explicitly",
+                    ty_resolved,
+                    Applicability::MachineApplicable,
+                );
+            }
+        });
+    }
+}
diff --git a/clippy_lints/src/casts/borrow_as_ptr.rs b/clippy_lints/src/casts/borrow_as_ptr.rs
new file mode 100644
index 00000000000..6e1f8cd64f0
--- /dev/null
+++ b/clippy_lints/src/casts/borrow_as_ptr.rs
@@ -0,0 +1,37 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::is_no_std_crate;
+use clippy_utils::source::snippet_with_context;
+use rustc_errors::Applicability;
+use rustc_hir::{BorrowKind, Expr, ExprKind, Mutability, Ty, TyKind};
+use rustc_lint::LateContext;
+
+use super::BORROW_AS_PTR;
+
+pub(super) fn check<'tcx>(
+    cx: &LateContext<'tcx>,
+    expr: &'tcx Expr<'_>,
+    cast_expr: &'tcx Expr<'_>,
+    cast_to: &'tcx Ty<'_>,
+) {
+    if matches!(cast_to.kind, TyKind::Ptr(_))
+        && let ExprKind::AddrOf(BorrowKind::Ref, mutability, e) = cast_expr.kind
+    {
+        let core_or_std = if is_no_std_crate(cx) { "core" } else { "std" };
+        let macro_name = match mutability {
+            Mutability::Not => "addr_of",
+            Mutability::Mut => "addr_of_mut",
+        };
+        let mut app = Applicability::MachineApplicable;
+        let snip = snippet_with_context(cx, e.span, cast_expr.span.ctxt(), "..", &mut app).0;
+
+        span_lint_and_sugg(
+            cx,
+            BORROW_AS_PTR,
+            expr.span,
+            "borrow as raw pointer",
+            "try",
+            format!("{}::ptr::{}!({})", core_or_std, macro_name, snip),
+            Applicability::MachineApplicable,
+        );
+    }
+}
diff --git a/clippy_lints/src/casts/cast_slice_from_raw_parts.rs b/clippy_lints/src/casts/cast_slice_from_raw_parts.rs
new file mode 100644
index 00000000000..284ef165998
--- /dev/null
+++ b/clippy_lints/src/casts/cast_slice_from_raw_parts.rs
@@ -0,0 +1,63 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::snippet_with_applicability;
+use clippy_utils::{match_def_path, meets_msrv, msrvs, paths};
+use if_chain::if_chain;
+use rustc_errors::Applicability;
+use rustc_hir::{def_id::DefId, Expr, ExprKind};
+use rustc_lint::LateContext;
+use rustc_middle::ty::{self, Ty};
+use rustc_semver::RustcVersion;
+
+use super::CAST_SLICE_FROM_RAW_PARTS;
+
+enum RawPartsKind {
+    Immutable,
+    Mutable,
+}
+
+fn raw_parts_kind(cx: &LateContext<'_>, did: DefId) -> Option<RawPartsKind> {
+    if match_def_path(cx, did, &paths::SLICE_FROM_RAW_PARTS) {
+        Some(RawPartsKind::Immutable)
+    } else if match_def_path(cx, did, &paths::SLICE_FROM_RAW_PARTS_MUT) {
+        Some(RawPartsKind::Mutable)
+    } else {
+        None
+    }
+}
+
+pub(super) fn check(
+    cx: &LateContext<'_>,
+    expr: &Expr<'_>,
+    cast_expr: &Expr<'_>,
+    cast_to: Ty<'_>,
+    msrv: Option<RustcVersion>,
+) {
+    if_chain! {
+        if meets_msrv(msrv, msrvs::PTR_SLICE_RAW_PARTS);
+        if let ty::RawPtr(ptrty) = cast_to.kind();
+        if let ty::Slice(_) = ptrty.ty.kind();
+        if let ExprKind::Call(fun, [ptr_arg, len_arg]) = cast_expr.peel_blocks().kind;
+        if let ExprKind::Path(ref qpath) = fun.kind;
+        if let Some(fun_def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id();
+        if let Some(rpk) = raw_parts_kind(cx, fun_def_id);
+        then {
+            let func = match rpk {
+                RawPartsKind::Immutable => "from_raw_parts",
+                RawPartsKind::Mutable => "from_raw_parts_mut"
+            };
+            let span = expr.span;
+            let mut applicability = Applicability::MachineApplicable;
+            let ptr = snippet_with_applicability(cx, ptr_arg.span, "ptr", &mut applicability);
+            let len = snippet_with_applicability(cx, len_arg.span, "len", &mut applicability);
+            span_lint_and_sugg(
+                cx,
+                CAST_SLICE_FROM_RAW_PARTS,
+                span,
+                &format!("casting the result of `{func}` to {cast_to}"),
+                "replace with",
+                format!("core::ptr::slice_{func}({ptr}, {len})"),
+                applicability
+            );
+        }
+    }
+}
diff --git a/clippy_lints/src/casts/mod.rs b/clippy_lints/src/casts/mod.rs
index af3798a0cc8..cc5d346b954 100644
--- a/clippy_lints/src/casts/mod.rs
+++ b/clippy_lints/src/casts/mod.rs
@@ -1,3 +1,5 @@
+mod as_underscore;
+mod borrow_as_ptr;
 mod cast_abs_to_unsigned;
 mod cast_enum_constructor;
 mod cast_lossless;
@@ -8,6 +10,7 @@ mod cast_ptr_alignment;
 mod cast_ref_to_mut;
 mod cast_sign_loss;
 mod cast_slice_different_sizes;
+mod cast_slice_from_raw_parts;
 mod char_lit_as_u8;
 mod fn_to_numeric_cast;
 mod fn_to_numeric_cast_any;
@@ -16,7 +19,7 @@ mod ptr_as_ptr;
 mod unnecessary_cast;
 mod utils;
 
-use clippy_utils::is_hir_ty_cfg_dependant;
+use clippy_utils::{is_hir_ty_cfg_dependant, meets_msrv, msrvs};
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::lint::in_external_macro;
@@ -506,6 +509,93 @@ declare_clippy_lint! {
     "casting the result of `abs()` to an unsigned integer can panic"
 }
 
+declare_clippy_lint! {
+    /// ### What it does
+    /// Check for the usage of `as _` conversion using inferred type.
+    ///
+    /// ### Why is this bad?
+    /// The conversion might include lossy conversion and dangerous cast that might go
+    /// undetected due to the type being inferred.
+    ///
+    /// The lint is allowed by default as using `_` is less wordy than always specifying the type.
+    ///
+    /// ### Example
+    /// ```rust
+    /// fn foo(n: usize) {}
+    /// let n: u16 = 256;
+    /// foo(n as _);
+    /// ```
+    /// Use instead:
+    /// ```rust
+    /// fn foo(n: usize) {}
+    /// let n: u16 = 256;
+    /// foo(n as usize);
+    /// ```
+    #[clippy::version = "1.63.0"]
+    pub AS_UNDERSCORE,
+    restriction,
+    "detects `as _` conversion"
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for the usage of `&expr as *const T` or
+    /// `&mut expr as *mut T`, and suggest using `ptr::addr_of` or
+    /// `ptr::addr_of_mut` instead.
+    ///
+    /// ### Why is this bad?
+    /// This would improve readability and avoid creating a reference
+    /// that points to an uninitialized value or unaligned place.
+    /// Read the `ptr::addr_of` docs for more information.
+    ///
+    /// ### Example
+    /// ```rust
+    /// let val = 1;
+    /// let p = &val as *const i32;
+    ///
+    /// let mut val_mut = 1;
+    /// let p_mut = &mut val_mut as *mut i32;
+    /// ```
+    /// Use instead:
+    /// ```rust
+    /// let val = 1;
+    /// let p = std::ptr::addr_of!(val);
+    ///
+    /// let mut val_mut = 1;
+    /// let p_mut = std::ptr::addr_of_mut!(val_mut);
+    /// ```
+    #[clippy::version = "1.60.0"]
+    pub BORROW_AS_PTR,
+    pedantic,
+    "borrowing just to cast to a raw pointer"
+}
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for a raw slice being cast to a slice pointer
+    ///
+    /// ### Why is this bad?
+    /// This can result in multiple `&mut` references to the same location when only a pointer is
+    /// required.
+    /// `ptr::slice_from_raw_parts` is a safe alternative that doesn't require
+    /// the same [safety requirements] to be upheld.
+    ///
+    /// ### Example
+    /// ```rust,ignore
+    /// let _: *const [u8] = std::slice::from_raw_parts(ptr, len) as *const _;
+    /// let _: *mut [u8] = std::slice::from_raw_parts_mut(ptr, len) as *mut _;
+    /// ```
+    /// Use instead:
+    /// ```rust,ignore
+    /// let _: *const [u8] = std::ptr::slice_from_raw_parts(ptr, len);
+    /// let _: *mut [u8] = std::ptr::slice_from_raw_parts_mut(ptr, len);
+    /// ```
+    /// [safety requirements]: https://doc.rust-lang.org/std/slice/fn.from_raw_parts.html#safety
+    #[clippy::version = "1.64.0"]
+    pub CAST_SLICE_FROM_RAW_PARTS,
+    suspicious,
+    "casting a slice created from a pointer and length to a slice pointer"
+}
+
 pub struct Casts {
     msrv: Option<RustcVersion>,
 }
@@ -534,7 +624,10 @@ impl_lint_pass!(Casts => [
     PTR_AS_PTR,
     CAST_ENUM_TRUNCATION,
     CAST_ENUM_CONSTRUCTOR,
-    CAST_ABS_TO_UNSIGNED
+    CAST_ABS_TO_UNSIGNED,
+    AS_UNDERSCORE,
+    BORROW_AS_PTR,
+    CAST_SLICE_FROM_RAW_PARTS
 ]);
 
 impl<'tcx> LateLintPass<'tcx> for Casts {
@@ -547,8 +640,8 @@ impl<'tcx> LateLintPass<'tcx> for Casts {
             return;
         }
 
-        if let ExprKind::Cast(cast_expr, cast_to) = expr.kind {
-            if is_hir_ty_cfg_dependant(cx, cast_to) {
+        if let ExprKind::Cast(cast_expr, cast_to_hir) = expr.kind {
+            if is_hir_ty_cfg_dependant(cx, cast_to_hir) {
                 return;
             }
             let (cast_from, cast_to) = (
@@ -559,7 +652,7 @@ impl<'tcx> LateLintPass<'tcx> for Casts {
             if unnecessary_cast::check(cx, expr, cast_expr, cast_from, cast_to) {
                 return;
             }
-
+            cast_slice_from_raw_parts::check(cx, expr, cast_expr, cast_to, self.msrv);
             fn_to_numeric_cast_any::check(cx, expr, cast_expr, cast_from, cast_to);
             fn_to_numeric_cast::check(cx, expr, cast_expr, cast_from, cast_to);
             fn_to_numeric_cast_with_truncation::check(cx, expr, cast_expr, cast_from, cast_to);
@@ -575,6 +668,12 @@ impl<'tcx> LateLintPass<'tcx> for Casts {
                 cast_lossless::check(cx, expr, cast_expr, cast_from, cast_to, self.msrv);
                 cast_enum_constructor::check(cx, expr, cast_expr, cast_from);
             }
+
+            as_underscore::check(cx, expr, cast_to_hir);
+
+            if meets_msrv(self.msrv, msrvs::BORROW_AS_PTR) {
+                borrow_as_ptr::check(cx, expr, cast_expr, cast_to_hir);
+            }
         }
 
         cast_ref_to_mut::check(cx, expr);
diff --git a/clippy_lints/src/casts/unnecessary_cast.rs b/clippy_lints/src/casts/unnecessary_cast.rs
index fff7da8e33f..19d2e6e1d12 100644
--- a/clippy_lints/src/casts/unnecessary_cast.rs
+++ b/clippy_lints/src/casts/unnecessary_cast.rs
@@ -90,13 +90,20 @@ pub(super) fn check<'tcx>(
 
 fn lint_unnecessary_cast(cx: &LateContext<'_>, expr: &Expr<'_>, literal_str: &str, cast_from: Ty<'_>, cast_to: Ty<'_>) {
     let literal_kind_name = if cast_from.is_integral() { "integer" } else { "float" };
+    let replaced_literal;
+    let matchless = if literal_str.contains(['(', ')']) {
+        replaced_literal = literal_str.replace(['(', ')'], "");
+        &replaced_literal
+    } else {
+        literal_str
+    };
     span_lint_and_sugg(
         cx,
         UNNECESSARY_CAST,
         expr.span,
         &format!("casting {} literal to `{}` is unnecessary", literal_kind_name, cast_to),
         "try",
-        format!("{}_{}", literal_str.trim_end_matches('.'), cast_to),
+        format!("{}_{}", matchless.trim_end_matches('.'), cast_to),
         Applicability::MachineApplicable,
     );
 }