src/tools/clippy/clippy_lints/src/misc.rs - third_party/rust - Git at Google

 use clippy_utils::diagnostics::{span_lint, span_lint_and_sugg, span_lint_hir_and_then};
 use clippy_utils::source::{snippet, snippet_opt, snippet_with_context};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::intravisit::FnKind;
 use rustc_hir::{
     self as hir, def, BinOpKind, BindingAnnotation, Body, ByRef, Expr, ExprKind, FnDecl, Mutability, PatKind, Stmt,
     StmtKind, TyKind,
 };
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::lint::in_external_macro;
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::def_id::LocalDefId;
 use rustc_span::hygiene::DesugaringKind;
 use rustc_span::source_map::{ExpnKind, Span};

 use clippy_utils::sugg::Sugg;
 use clippy_utils::{
     get_parent_expr, in_constant, is_integer_literal, is_lint_allowed, is_no_std_crate, iter_input_pats,
     last_path_segment, SpanlessEq,
 };

 use crate::ref_patterns::REF_PATTERNS;

 declare_clippy_lint! {
     /// ### What it does
     /// Checks for function arguments and let bindings denoted as
     /// `ref`.
     ///
     /// ### Why is this bad?
     /// The `ref` declaration makes the function take an owned
     /// value, but turns the argument into a reference (which means that the value
     /// is destroyed when exiting the function). This adds not much value: either
     /// take a reference type, or take an owned value and create references in the
     /// body.
     ///
     /// For let bindings, `let x = &foo;` is preferred over `let ref x = foo`. The
     /// type of `x` is more obvious with the former.
     ///
     /// ### Known problems
     /// If the argument is dereferenced within the function,
     /// removing the `ref` will lead to errors. This can be fixed by removing the
     /// dereferences, e.g., changing `*x` to `x` within the function.
     ///
     /// ### Example
     /// ```rust
     /// fn foo(ref _x: u8) {}
     /// ```
     ///
     /// Use instead:
     /// ```rust
     /// fn foo(_x: &u8) {}
     /// ```
     #[clippy::version = "pre 1.29.0"]
     pub TOPLEVEL_REF_ARG,
     style,
     "an entire binding declared as `ref`, in a function argument or a `let` statement"
 }
 declare_clippy_lint! {
     /// ### What it does
     /// Checks for the use of bindings with a single leading
     /// underscore.
     ///
     /// ### Why is this bad?
     /// A single leading underscore is usually used to indicate
     /// that a binding will not be used. Using such a binding breaks this
     /// expectation.
     ///
     /// ### Known problems
     /// The lint does not work properly with desugaring and
     /// macro, it has been allowed in the mean time.
     ///
     /// ### Example
     /// ```rust
     /// let _x = 0;
     /// let y = _x + 1; // Here we are using `_x`, even though it has a leading
     ///                 // underscore. We should rename `_x` to `x`
     /// ```
     #[clippy::version = "pre 1.29.0"]
     pub USED_UNDERSCORE_BINDING,
     pedantic,
     "using a binding which is prefixed with an underscore"
 }

 declare_clippy_lint! {
     /// ### What it does
     /// Checks for the use of short circuit boolean conditions as
     /// a
     /// statement.
     ///
     /// ### Why is this bad?
     /// Using a short circuit boolean condition as a statement
     /// may hide the fact that the second part is executed or not depending on the
     /// outcome of the first part.
     ///
     /// ### Example
     /// ```rust,ignore
     /// f() && g(); // We should write `if f() { g(); }`.
     /// ```
     #[clippy::version = "pre 1.29.0"]
     pub SHORT_CIRCUIT_STATEMENT,
     complexity,
     "using a short circuit boolean condition as a statement"
 }

 declare_clippy_lint! {
     /// ### What it does
     /// Catch casts from `0` to some pointer type
     ///
     /// ### Why is this bad?
     /// This generally means `null` and is better expressed as
     /// {`std`, `core`}`::ptr::`{`null`, `null_mut`}.
     ///
     /// ### Example
     /// ```rust
     /// let a = 0 as *const u32;
     /// ```
     ///
     /// Use instead:
     /// ```rust
     /// let a = std::ptr::null::<u32>();
     /// ```
     #[clippy::version = "pre 1.29.0"]
     pub ZERO_PTR,
     style,
     "using `0 as *{const, mut} T`"
 }

 pub struct LintPass {
     std_or_core: &'static str,
 }
 impl Default for LintPass {
     fn default() -> Self {
         Self { std_or_core: "std" }
     }
 }
 impl_lint_pass!(LintPass => [
     TOPLEVEL_REF_ARG,
     USED_UNDERSCORE_BINDING,
     SHORT_CIRCUIT_STATEMENT,
     ZERO_PTR,
 ]);

 impl<'tcx> LateLintPass<'tcx> for LintPass {
     fn check_crate(&mut self, cx: &LateContext<'_>) {
         if is_no_std_crate(cx) {
             self.std_or_core = "core";
         }
     }

     fn check_fn(
         &mut self,
         cx: &LateContext<'tcx>,
         k: FnKind<'tcx>,
         decl: &'tcx FnDecl<'_>,
         body: &'tcx Body<'_>,
         span: Span,
         _: LocalDefId,
     ) {
         if let FnKind::Closure = k {
             // Does not apply to closures
             return;
         }
         if in_external_macro(cx.tcx.sess, span) {
             return;
         }
         for arg in iter_input_pats(decl, body) {
             // Do not emit if clippy::ref_patterns is not allowed to avoid having two lints for the same issue.
             if !is_lint_allowed(cx, REF_PATTERNS, arg.pat.hir_id) {
                 return;
             }
             if let PatKind::Binding(BindingAnnotation(ByRef::Yes, _), ..) = arg.pat.kind {
                 span_lint(
                     cx,
                     TOPLEVEL_REF_ARG,
                     arg.pat.span,
                     "`ref` directly on a function argument is ignored. \
                     Consider using a reference type instead",
                 );
             }
         }
     }

     fn check_stmt(&mut self, cx: &LateContext<'tcx>, stmt: &'tcx Stmt<'_>) {
         if_chain! {
             if !in_external_macro(cx.tcx.sess, stmt.span);
             if let StmtKind::Local(local) = stmt.kind;
             if let PatKind::Binding(BindingAnnotation(ByRef::Yes, mutabl), .., name, None) = local.pat.kind;
             if let Some(init) = local.init;
             // Do not emit if clippy::ref_patterns is not allowed to avoid having two lints for the same issue.
             if is_lint_allowed(cx, REF_PATTERNS, local.pat.hir_id);
             then {
                 let ctxt = local.span.ctxt();
                 let mut app = Applicability::MachineApplicable;
                 let sugg_init = Sugg::hir_with_context(cx, init, ctxt, "..", &mut app);
                 let (mutopt, initref) = if mutabl == Mutability::Mut {
                     ("mut ", sugg_init.mut_addr())
                 } else {
                     ("", sugg_init.addr())
                 };
                 let tyopt = if let Some(ty) = local.ty {
                     let ty_snip = snippet_with_context(cx, ty.span, ctxt, "_", &mut app).0;
                     format!(": &{mutopt}{ty_snip}")
                 } else {
                     String::new()
                 };
                 span_lint_hir_and_then(
                     cx,
                     TOPLEVEL_REF_ARG,
                     init.hir_id,
                     local.pat.span,
                     "`ref` on an entire `let` pattern is discouraged, take a reference with `&` instead",
                     |diag| {
                         diag.span_suggestion(
                             stmt.span,
                             "try",
                             format!(
                                 "let {name}{tyopt} = {initref};",
                                 name=snippet(cx, name.span, ".."),
                             ),
                             app,
                         );
                     }
                 );
             }
         };
         if_chain! {
             if let StmtKind::Semi(expr) = stmt.kind;
             if let ExprKind::Binary(ref binop, a, b) = expr.kind;
             if binop.node == BinOpKind::And || binop.node == BinOpKind::Or;
             if let Some(sugg) = Sugg::hir_opt(cx, a);
             then {
                 span_lint_hir_and_then(
                     cx,
                     SHORT_CIRCUIT_STATEMENT,
                     expr.hir_id,
                     stmt.span,
                     "boolean short circuit operator in statement may be clearer using an explicit test",
                     |diag| {
                         let sugg = if binop.node == BinOpKind::Or { !sugg } else { sugg };
                         diag.span_suggestion(
                             stmt.span,
                             "replace it with",
                             format!(
                                 "if {sugg} {{ {}; }}",
                                 &snippet(cx, b.span, ".."),
                             ),
                             Applicability::MachineApplicable, // snippet
                         );
                     });
             }
         };
     }

     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
         if let ExprKind::Cast(e, ty) = expr.kind {
             self.check_cast(cx, expr.span, e, ty);
             return;
         }
         if in_attributes_expansion(expr) || expr.span.is_desugaring(DesugaringKind::Await) {
             // Don't lint things expanded by #[derive(...)], etc or `await` desugaring
             return;
         }
         let sym;
         let binding = match expr.kind {
             ExprKind::Path(ref qpath) if !matches!(qpath, hir::QPath::LangItem(..)) => {
                 let binding = last_path_segment(qpath).ident.as_str();
                 if binding.starts_with('_') &&
                     !binding.starts_with("__") &&
                     binding != "_result" && // FIXME: #944
                     is_used(cx, expr) &&
                     // don't lint if the declaration is in a macro
                     non_macro_local(cx, cx.qpath_res(qpath, expr.hir_id))
                 {
                     Some(binding)
                 } else {
                     None
                 }
             },
             ExprKind::Field(_, ident) => {
                 sym = ident.name;
                 let name = sym.as_str();
                 if name.starts_with('_') && !name.starts_with("__") {
                     Some(name)
                 } else {
                     None
                 }
             },
             _ => None,
         };
         if let Some(binding) = binding {
             span_lint(
                 cx,
                 USED_UNDERSCORE_BINDING,
                 expr.span,
                 &format!(
                     "used binding `{binding}` which is prefixed with an underscore. A leading \
                      underscore signals that a binding will not be used"
                 ),
             );
         }
     }
 }

 /// Heuristic to see if an expression is used. Should be compatible with
 /// `unused_variables`'s idea
 /// of what it means for an expression to be "used".
 fn is_used(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
     get_parent_expr(cx, expr).map_or(true, |parent| match parent.kind {
         ExprKind::Assign(_, rhs, _) | ExprKind::AssignOp(_, _, rhs) => SpanlessEq::new(cx).eq_expr(rhs, expr),
         _ => is_used(cx, parent),
     })
 }

 /// Tests whether an expression is in a macro expansion (e.g., something
 /// generated by `#[derive(...)]` or the like).
 fn in_attributes_expansion(expr: &Expr<'_>) -> bool {
     use rustc_span::hygiene::MacroKind;
     if expr.span.from_expansion() {
         let data = expr.span.ctxt().outer_expn_data();
         matches!(data.kind, ExpnKind::Macro(MacroKind::Attr | MacroKind::Derive, _))
     } else {
         false
     }
 }

 /// Tests whether `res` is a variable defined outside a macro.
 fn non_macro_local(cx: &LateContext<'_>, res: def::Res) -> bool {
     if let def::Res::Local(id) = res {
         !cx.tcx.hir().span(id).from_expansion()
     } else {
         false
     }
 }

 impl LintPass {
     fn check_cast(&self, cx: &LateContext<'_>, span: Span, e: &Expr<'_>, ty: &hir::Ty<'_>) {
         if_chain! {
             if let TyKind::Ptr(ref mut_ty) = ty.kind;
             if is_integer_literal(e, 0);
             if !in_constant(cx, e.hir_id);
             then {
                 let (msg, sugg_fn) = match mut_ty.mutbl {
                     Mutability::Mut => ("`0 as *mut _` detected", "ptr::null_mut"),
                     Mutability::Not => ("`0 as *const _` detected", "ptr::null"),
                 };

                 let (sugg, appl) = if let TyKind::Infer = mut_ty.ty.kind {
                     (format!("{}::{sugg_fn}()", self.std_or_core), Applicability::MachineApplicable)
                 } else if let Some(mut_ty_snip) = snippet_opt(cx, mut_ty.ty.span) {
                     (format!("{}::{sugg_fn}::<{mut_ty_snip}>()", self.std_or_core), Applicability::MachineApplicable)
                 } else {
                     // `MaybeIncorrect` as type inference may not work with the suggested code
                     (format!("{}::{sugg_fn}()", self.std_or_core), Applicability::MaybeIncorrect)
                 };
                 span_lint_and_sugg(cx, ZERO_PTR, span, msg, "try", sugg, appl);
             }
         }
     }
 }
	use clippy_utils::diagnostics::{span_lint, span_lint_and_sugg, span_lint_hir_and_then};
	use clippy_utils::source::{snippet, snippet_opt, snippet_with_context};
	use if_chain::if_chain;
	use rustc_errors::Applicability;
	use rustc_hir::intravisit::FnKind;
	use rustc_hir::{
	self as hir, def, BinOpKind, BindingAnnotation, Body, ByRef, Expr, ExprKind, FnDecl, Mutability, PatKind, Stmt,
	StmtKind, TyKind,
	};
	use rustc_lint::{LateContext, LateLintPass};
	use rustc_middle::lint::in_external_macro;
	use rustc_session::{declare_tool_lint, impl_lint_pass};
	use rustc_span::def_id::LocalDefId;
	use rustc_span::hygiene::DesugaringKind;
	use rustc_span::source_map::{ExpnKind, Span};

	use clippy_utils::sugg::Sugg;
	use clippy_utils::{
	get_parent_expr, in_constant, is_integer_literal, is_lint_allowed, is_no_std_crate, iter_input_pats,
	last_path_segment, SpanlessEq,
	};

	use crate::ref_patterns::REF_PATTERNS;

	declare_clippy_lint! {
	/// ### What it does
	/// Checks for function arguments and let bindings denoted as
	/// `ref`.
	///
	/// ### Why is this bad?
	/// The `ref` declaration makes the function take an owned
	/// value, but turns the argument into a reference (which means that the value
	/// is destroyed when exiting the function). This adds not much value: either
	/// take a reference type, or take an owned value and create references in the
	/// body.
	///
	/// For let bindings, `let x = &foo;` is preferred over `let ref x = foo`. The
	/// type of `x` is more obvious with the former.
	///
	/// ### Known problems
	/// If the argument is dereferenced within the function,
	/// removing the `ref` will lead to errors. This can be fixed by removing the
	/// dereferences, e.g., changing `*x` to `x` within the function.
	///
	/// ### Example
	/// ```rust
	/// fn foo(ref _x: u8) {}
	/// ```
	///
	/// Use instead:
	/// ```rust
	/// fn foo(_x: &u8) {}
	/// ```
	#[clippy::version = "pre 1.29.0"]
	pub TOPLEVEL_REF_ARG,
	style,
	"an entire binding declared as `ref`, in a function argument or a `let` statement"
	}
	declare_clippy_lint! {
	/// ### What it does
	/// Checks for the use of bindings with a single leading
	/// underscore.
	///
	/// ### Why is this bad?
	/// A single leading underscore is usually used to indicate
	/// that a binding will not be used. Using such a binding breaks this
	/// expectation.
	///
	/// ### Known problems
	/// The lint does not work properly with desugaring and
	/// macro, it has been allowed in the mean time.
	///
	/// ### Example
	/// ```rust
	/// let _x = 0;
	/// let y = _x + 1; // Here we are using `_x`, even though it has a leading
	/// // underscore. We should rename `_x` to `x`
	/// ```
	#[clippy::version = "pre 1.29.0"]
	pub USED_UNDERSCORE_BINDING,
	pedantic,
	"using a binding which is prefixed with an underscore"
	}

	declare_clippy_lint! {
	/// ### What it does
	/// Checks for the use of short circuit boolean conditions as
	/// a
	/// statement.
	///
	/// ### Why is this bad?
	/// Using a short circuit boolean condition as a statement
	/// may hide the fact that the second part is executed or not depending on the
	/// outcome of the first part.
	///
	/// ### Example
	/// ```rust,ignore
	/// f() && g(); // We should write `if f() { g(); }`.
	/// ```
	#[clippy::version = "pre 1.29.0"]
	pub SHORT_CIRCUIT_STATEMENT,
	complexity,
	"using a short circuit boolean condition as a statement"
	}

	declare_clippy_lint! {
	/// ### What it does
	/// Catch casts from `0` to some pointer type
	///
	/// ### Why is this bad?
	/// This generally means `null` and is better expressed as
	/// {`std`, `core`}`::ptr::`{`null`, `null_mut`}.
	///
	/// ### Example
	/// ```rust
	/// let a = 0 as *const u32;
	/// ```
	///
	/// Use instead:
	/// ```rust
	/// let a = std::ptr::null::<u32>();
	/// ```
	#[clippy::version = "pre 1.29.0"]
	pub ZERO_PTR,
	style,
	"using `0 as *{const, mut} T`"
	}

	pub struct LintPass {
	std_or_core: &'static str,
	}
	impl Default for LintPass {
	fn default() -> Self {
	Self { std_or_core: "std" }
	}
	}
	impl_lint_pass!(LintPass => [
	TOPLEVEL_REF_ARG,
	USED_UNDERSCORE_BINDING,
	SHORT_CIRCUIT_STATEMENT,
	ZERO_PTR,
	]);

	impl<'tcx> LateLintPass<'tcx> for LintPass {
	fn check_crate(&mut self, cx: &LateContext<'_>) {
	if is_no_std_crate(cx) {
	self.std_or_core = "core";
	}
	}

	fn check_fn(
	&mut self,
	cx: &LateContext<'tcx>,
	k: FnKind<'tcx>,
	decl: &'tcx FnDecl<'_>,
	body: &'tcx Body<'_>,
	span: Span,
	_: LocalDefId,
	) {
	if let FnKind::Closure = k {
	// Does not apply to closures
	return;
	}
	if in_external_macro(cx.tcx.sess, span) {
	return;
	}
	for arg in iter_input_pats(decl, body) {
	// Do not emit if clippy::ref_patterns is not allowed to avoid having two lints for the same issue.
	if !is_lint_allowed(cx, REF_PATTERNS, arg.pat.hir_id) {
	return;
	}
	if let PatKind::Binding(BindingAnnotation(ByRef::Yes, _), ..) = arg.pat.kind {
	span_lint(
	cx,
	TOPLEVEL_REF_ARG,
	arg.pat.span,
	"`ref` directly on a function argument is ignored. \
	Consider using a reference type instead",
	);
	}
	}
	}

	fn check_stmt(&mut self, cx: &LateContext<'tcx>, stmt: &'tcx Stmt<'_>) {
	if_chain! {
	if !in_external_macro(cx.tcx.sess, stmt.span);
	if let StmtKind::Local(local) = stmt.kind;
	if let PatKind::Binding(BindingAnnotation(ByRef::Yes, mutabl), .., name, None) = local.pat.kind;
	if let Some(init) = local.init;
	// Do not emit if clippy::ref_patterns is not allowed to avoid having two lints for the same issue.
	if is_lint_allowed(cx, REF_PATTERNS, local.pat.hir_id);
	then {
	let ctxt = local.span.ctxt();
	let mut app = Applicability::MachineApplicable;
	let sugg_init = Sugg::hir_with_context(cx, init, ctxt, "..", &mut app);
	let (mutopt, initref) = if mutabl == Mutability::Mut {
	("mut ", sugg_init.mut_addr())
	} else {
	("", sugg_init.addr())
	};
	let tyopt = if let Some(ty) = local.ty {
	let ty_snip = snippet_with_context(cx, ty.span, ctxt, "_", &mut app).0;
	format!(": &{mutopt}{ty_snip}")
	} else {
	String::new()
	};
	span_lint_hir_and_then(
	cx,
	TOPLEVEL_REF_ARG,
	init.hir_id,
	local.pat.span,
	"`ref` on an entire `let` pattern is discouraged, take a reference with `&` instead",
	\|diag\| {
	diag.span_suggestion(
	stmt.span,
	"try",
	format!(
	"let {name}{tyopt} = {initref};",
	name=snippet(cx, name.span, ".."),
	),
	app,
	);
	}
	);
	}
	};
	if_chain! {
	if let StmtKind::Semi(expr) = stmt.kind;
	if let ExprKind::Binary(ref binop, a, b) = expr.kind;
	if binop.node == BinOpKind::And \|\| binop.node == BinOpKind::Or;
	if let Some(sugg) = Sugg::hir_opt(cx, a);
	then {
	span_lint_hir_and_then(
	cx,
	SHORT_CIRCUIT_STATEMENT,
	expr.hir_id,
	stmt.span,
	"boolean short circuit operator in statement may be clearer using an explicit test",
	\|diag\| {
	let sugg = if binop.node == BinOpKind::Or { !sugg } else { sugg };
	diag.span_suggestion(
	stmt.span,
	"replace it with",
	format!(
	"if {sugg} {{ {}; }}",
	&snippet(cx, b.span, ".."),
	),
	Applicability::MachineApplicable, // snippet
	);
	});
	}
	};
	}

	fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
	if let ExprKind::Cast(e, ty) = expr.kind {
	self.check_cast(cx, expr.span, e, ty);
	return;
	}
	if in_attributes_expansion(expr) \|\| expr.span.is_desugaring(DesugaringKind::Await) {
	// Don't lint things expanded by #[derive(...)], etc or `await` desugaring
	return;
	}
	let sym;
	let binding = match expr.kind {
	ExprKind::Path(ref qpath) if !matches!(qpath, hir::QPath::LangItem(..)) => {
	let binding = last_path_segment(qpath).ident.as_str();
	if binding.starts_with('_') &&
	!binding.starts_with("__") &&
	binding != "_result" && // FIXME: #944
	is_used(cx, expr) &&
	// don't lint if the declaration is in a macro
	non_macro_local(cx, cx.qpath_res(qpath, expr.hir_id))
	{
	Some(binding)
	} else {
	None
	}
	},
	ExprKind::Field(_, ident) => {
	sym = ident.name;
	let name = sym.as_str();
	if name.starts_with('_') && !name.starts_with("__") {
	Some(name)
	} else {
	None
	}
	},
	_ => None,
	};
	if let Some(binding) = binding {
	span_lint(
	cx,
	USED_UNDERSCORE_BINDING,
	expr.span,
	&format!(
	"used binding `{binding}` which is prefixed with an underscore. A leading \
	underscore signals that a binding will not be used"
	),
	);
	}
	}
	}

	/// Heuristic to see if an expression is used. Should be compatible with
	/// `unused_variables`'s idea
	/// of what it means for an expression to be "used".
	fn is_used(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
	get_parent_expr(cx, expr).map_or(true, \|parent\| match parent.kind {
	ExprKind::Assign(_, rhs, _) \| ExprKind::AssignOp(_, _, rhs) => SpanlessEq::new(cx).eq_expr(rhs, expr),
	_ => is_used(cx, parent),
	})
	}

	/// Tests whether an expression is in a macro expansion (e.g., something
	/// generated by `#[derive(...)]` or the like).
	fn in_attributes_expansion(expr: &Expr<'_>) -> bool {
	use rustc_span::hygiene::MacroKind;
	if expr.span.from_expansion() {
	let data = expr.span.ctxt().outer_expn_data();
	matches!(data.kind, ExpnKind::Macro(MacroKind::Attr \| MacroKind::Derive, _))
	} else {
	false
	}
	}

	/// Tests whether `res` is a variable defined outside a macro.
	fn non_macro_local(cx: &LateContext<'_>, res: def::Res) -> bool {
	if let def::Res::Local(id) = res {
	!cx.tcx.hir().span(id).from_expansion()
	} else {
	false
	}
	}

	impl LintPass {
	fn check_cast(&self, cx: &LateContext<'_>, span: Span, e: &Expr<'_>, ty: &hir::Ty<'_>) {
	if_chain! {
	if let TyKind::Ptr(ref mut_ty) = ty.kind;
	if is_integer_literal(e, 0);
	if !in_constant(cx, e.hir_id);
	then {
	let (msg, sugg_fn) = match mut_ty.mutbl {
	Mutability::Mut => ("`0 as *mut _` detected", "ptr::null_mut"),
	Mutability::Not => ("`0 as *const _` detected", "ptr::null"),
	};

	let (sugg, appl) = if let TyKind::Infer = mut_ty.ty.kind {
	(format!("{}::{sugg_fn}()", self.std_or_core), Applicability::MachineApplicable)
	} else if let Some(mut_ty_snip) = snippet_opt(cx, mut_ty.ty.span) {
	(format!("{}::{sugg_fn}::<{mut_ty_snip}>()", self.std_or_core), Applicability::MachineApplicable)
	} else {
	// `MaybeIncorrect` as type inference may not work with the suggested code
	(format!("{}::{sugg_fn}()", self.std_or_core), Applicability::MaybeIncorrect)
	};
	span_lint_and_sugg(cx, ZERO_PTR, span, msg, "try", sugg, appl);
	}
	}
	}
	}