diff --git a/compiler/rustc_lint/messages.ftl b/compiler/rustc_lint/messages.ftl index 16e17fc9d6a..42748512f66 100644 --- a/compiler/rustc_lint/messages.ftl +++ b/compiler/rustc_lint/messages.ftl @@ -213,9 +213,12 @@ lint_expectation = this lint expectation is unfulfilled .note = the `unfulfilled_lint_expectations` lint can't be expected and will always produce this message .rationale = {$rationale} -lint_fn_null_check = function pointers are not nullable, so checking them for null will always return false +lint_fn_null_check_fn_ptr = function pointers are not nullable, so checking them for null will always return false .help = wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value +lint_fn_null_check_ref = references are not nullable, so checking them for null will always return false + .label = expression has type `{$orig_ty}` + lint_for_loops_over_fallibles = for loop over {$article} `{$ty}`. This is more readably written as an `if let` statement .suggestion = consider using `if let` to clear intent diff --git a/compiler/rustc_lint/src/fn_null_check.rs b/compiler/rustc_lint/src/fn_null_check.rs index e3b33463ccf..b036c943f5a 100644 --- a/compiler/rustc_lint/src/fn_null_check.rs +++ b/compiler/rustc_lint/src/fn_null_check.rs @@ -31,7 +31,7 @@ declare_lint! { declare_lint_pass!(IncorrectFnNullChecks => [INCORRECT_FN_NULL_CHECKS]); -fn is_fn_ptr_cast(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool { +fn incorrect_check<'a>(cx: &LateContext<'a>, expr: &Expr<'_>) -> Option> { let mut expr = expr.peel_blocks(); let mut had_at_least_one_cast = false; while let ExprKind::Cast(cast_expr, cast_ty) = expr.kind @@ -39,7 +39,18 @@ fn is_fn_ptr_cast(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool { expr = cast_expr.peel_blocks(); had_at_least_one_cast = true; } - had_at_least_one_cast && cx.typeck_results().expr_ty_adjusted(expr).is_fn() + if !had_at_least_one_cast { + None + } else { + let orig_ty = cx.typeck_results().expr_ty(expr); + if orig_ty.is_fn() { + Some(FnNullCheckDiag::FnPtr) + } else if orig_ty.is_ref() { + Some(FnNullCheckDiag::Ref { orig_ty, label: expr.span }) + } else { + None + } + } } impl<'tcx> LateLintPass<'tcx> for IncorrectFnNullChecks { @@ -54,9 +65,9 @@ impl<'tcx> LateLintPass<'tcx> for IncorrectFnNullChecks { cx.tcx.get_diagnostic_name(def_id), Some(sym::ptr_const_is_null | sym::ptr_is_null) ) - && is_fn_ptr_cast(cx, arg) => + && let Some(diag) = incorrect_check(cx, arg) => { - cx.emit_spanned_lint(INCORRECT_FN_NULL_CHECKS, expr.span, FnNullCheckDiag) + cx.emit_spanned_lint(INCORRECT_FN_NULL_CHECKS, expr.span, diag) } // Catching: @@ -67,17 +78,20 @@ impl<'tcx> LateLintPass<'tcx> for IncorrectFnNullChecks { cx.tcx.get_diagnostic_name(def_id), Some(sym::ptr_const_is_null | sym::ptr_is_null) ) - && is_fn_ptr_cast(cx, receiver) => + && let Some(diag) = incorrect_check(cx, receiver) => { - cx.emit_spanned_lint(INCORRECT_FN_NULL_CHECKS, expr.span, FnNullCheckDiag) + cx.emit_spanned_lint(INCORRECT_FN_NULL_CHECKS, expr.span, diag) } ExprKind::Binary(op, left, right) if matches!(op.node, BinOpKind::Eq) => { let to_check: &Expr<'_>; - if is_fn_ptr_cast(cx, left) { + let diag: FnNullCheckDiag<'_>; + if let Some(ddiag) = incorrect_check(cx, left) { to_check = right; - } else if is_fn_ptr_cast(cx, right) { + diag = ddiag; + } else if let Some(ddiag) = incorrect_check(cx, right) { to_check = left; + diag = ddiag; } else { return; } @@ -89,7 +103,7 @@ impl<'tcx> LateLintPass<'tcx> for IncorrectFnNullChecks { if let ExprKind::Lit(spanned) = cast_expr.kind && let LitKind::Int(v, _) = spanned.node && v == 0 => { - cx.emit_spanned_lint(INCORRECT_FN_NULL_CHECKS, expr.span, FnNullCheckDiag) + cx.emit_spanned_lint(INCORRECT_FN_NULL_CHECKS, expr.span, diag) }, // Catching: @@ -100,7 +114,7 @@ impl<'tcx> LateLintPass<'tcx> for IncorrectFnNullChecks { && let Some(diag_item) = cx.tcx.get_diagnostic_name(def_id) && (diag_item == sym::ptr_null || diag_item == sym::ptr_null_mut) => { - cx.emit_spanned_lint(INCORRECT_FN_NULL_CHECKS, expr.span, FnNullCheckDiag) + cx.emit_spanned_lint(INCORRECT_FN_NULL_CHECKS, expr.span, diag) }, _ => {}, diff --git a/compiler/rustc_lint/src/lints.rs b/compiler/rustc_lint/src/lints.rs index 968172693a9..5f3b5c702d7 100644 --- a/compiler/rustc_lint/src/lints.rs +++ b/compiler/rustc_lint/src/lints.rs @@ -615,9 +615,17 @@ pub struct ExpectationNote { // fn_null_check.rs #[derive(LintDiagnostic)] -#[diag(lint_fn_null_check)] -#[help] -pub struct FnNullCheckDiag; +pub enum FnNullCheckDiag<'a> { + #[diag(lint_fn_null_check_fn_ptr)] + #[help(lint_help)] + FnPtr, + #[diag(lint_fn_null_check_ref)] + Ref { + orig_ty: Ty<'a>, + #[label] + label: Span, + }, +} // for_loops_over_fallibles.rs #[derive(LintDiagnostic)] diff --git a/tests/ui/lint/fn_null_check.rs b/tests/ui/lint/fn_null_check.rs index 7f01f2c4283..87b120fc131 100644 --- a/tests/ui/lint/fn_null_check.rs +++ b/tests/ui/lint/fn_null_check.rs @@ -3,6 +3,7 @@ fn main() { let fn_ptr = main; + // ------------- Function pointers --------------- if (fn_ptr as *mut ()).is_null() {} //~^ WARN function pointers are not nullable if (fn_ptr as *const u8).is_null() {} @@ -20,6 +21,26 @@ fn main() { if (fn_ptr as fn() as *const ()).is_null() {} //~^ WARN function pointers are not nullable + // ---------------- References ------------------ + if (&mut 8 as *mut i32).is_null() {} + //~^ WARN references are not nullable + if (&8 as *const i32).is_null() {} + //~^ WARN references are not nullable + if (&8 as *const i32) == std::ptr::null() {} + //~^ WARN references are not nullable + let ref_num = &8; + if (ref_num as *const i32) == std::ptr::null() {} + //~^ WARN references are not nullable + if (b"\0" as *const u8).is_null() {} + //~^ WARN references are not nullable + if ("aa" as *const str).is_null() {} + //~^ WARN references are not nullable + if (&[1, 2] as *const i32).is_null() {} + //~^ WARN references are not nullable + if (&mut [1, 2] as *mut i32) == std::ptr::null_mut() {} + //~^ WARN references are not nullable + + // ---------------------------------------------- const ZPTR: *const () = 0 as *const _; const NOT_ZPTR: *const () = 1 as *const _; diff --git a/tests/ui/lint/fn_null_check.stderr b/tests/ui/lint/fn_null_check.stderr index 0398c0da50f..7a08c5bda2b 100644 --- a/tests/ui/lint/fn_null_check.stderr +++ b/tests/ui/lint/fn_null_check.stderr @@ -1,5 +1,5 @@ warning: function pointers are not nullable, so checking them for null will always return false - --> $DIR/fn_null_check.rs:6:8 + --> $DIR/fn_null_check.rs:7:8 | LL | if (fn_ptr as *mut ()).is_null() {} | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -8,7 +8,7 @@ LL | if (fn_ptr as *mut ()).is_null() {} = note: `#[warn(incorrect_fn_null_checks)]` on by default warning: function pointers are not nullable, so checking them for null will always return false - --> $DIR/fn_null_check.rs:8:8 + --> $DIR/fn_null_check.rs:9:8 | LL | if (fn_ptr as *const u8).is_null() {} | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -16,7 +16,7 @@ LL | if (fn_ptr as *const u8).is_null() {} = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value warning: function pointers are not nullable, so checking them for null will always return false - --> $DIR/fn_null_check.rs:10:8 + --> $DIR/fn_null_check.rs:11:8 | LL | if (fn_ptr as *const ()) == std::ptr::null() {} | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -24,7 +24,7 @@ LL | if (fn_ptr as *const ()) == std::ptr::null() {} = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value warning: function pointers are not nullable, so checking them for null will always return false - --> $DIR/fn_null_check.rs:12:8 + --> $DIR/fn_null_check.rs:13:8 | LL | if (fn_ptr as *mut ()) == std::ptr::null_mut() {} | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -32,7 +32,7 @@ LL | if (fn_ptr as *mut ()) == std::ptr::null_mut() {} = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value warning: function pointers are not nullable, so checking them for null will always return false - --> $DIR/fn_null_check.rs:14:8 + --> $DIR/fn_null_check.rs:15:8 | LL | if (fn_ptr as *const ()) == (0 as *const ()) {} | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -40,7 +40,7 @@ LL | if (fn_ptr as *const ()) == (0 as *const ()) {} = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value warning: function pointers are not nullable, so checking them for null will always return false - --> $DIR/fn_null_check.rs:16:8 + --> $DIR/fn_null_check.rs:17:8 | LL | if <*const _>::is_null(fn_ptr as *const ()) {} | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -48,7 +48,7 @@ LL | if <*const _>::is_null(fn_ptr as *const ()) {} = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value warning: function pointers are not nullable, so checking them for null will always return false - --> $DIR/fn_null_check.rs:18:8 + --> $DIR/fn_null_check.rs:19:8 | LL | if (fn_ptr as *mut fn() as *const fn() as *const ()).is_null() {} | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -56,12 +56,76 @@ LL | if (fn_ptr as *mut fn() as *const fn() as *const ()).is_null() {} = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value warning: function pointers are not nullable, so checking them for null will always return false - --> $DIR/fn_null_check.rs:20:8 + --> $DIR/fn_null_check.rs:21:8 | LL | if (fn_ptr as fn() as *const ()).is_null() {} | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value -warning: 8 warnings emitted +warning: references are not nullable, so checking them for null will always return false + --> $DIR/fn_null_check.rs:25:8 + | +LL | if (&mut 8 as *mut i32).is_null() {} + | ^------^^^^^^^^^^^^^^^^^^^^^^^ + | | + | expression has type `&mut i32` + +warning: references are not nullable, so checking them for null will always return false + --> $DIR/fn_null_check.rs:27:8 + | +LL | if (&8 as *const i32).is_null() {} + | ^--^^^^^^^^^^^^^^^^^^^^^^^^^ + | | + | expression has type `&i32` + +warning: references are not nullable, so checking them for null will always return false + --> $DIR/fn_null_check.rs:29:8 + | +LL | if (&8 as *const i32) == std::ptr::null() {} + | ^--^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | | + | expression has type `&i32` + +warning: references are not nullable, so checking them for null will always return false + --> $DIR/fn_null_check.rs:32:8 + | +LL | if (ref_num as *const i32) == std::ptr::null() {} + | ^-------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | | + | expression has type `&i32` + +warning: references are not nullable, so checking them for null will always return false + --> $DIR/fn_null_check.rs:34:8 + | +LL | if (b"\0" as *const u8).is_null() {} + | ^-----^^^^^^^^^^^^^^^^^^^^^^^^ + | | + | expression has type `&[u8; 1]` + +warning: references are not nullable, so checking them for null will always return false + --> $DIR/fn_null_check.rs:36:8 + | +LL | if ("aa" as *const str).is_null() {} + | ^----^^^^^^^^^^^^^^^^^^^^^^^^^ + | | + | expression has type `&str` + +warning: references are not nullable, so checking them for null will always return false + --> $DIR/fn_null_check.rs:38:8 + | +LL | if (&[1, 2] as *const i32).is_null() {} + | ^-------^^^^^^^^^^^^^^^^^^^^^^^^^ + | | + | expression has type `&[i32; 2]` + +warning: references are not nullable, so checking them for null will always return false + --> $DIR/fn_null_check.rs:40:8 + | +LL | if (&mut [1, 2] as *mut i32) == std::ptr::null_mut() {} + | ^-----------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | | + | expression has type `&mut [i32; 2]` + +warning: 16 warnings emitted