output looks fantastic

Author: nhamovitz

clippy_lints/src/trailing_zero_sized_array_without_repr_c.rs

@@ -1,8 +1,9 @@
-use clippy_utils::diagnostics::span_lint_and_sugg;
-// use clippy_utils::is_integer_const;
 use clippy_utils::consts::{miri_to_const, Constant};
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::snippet;
 use rustc_errors::Applicability;
-use rustc_hir::{HirId, Item, ItemKind, TyKind, VariantData};
+use rustc_hir::def_id::LocalDefId;
+use rustc_hir::{Item, ItemKind, TyKind, VariantData};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::sym;
@@ -46,26 +47,14 @@ impl<'tcx> LateLintPass<'tcx> for TrailingZeroSizedArrayWithoutReprC {
     fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'tcx>) {
         dbg!(item.ident);
 
-        let hir_id = cx.tcx.hir().local_def_id_to_hir_id(item.def_id);
-        let hir_id2 = item.hir_id();
-        dbg!(hir_id);
-        dbg!(hir_id2);
-        dbg!(hir_id == hir_id2);
-
-        let span1 = cx.tcx.hir().span(hir_id);
-        let span2 = item.span;
-        dbg!(span1);
-        dbg!(span2);
-        dbg!(span1 == span2);
-
-        if is_struct_with_trailing_zero_sized_array(cx, item) && !has_repr_c(cx, hir_id) {
+        if is_struct_with_trailing_zero_sized_array(cx, item) && !has_repr_c(cx, item.def_id) {
             span_lint_and_sugg(
                 cx,
                 TRAILING_ZERO_SIZED_ARRAY_WITHOUT_REPR_C,
-                span2,
-                "trailing zero-sized array in a struct which isn't marked `#[repr(C)]`",
+                item.span,
+                "trailing zero-sized array in a struct which is not marked `#[repr(C)]`",
                 "try",
-                "#[repr(C)]".to_string(),
+                format!("#[repr(C)]\n{}", snippet(cx, item.span, "..")),
                 Applicability::MaybeIncorrect,
             );
         }
@@ -101,13 +90,14 @@ fn is_struct_with_trailing_zero_sized_array(cx: &LateContext<'tcx>, item: &'tcx
     false
 }
 
-fn has_repr_c(cx: &LateContext<'tcx>, hir_id: HirId) -> bool {
+fn has_repr_c(cx: &LateContext<'tcx>, def_id: LocalDefId) -> bool {
+    let hir_id = cx.tcx.hir().local_def_id_to_hir_id(def_id);
     let attrs = cx.tcx.hir().attrs(hir_id);
+
     // NOTE: Can there ever be more than one `repr` attribute?
     // other `repr` syms: repr, repr128, repr_align, repr_align_enum, repr_no_niche, repr_packed,
     // repr_simd, repr_transparent
-
-    if let Some(repr_attr) = attrs.iter().find(|attr| attr.has_name(sym::repr)) {
+    if let Some(_repr_attr) = attrs.iter().find(|attr| attr.has_name(sym::repr)) {
         // eprintln!("repr: true");
         true
     } else {

tests/ui/trailing_zero_sized_array_without_repr_c.rs

@@ -1,5 +1,7 @@
 #![warn(clippy::trailing_zero_sized_array_without_repr_c)]
 
+// #![feature(const_generics_defaults)]
+
 struct RarelyUseful {
     field: i32,
     last: [usize; 0],
@@ -15,62 +17,97 @@ struct OnlyFieldIsZeroSizeArray {
     first_and_last: [usize; 0],
 }
 
-// struct GenericArrayType<T> {
-//     field: i32,
-//     last: [T; 0],
-// }
+struct GenericArrayType<T> {
+    field: i32,
+    last: [T; 0],
+}
 
-// struct SizedArray {
-//     field: i32,
-//     last: [usize; 1],
-// }
+struct SizedArray {
+    field: i32,
+    last: [usize; 1],
+}
 
-// const ZERO: usize = 0;
-// struct ZeroSizedFromExternalConst {
-//     field: i32,
-//     last: [usize; ZERO],
-// }
+const ZERO: usize = 0;
+struct ZeroSizedFromExternalConst {
+    field: i32,
+    last: [usize; ZERO],
+}
+
+const ONE: usize = 1;
+struct NonZeroSizedFromExternalConst {
+    field: i32,
+    last: [usize; ONE],
+}
 
-// const ONE: usize = 1;
-// struct NonZeroSizedFromExternalConst {
+#[allow(clippy::eq_op)] // lmao im impressed
+const fn compute_zero() -> usize {
+    (4 + 6) - (2 * 5)
+}
+struct UsingFunction {
+    field: i32,
+    last: [usize; compute_zero()],
+}
+
+// #[repr(C)]
+// struct ConstParamOk<const N: usize = 0> {
 //     field: i32,
-//     last: [usize; ONE],
+//     last: [usize; N]
 // }
 
-// #[allow(clippy::eq_op)] // lmao im impressed
-// const fn compute_zero() -> usize {
-//     (4 + 6) - (2 * 5)
-// }
-// struct UsingFunction {
+// struct ConstParamLint<const N: usize = 0> {
 //     field: i32,
-//     last: [usize; compute_zero()],
+//     last: [usize; N]
 // }
 
-// // TODO: same
-// #[repr(packed)]
-// struct ReprPacked {
-//     small: u8,
-//     medium: i32,
-//     weird: [u64; 0],
-// }
 
-// // TODO: actually, uh,, 
-// #[repr(align(64))]
-// struct ReprAlign {
-//     field: i32,
-//     last: [usize; 0],
-// }
-// #[repr(C, align(64))]
-// struct ReprCAlign {
-//     field: i32,
-//     last: [usize; 0],
-// }
+// TODO: actually, uh,,
+#[repr(packed)]
+struct ReprPacked {
+    small: u8,
+    medium: i32,
+    weird: [u64; 0],
+}
 
-// #[repr(C)]
-// enum DontLintAnonymousStructsFromDesuraging {
-//     A(u32),
-//     B(f32, [u64; 0]),
-//     C { x: u32, y: [u64; 0] },
-// }
+// same
+#[repr(align(64))]
+struct ReprAlign {
+    field: i32,
+    last: [usize; 0],
+}
 
-fn main() {}
+// same
+#[repr(C, align(64))]
+struct ReprCAlign {
+    field: i32,
+    last: [usize; 0],
+}
+
+#[repr(C)]
+enum DontLintAnonymousStructsFromDesuraging {
+    A(u32),
+    B(f32, [u64; 0]),
+    C { x: u32, y: [u64; 0] },
+}
+
+struct LotsOfFields {
+    f1: u32,
+    f2: u32,
+    f3: u32,
+    f4: u32,
+    f5: u32,
+    f6: u32,
+    f7: u32,
+    f8: u32,
+    f9: u32,
+    f10: u32,
+    f11: u32,
+    f12: u32,
+    f13: u32,
+    f14: u32,
+    f15: u32,
+    f16: u32,
+    last: [usize; 0],
+}
+
+fn main() {
+}