Rollup merge of #133774 - dingxiangfei2009:translatable-coerce-pointee-errors, r=jieyouxu

Make CoercePointee errors translatable

Tracked by #123430

Just in case that a translatable error message would become a blocker to stabilization, this PR switches over to fluent error messages, which also slightly improve the wordings and use more accurate span information.

cc `@Darksonn` `@traviscross`

4 files changed, 78 insertions, 48 deletions

diff --git a/compiler/rustc_builtin_macros/messages.ftl b/compiler/rustc_builtin_macros/messages.ftl
index 6ebc2fd870c..c05d44cb452 100644
--- a/compiler/rustc_builtin_macros/messages.ftl
+++ b/compiler/rustc_builtin_macros/messages.ftl
@@ -94,6 +94,21 @@ builtin_macros_cfg_accessible_indeterminate = cannot determine whether the path
 builtin_macros_cfg_accessible_literal_path = `cfg_accessible` path cannot be a literal
 builtin_macros_cfg_accessible_multiple_paths = multiple `cfg_accessible` paths are specified
 builtin_macros_cfg_accessible_unspecified_path = `cfg_accessible` path is not specified
+
+builtin_macros_coerce_pointee_requires_maybe_sized = `derive(CoercePointee)` requires `{$name}` to be marked `?Sized`
+
+builtin_macros_coerce_pointee_requires_one_field = `CoercePointee` can only be derived on `struct`s with at least one field
+
+builtin_macros_coerce_pointee_requires_one_generic = `CoercePointee` can only be derived on `struct`s that are generic over at least one type
+
+builtin_macros_coerce_pointee_requires_one_pointee = exactly one generic type parameter must be marked as `#[pointee]` to derive `CoercePointee` traits
+
+builtin_macros_coerce_pointee_requires_transparent = `CoercePointee` can only be derived on `struct`s with `#[repr(transparent)]`
+
+builtin_macros_coerce_pointee_too_many_pointees = only one type parameter can be marked as `#[pointee]` when deriving `CoercePointee` traits
+    .label = here another type parameter is marked as `#[pointee]`
+
+
 builtin_macros_concat_bytes_array = cannot concatenate doubly nested array
     .note = byte strings are treated as arrays of bytes
     .help = try flattening the array
diff --git a/compiler/rustc_builtin_macros/src/deriving/coerce_pointee.rs b/compiler/rustc_builtin_macros/src/deriving/coerce_pointee.rs
index 8adb9a3f4b0..3bd8f899a4a 100644
--- a/compiler/rustc_builtin_macros/src/deriving/coerce_pointee.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/coerce_pointee.rs
@@ -9,6 +9,7 @@ use rustc_ast::{
 use rustc_attr as attr;
 use rustc_data_structures::flat_map_in_place::FlatMapInPlace;
 use rustc_expand::base::{Annotatable, ExtCtxt};
+use rustc_macros::Diagnostic;
 use rustc_span::symbol::{Ident, sym};
 use rustc_span::{Span, Symbol};
 use thin_vec::{ThinVec, thin_vec};
@@ -38,12 +39,7 @@ pub(crate) fn expand_deriving_coerce_pointee(
                 .any(|r| matches!(r, attr::ReprTransparent))
         });
         if !is_transparent {
-            cx.dcx()
-                .struct_span_err(
-                    span,
-                    "`CoercePointee` can only be derived on `struct`s with `#[repr(transparent)]`",
-                )
-                .emit();
+            cx.dcx().emit_err(RequireTransparent { span });
             return;
         }
         if !matches!(
@@ -51,22 +47,12 @@ pub(crate) fn expand_deriving_coerce_pointee(
             VariantData::Struct { fields, recovered: _ } | VariantData::Tuple(fields, _)
                 if !fields.is_empty())
         {
-            cx.dcx()
-                .struct_span_err(
-                    span,
-                    "`CoercePointee` can only be derived on `struct`s with at least one field",
-                )
-                .emit();
+            cx.dcx().emit_err(RequireOneField { span });
             return;
         }
         (aitem.ident, g)
     } else {
-        cx.dcx()
-            .struct_span_err(
-                span,
-                "`CoercePointee` can only be derived on `struct`s with `#[repr(transparent)]`",
-            )
-            .emit();
+        cx.dcx().emit_err(RequireTransparent { span });
         return;
     };
 
@@ -95,10 +81,7 @@ pub(crate) fn expand_deriving_coerce_pointee(
 
     let pointee_param_idx = if type_params.is_empty() {
         // `#[derive(CoercePointee)]` requires at least one generic type on the target `struct`
-        cx.dcx().struct_span_err(
-            span,
-            "`CoercePointee` can only be derived on `struct`s that are generic over at least one type",
-        ).emit();
+        cx.dcx().emit_err(RequireOneGeneric { span });
         return;
     } else if type_params.len() == 1 {
         // Regardless of the only type param being designed as `#[pointee]` or not, we can just use it as such
@@ -111,19 +94,11 @@ pub(crate) fn expand_deriving_coerce_pointee(
         match (pointees.next(), pointees.next()) {
             (Some((idx, _span)), None) => idx,
             (None, _) => {
-                cx.dcx().struct_span_err(
-                    span,
-                    "exactly one generic type parameter must be marked as #[pointee] to derive CoercePointee traits",
-                ).emit();
+                cx.dcx().emit_err(RequireOnePointee { span });
                 return;
             }
             (Some((_, one)), Some((_, another))) => {
-                cx.dcx()
-                    .struct_span_err(
-                        vec![one, another],
-                        "only one type parameter can be marked as `#[pointee]` when deriving CoercePointee traits",
-                    )
-                    .emit();
+                cx.dcx().emit_err(TooManyPointees { one, another });
                 return;
             }
         }
@@ -181,15 +156,10 @@ pub(crate) fn expand_deriving_coerce_pointee(
                 pointee_ty_ident.name,
             )
         {
-            cx.dcx()
-                .struct_span_err(
-                    pointee_ty_ident.span,
-                    format!(
-                        "`derive(CoercePointee)` requires {} to be marked `?Sized`",
-                        pointee_ty_ident.name
-                    ),
-                )
-                .emit();
+            cx.dcx().emit_err(RequiresMaybeSized {
+                span: pointee_ty_ident.span,
+                name: pointee_ty_ident.name.to_ident_string(),
+            });
             return;
         }
         let arg = GenericArg::Type(s_ty.clone());
@@ -459,3 +429,48 @@ impl<'a, 'b> rustc_ast::visit::Visitor<'a> for AlwaysErrorOnGenericParam<'a, 'b>
         }
     }
 }
+
+#[derive(Diagnostic)]
+#[diag(builtin_macros_coerce_pointee_requires_transparent)]
+struct RequireTransparent {
+    #[primary_span]
+    span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(builtin_macros_coerce_pointee_requires_one_field)]
+struct RequireOneField {
+    #[primary_span]
+    span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(builtin_macros_coerce_pointee_requires_one_generic)]
+struct RequireOneGeneric {
+    #[primary_span]
+    span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(builtin_macros_coerce_pointee_requires_one_pointee)]
+struct RequireOnePointee {
+    #[primary_span]
+    span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(builtin_macros_coerce_pointee_too_many_pointees)]
+struct TooManyPointees {
+    #[primary_span]
+    one: Span,
+    #[label]
+    another: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(builtin_macros_coerce_pointee_requires_maybe_sized)]
+struct RequiresMaybeSized {
+    #[primary_span]
+    span: Span,
+    name: String,
+}
diff --git a/tests/ui/deriving/deriving-coerce-pointee-neg.rs b/tests/ui/deriving/deriving-coerce-pointee-neg.rs
index deef35cdf70..da25c854c54 100644
--- a/tests/ui/deriving/deriving-coerce-pointee-neg.rs
+++ b/tests/ui/deriving/deriving-coerce-pointee-neg.rs
@@ -29,7 +29,7 @@ struct NoFieldUnit<'a, #[pointee] T: ?Sized>();
 struct NoGeneric<'a>(&'a u8);
 
 #[derive(CoercePointee)]
-//~^ ERROR: exactly one generic type parameter must be marked as #[pointee] to derive CoercePointee traits
+//~^ ERROR: exactly one generic type parameter must be marked as `#[pointee]` to derive `CoercePointee` traits
 #[repr(transparent)]
 struct AmbiguousPointee<'a, T1: ?Sized, T2: ?Sized> {
     a: (&'a T1, &'a T2),
@@ -38,7 +38,7 @@ struct AmbiguousPointee<'a, T1: ?Sized, T2: ?Sized> {
 #[derive(CoercePointee)]
 #[repr(transparent)]
 struct TooManyPointees<'a, #[pointee] A: ?Sized, #[pointee] B: ?Sized>((&'a A, &'a B));
-//~^ ERROR: only one type parameter can be marked as `#[pointee]` when deriving CoercePointee traits
+//~^ ERROR: only one type parameter can be marked as `#[pointee]` when deriving `CoercePointee` traits
 
 #[derive(CoercePointee)]
 //~^ ERROR: `CoercePointee` can only be derived on `struct`s with `#[repr(transparent)]`
@@ -49,7 +49,7 @@ struct NotTransparent<'a, #[pointee] T: ?Sized> {
 #[derive(CoercePointee)]
 #[repr(transparent)]
 struct NoMaybeSized<'a, #[pointee] T> {
-    //~^ ERROR: `derive(CoercePointee)` requires T to be marked `?Sized`
+    //~^ ERROR: `derive(CoercePointee)` requires `T` to be marked `?Sized`
     ptr: &'a T,
 }
 
diff --git a/tests/ui/deriving/deriving-coerce-pointee-neg.stderr b/tests/ui/deriving/deriving-coerce-pointee-neg.stderr
index e590d636d0e..c1e8be49d37 100644
--- a/tests/ui/deriving/deriving-coerce-pointee-neg.stderr
+++ b/tests/ui/deriving/deriving-coerce-pointee-neg.stderr
@@ -30,7 +30,7 @@ LL | #[derive(CoercePointee)]
    |
    = note: this error originates in the derive macro `CoercePointee` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: exactly one generic type parameter must be marked as #[pointee] to derive CoercePointee traits
+error: exactly one generic type parameter must be marked as `#[pointee]` to derive `CoercePointee` traits
   --> $DIR/deriving-coerce-pointee-neg.rs:31:10
    |
 LL | #[derive(CoercePointee)]
@@ -38,11 +38,11 @@ LL | #[derive(CoercePointee)]
    |
    = note: this error originates in the derive macro `CoercePointee` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: only one type parameter can be marked as `#[pointee]` when deriving CoercePointee traits
+error: only one type parameter can be marked as `#[pointee]` when deriving `CoercePointee` traits
   --> $DIR/deriving-coerce-pointee-neg.rs:40:39
    |
 LL | struct TooManyPointees<'a, #[pointee] A: ?Sized, #[pointee] B: ?Sized>((&'a A, &'a B));
-   |                                       ^                     ^
+   |                                       ^                     - here another type parameter is marked as `#[pointee]`
 
 error: `CoercePointee` can only be derived on `struct`s with `#[repr(transparent)]`
   --> $DIR/deriving-coerce-pointee-neg.rs:43:10
@@ -52,7 +52,7 @@ LL | #[derive(CoercePointee)]
    |
    = note: this error originates in the derive macro `CoercePointee` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: `derive(CoercePointee)` requires T to be marked `?Sized`
+error: `derive(CoercePointee)` requires `T` to be marked `?Sized`
   --> $DIR/deriving-coerce-pointee-neg.rs:51:36
    |
 LL | struct NoMaybeSized<'a, #[pointee] T> {