From 73b1ca899858b7079bec54a6e4f29941cbb8d0bd Mon Sep 17 00:00:00 2001
From: Martin Fischer <martin@push-f.com>
Date: Wed, 24 Nov 2021 19:30:32 +0100
Subject: better error message for <Self as Foo>::X
---
src/lib.rs | 3 +++
src/transform.rs | 15 ++++++++++++++-
ui-tests/src/bin/qualified_self.rs | 10 ++++++++++
ui-tests/src/bin/qualified_self.stderr | 5 +++++
4 files changed, 32 insertions(+), 1 deletion(-)
create mode 100644 ui-tests/src/bin/qualified_self.rs
create mode 100644 ui-tests/src/bin/qualified_self.stderr
diff --git a/src/lib.rs b/src/lib.rs
index 277720e..00b9772 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -229,6 +229,9 @@ pub fn dynamize(_attr: TokenStream, input: TokenStream) -> TokenStream {
n
)
}
+ MethodError::Transform(TransformError::QualifiedSelfAssociatedType) => {
+ return abort!(span, "dynamize does not support associated types of a qualified Self")
+ }
MethodError::UnconvertedAssocType => {
return abort!(span, "dynamize does not support associated types here")
}
diff --git a/src/transform.rs b/src/transform.rs
index 8de4c96..594d383 100644
--- a/src/transform.rs
+++ b/src/transform.rs
@@ -3,7 +3,7 @@ use std::collections::HashMap;
use proc_macro2::Span;
use quote::quote;
use syn::{
- spanned::Spanned, GenericArgument, Generics, Ident, PathArguments, TraitBound, Type,
+ spanned::Spanned, GenericArgument, Generics, Ident, PathArguments, QSelf, TraitBound, Type,
TypeParamBound, TypePath, TypeReference, TypeTraitObject, WherePredicate,
};
@@ -11,6 +11,7 @@ use crate::{
filter_map_assoc_paths, match_assoc_type,
parse_assoc_type::{BoxType, DestType},
parse_trait_sig::{MethodError, TypeTransform},
+ path_is_assoc_type,
syn_utils::{iter_path, iter_type, type_arguments_mut},
};
@@ -26,6 +27,7 @@ pub enum TransformError {
UnsupportedType,
ExpectedAtLeastNTypes(usize),
AssocTypeAfterFirstNTypes(usize, Ident),
+ QualifiedSelfAssociatedType,
}
impl TypeConverter<'_> {
@@ -57,6 +59,17 @@ impl TypeConverter<'_> {
}
pub fn convert_type(&self, type_: &mut Type) -> Result<TypeTransform, (Span, TransformError)> {
+ if let Type::Path(TypePath {
+ qself: Some(QSelf { ty, .. }),
+ ..
+ }) = type_
+ {
+ if let Type::Path(TypePath { qself: None, path }) = ty.as_ref() {
+ if path_is_assoc_type(path) {
+ return Err((path.span(), TransformError::QualifiedSelfAssociatedType));
+ }
+ }
+ }
if !iter_type(type_).any(match_assoc_type) {
return Ok(TypeTransform::NoOp);
}
diff --git a/ui-tests/src/bin/qualified_self.rs b/ui-tests/src/bin/qualified_self.rs
new file mode 100644
index 0000000..b02f623
--- /dev/null
+++ b/ui-tests/src/bin/qualified_self.rs
@@ -0,0 +1,10 @@
+trait Foo {
+ type X: Into<String>;
+}
+
+#[dynamize::dynamize]
+trait Bar: Foo {
+ fn test(&self) -> <Self as Foo>::X;
+}
+
+fn main() {}
diff --git a/ui-tests/src/bin/qualified_self.stderr b/ui-tests/src/bin/qualified_self.stderr
new file mode 100644
index 0000000..1b5f9f9
--- /dev/null
+++ b/ui-tests/src/bin/qualified_self.stderr
@@ -0,0 +1,5 @@
+error: dynamize does not support associated types of a qualified Self
+ --> src/bin/qualified_self.rs:7:24
+ |
+7 | fn test(&self) -> <Self as Foo>::X;
+ | ^^^^
--
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