Added checks for attribute in type case

Author: Kivooeo

compiler/rustc_parse/messages.ftl

@@ -71,6 +71,17 @@ parse_attr_without_generics = attribute without generic parameters
 parse_attribute_on_param_type = attributes cannot be applied to a function parameter's type
     .label = attributes are not allowed here
 
+parse_attribute_on_type = attributes cannot be applied to a type
+    .label = attributes are not allowed here
+    .suggestion = remove attribute from here
+
+parse_attribute_on_generic_type = attributes cannot be applied to generic type arguments
+    .label = attributes are not allowed here
+    .suggestion = remove attribute from here
+
+parse_attribute_on_empty_generic = attributes cannot be applied here
+    .label = attributes are not allowed here
+
 parse_bad_assoc_type_bounds = bounds on associated types do not belong here
     .label = belongs in `where` clause
 

compiler/rustc_parse/src/errors.rs

@@ -1489,6 +1489,34 @@ pub(crate) struct AttributeOnParamType {
     pub span: Span,
 }
 
+#[derive(Diagnostic)]
+#[diag(parse_attribute_on_type)]
+pub(crate) struct AttributeOnType {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+    #[suggestion(code = "", applicability = "machine-applicable", style = "verbose")]
+    pub fix_span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(parse_attribute_on_generic_type)]
+pub(crate) struct AttributeOnGenericType {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+    #[suggestion(code = "", applicability = "machine-applicable", style = "verbose")]
+    pub fix_span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(parse_attribute_on_empty_generic)]
+pub(crate) struct AttributeOnEmptyGeneric {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+}
+
 #[derive(Diagnostic)]
 #[diag(parse_pattern_method_param_without_body, code = E0642)]
 pub(crate) struct PatternMethodParamWithoutBody {

compiler/rustc_parse/src/parser/attr_wrapper.rs

@@ -69,6 +69,10 @@ impl AttrWrapper {
         self.attrs
     }
 
+    pub(super) fn attrs(&self) -> &AttrVec {
+        &self.attrs
+    }
+
     /// Prepend `self.attrs` to `attrs`.
     // FIXME: require passing an NT to prevent misuse of this method
     pub(super) fn prepend_to_nt_inner(mut self, attrs: &mut AttrVec) {

compiler/rustc_parse/src/parser/path.rs

@@ -17,8 +17,8 @@ use super::ty::{AllowPlus, RecoverQPath, RecoverReturnSign};
 use super::{Parser, Restrictions, TokenType};
 use crate::ast::{PatKind, TyKind};
 use crate::errors::{
-    self, FnPathFoundNamedParams, PathFoundAttributeInParams, PathFoundCVariadicParams,
-    PathSingleColon, PathTripleColon,
+    self, AttributeOnEmptyGeneric, AttributeOnGenericType, FnPathFoundNamedParams,
+    PathFoundAttributeInParams, PathFoundCVariadicParams, PathSingleColon, PathTripleColon,
 };
 use crate::exp;
 use crate::parser::{CommaRecoveryMode, RecoverColon, RecoverComma};
@@ -880,6 +880,15 @@ impl<'a> Parser<'a> {
         &mut self,
         ty_generics: Option<&Generics>,
     ) -> PResult<'a, Option<GenericArg>> {
+        let mut attr_span: Option<Span> = None;
+        if self.token == token::Pound && self.look_ahead(1, |t| *t == token::OpenBracket) {
+            // Parse attribute.
+            let attrs_wrapper = self.parse_outer_attributes()?;
+            if !attrs_wrapper.is_empty() {
+                let raw_attrs = attrs_wrapper.attrs();
+                attr_span = Some(raw_attrs[0].span.to(raw_attrs.last().unwrap().span));
+            }
+        }
         let start = self.token.span;
         let arg = if self.check_lifetime() && self.look_ahead(1, |t| !t.is_like_plus()) {
             // Parse lifetime argument.
@@ -934,6 +943,10 @@ impl<'a> Parser<'a> {
             }
         } else if self.token.is_keyword(kw::Const) {
             return self.recover_const_param_declaration(ty_generics);
+        } else if let Some(attr_span) = attr_span {
+            // Handle case where attribute is present but no valid generic argument follows.
+            let guar = self.dcx().emit_err(AttributeOnEmptyGeneric { span: attr_span });
+            return Ok(Some(GenericArg::Type(self.mk_ty(attr_span, TyKind::Err(guar)))));
         } else {
             // Fall back by trying to parse a const-expr expression. If we successfully do so,
             // then we should report an error that it needs to be wrapped in braces.
@@ -953,6 +966,18 @@ impl<'a> Parser<'a> {
                 }
             }
         };
+
+        if let Some(attr_span) = attr_span
+            && !(arg.span().is_empty() || arg.span().is_dummy())
+        {
+            let guar = self.dcx().emit_err(AttributeOnGenericType {
+                span: attr_span,
+                fix_span: attr_span.until(arg.span()),
+            });
+
+            return Ok(Some(GenericArg::Type(self.mk_ty(attr_span, TyKind::Err(guar)))));
+        }
+
         Ok(Some(arg))
     }
 

compiler/rustc_parse/src/parser/ty.rs

@@ -14,10 +14,10 @@ use thin_vec::{ThinVec, thin_vec};
 
 use super::{Parser, PathStyle, SeqSep, TokenType, Trailing};
 use crate::errors::{
-    self, DynAfterMut, ExpectedFnPathFoundFnKeyword, ExpectedMutOrConstInRawPointerType,
-    FnPtrWithGenerics, FnPtrWithGenericsSugg, HelpUseLatestEdition, InvalidDynKeyword,
-    LifetimeAfterMut, NeedPlusAfterTraitObjectLifetime, NestedCVariadicType,
-    ReturnTypesUseThinArrow,
+    self, AttributeOnType, DynAfterMut, ExpectedFnPathFoundFnKeyword,
+    ExpectedMutOrConstInRawPointerType, FnPtrWithGenerics, FnPtrWithGenericsSugg,
+    HelpUseLatestEdition, InvalidDynKeyword, LifetimeAfterMut, NeedPlusAfterTraitObjectLifetime,
+    NestedCVariadicType, ReturnTypesUseThinArrow,
 };
 use crate::parser::item::FrontMatterParsingMode;
 use crate::{exp, maybe_recover_from_interpolated_ty_qpath};
@@ -253,6 +253,24 @@ impl<'a> Parser<'a> {
     ) -> PResult<'a, P<Ty>> {
         let allow_qpath_recovery = recover_qpath == RecoverQPath::Yes;
         maybe_recover_from_interpolated_ty_qpath!(self, allow_qpath_recovery);
+        if self.token == token::Pound && self.look_ahead(1, |t| *t == token::OpenBracket) {
+            let attrs_wrapper = self.parse_outer_attributes()?;
+            if !attrs_wrapper.is_empty() {
+                let raw_attrs = attrs_wrapper.take_for_recovery(self.psess);
+
+                let attr_span = raw_attrs[0].span.to(raw_attrs.last().unwrap().span);
+
+                let ty_after_attr = self.parse_ty()?;
+                let full_span_for_err = attr_span.to(ty_after_attr.span);
+
+                let guar = self.dcx().emit_err(AttributeOnType {
+                    span: attr_span,
+                    fix_span: attr_span.until(ty_after_attr.span),
+                });
+
+                return Ok(self.mk_ty(full_span_for_err, TyKind::Err(guar)));
+            }
+        }
 
         if let Some(ty) = self.eat_metavar_seq_with_matcher(
             |mv_kind| matches!(mv_kind, MetaVarKind::Ty { .. }),

tests/ui/parser/attribute-on-type.rs

@@ -0,0 +1,65 @@
+//! Regression test for: <https://github.com/rust-lang/rust/issues/144132>
+//!                      <https://github.com/rust-lang/rust/issues/135017>
+
+struct Foo<T>(T);
+struct Bar<'a>(&'a i32);
+struct Baz<const N: usize>(i32);
+
+fn main() {
+    let foo: Foo<#[cfg(not(wrong))] String> = todo!();
+    //~^ ERROR attributes cannot be applied to generic type arguments
+
+    let _: Bar<#[cfg(any())] 'static> = todo!();
+    //~^ ERROR attributes cannot be applied to generic type arguments
+
+    let _: Baz<#[cfg(any())] 42> = todo!();
+    //~^ ERROR attributes cannot be applied to generic type arguments
+    //~| ERROR type provided when a constant was expected
+
+    let _: Foo<#[cfg(not(wrong))]String> = todo!();
+    //~^ ERROR attributes cannot be applied to generic type arguments
+
+    let _: Bar<#[cfg(any())]       'static> = todo!();
+    //~^ ERROR attributes cannot be applied to generic type arguments
+
+    let _: Baz<#[cfg(any())]> = todo!();
+    //~^ ERROR attributes cannot be applied here
+    //~| ERROR type provided when a constant was expected
+
+    let _: Foo<#[cfg(not(wrong))]> = todo!();
+    //~^ ERROR attributes cannot be applied here
+
+    let _: Bar<#[cfg(any())]> = todo!();
+    //~^ ERROR attributes cannot be applied here
+
+    let _generic: Box<#[attr] i32> = Box::new(1);
+    //~^ ERROR attributes cannot be applied to generic type arguments
+
+    let _assignment: #[attr] i32 = Box::new(1);
+    //~^ ERROR attributes cannot be applied to a type
+
+    let _complex: Vec<#[derive(Debug)] String> = vec![];
+    //~^ ERROR attributes cannot be applied to generic type arguments
+
+    let _nested: Box<Vec<#[cfg(feature = "test")] u64>> = Box::new(vec![]);
+    //~^ ERROR attributes cannot be applied to generic type arguments
+}
+
+fn f(_param: #[attr] i32) {}
+//~^ ERROR attributes cannot be applied to a function parameter's type
+
+fn g() -> #[attr] i32 { 0 }
+//~^ ERROR attributes cannot be applied to a type
+
+struct S {
+    field: #[attr] i32,
+    //~^ ERROR attributes cannot be applied to a type
+    field1: (#[attr] i32, i32),
+    //~^ ERROR attributes cannot be applied to a type
+}
+
+type Tuple = (#[attr] i32, String);
+//~^ ERROR attributes cannot be applied to a type
+
+impl #[attr] S {}
+//~^ ERROR attributes cannot be applied to a type