added error for closures case in impl

Author: Kivooeo

compiler/rustc_hir_analysis/messages.ftl

@@ -65,6 +65,9 @@ hir_analysis_cannot_capture_late_bound_lifetime =
     cannot capture late-bound lifetime in {$what}
     .label = lifetime defined here
 
+hir_analysis_monomorphization_inherent_impl_for_closure =
+    cannot define inherent `impl` for closure types
+
 hir_analysis_cannot_capture_late_bound_ty =
     cannot capture late-bound type parameter in {$what}
     .label = parameter defined here

compiler/rustc_hir_analysis/src/coherence/inherent_impls.rs

@@ -195,11 +195,10 @@ impl<'tcx> InherentCollect<'tcx> {
             | ty::Closure(..)
             | ty::CoroutineClosure(..)
             | ty::Coroutine(..)
-            | ty::CoroutineWitness(..)
-            | ty::Alias(ty::Free, _)
-            | ty::Bound(..)
-            | ty::Placeholder(_)
-            | ty::Infer(_) => {
+            | ty::CoroutineWitness(..) => {
+                Err(self.tcx.dcx().emit_err(errors::InherentImplForClosure { span: item_span }))
+            }
+            ty::Alias(ty::Free, _) | ty::Bound(..) | ty::Placeholder(_) | ty::Infer(_) => {
                 bug!("unexpected impl self type of impl: {:?} {:?}", id, self_ty);
             }
             // We could bail out here, but that will silence other useful errors.

compiler/rustc_hir_analysis/src/coherence/orphan.rs

@@ -230,10 +230,12 @@ pub(crate) fn orphan_check_impl(
             ty::Closure(..)
             | ty::CoroutineClosure(..)
             | ty::Coroutine(..)
-            | ty::CoroutineWitness(..)
-            | ty::Bound(..)
-            | ty::Placeholder(..)
-            | ty::Infer(..) => {
+            | ty::CoroutineWitness(..) => {
+                return Err(tcx
+                    .dcx()
+                    .emit_err(errors::InherentImplForClosure { span: tcx.def_span(impl_def_id) }));
+            }
+            ty::Bound(..) | ty::Placeholder(..) | ty::Infer(..) => {
                 let sp = tcx.def_span(impl_def_id);
                 span_bug!(sp, "weird self type for autotrait impl")
             }

compiler/rustc_hir_analysis/src/errors.rs

@@ -59,6 +59,13 @@ pub(crate) struct AssocKindMismatchWrapInBracesSugg {
     pub hi: Span,
 }
 
+#[derive(Diagnostic)]
+#[diag(hir_analysis_monomorphization_inherent_impl_for_closure)]
+pub struct InherentImplForClosure {
+    #[primary_span]
+    pub span: Span,
+}
+
 #[derive(Diagnostic)]
 #[diag(hir_analysis_assoc_item_is_private, code = E0624)]
 pub(crate) struct AssocItemIsPrivate {

tests/ui/closures/impl-closure-147146.rs

@@ -0,0 +1,9 @@
+impl typeof(|| {}) {}
+//~^ ERROR `typeof` is a reserved keyword but unimplemented
+//~| ERROR cannot define inherent `impl` for closure types
+
+unsafe impl Send for typeof(|| {}) {}
+//~^ ERROR `typeof` is a reserved keyword but unimplemented
+//~| ERROR cannot define inherent `impl` for closure types
+
+fn main() {}

tests/ui/closures/impl-closure-147146.stderr

@@ -0,0 +1,27 @@
+error[E0516]: `typeof` is a reserved keyword but unimplemented
+  --> $DIR/impl-closure-147146.rs:1:6
+   |
+LL | impl typeof(|| {}) {}
+   |      ^^^^^^^^^^^^^ reserved keyword
+
+error[E0516]: `typeof` is a reserved keyword but unimplemented
+  --> $DIR/impl-closure-147146.rs:5:22
+   |
+LL | unsafe impl Send for typeof(|| {}) {}
+   |                      ^^^^^^^^^^^^^ reserved keyword
+
+error: cannot define inherent `impl` for closure types
+  --> $DIR/impl-closure-147146.rs:5:1
+   |
+LL | unsafe impl Send for typeof(|| {}) {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: cannot define inherent `impl` for closure types
+  --> $DIR/impl-closure-147146.rs:1:1
+   |
+LL | impl typeof(|| {}) {}
+   | ^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0516`.