Auto merge of #144458 - compiler-errors:no-witness-mini, r=lcnr

Remove the witness type from coroutine *args* (without actually removing the type)

This does as much of rust-lang/rust#144157 as we can without having to break rust-lang/rust#143545 and/or introduce some better way of handling higher ranked assumptions.

Namely, it:
* Stalls coroutines based off of the *coroutine* type rather than the witness type.
* Reworks the dtorck constraint hack to not rely on the witness type.
* Removes the witness type from the args of the coroutine, eagerly creating the type for nested obligations when needed (auto/clone impls).

I'll experiment with actually removing the witness type in a follow-up.

r? lcnr

2 files changed, 12 insertions, 25 deletions

diff --git a/compiler/rustc_middle/src/ty/generic_args.rs b/compiler/rustc_middle/src/ty/generic_args.rs
index 7d34d8df3f3..b02abb5ab43 100644
--- a/compiler/rustc_middle/src/ty/generic_args.rs
+++ b/compiler/rustc_middle/src/ty/generic_args.rs
@@ -96,14 +96,12 @@ impl<'tcx> rustc_type_ir::inherent::GenericArgs<TyCtxt<'tcx>> for ty::GenericArg
                 signature_parts_ty,
                 tupled_upvars_ty,
                 coroutine_captures_by_ref_ty,
-                coroutine_witness_ty,
             ] => ty::CoroutineClosureArgsParts {
                 parent_args,
                 closure_kind_ty: closure_kind_ty.expect_ty(),
                 signature_parts_ty: signature_parts_ty.expect_ty(),
                 tupled_upvars_ty: tupled_upvars_ty.expect_ty(),
                 coroutine_captures_by_ref_ty: coroutine_captures_by_ref_ty.expect_ty(),
-                coroutine_witness_ty: coroutine_witness_ty.expect_ty(),
             },
             _ => bug!("closure args missing synthetics"),
         }
@@ -111,23 +109,16 @@ impl<'tcx> rustc_type_ir::inherent::GenericArgs<TyCtxt<'tcx>> for ty::GenericArg
 
     fn split_coroutine_args(self) -> ty::CoroutineArgsParts<TyCtxt<'tcx>> {
         match self[..] {
-            [
-                ref parent_args @ ..,
-                kind_ty,
-                resume_ty,
-                yield_ty,
-                return_ty,
-                witness,
-                tupled_upvars_ty,
-            ] => ty::CoroutineArgsParts {
-                parent_args,
-                kind_ty: kind_ty.expect_ty(),
-                resume_ty: resume_ty.expect_ty(),
-                yield_ty: yield_ty.expect_ty(),
-                return_ty: return_ty.expect_ty(),
-                witness: witness.expect_ty(),
-                tupled_upvars_ty: tupled_upvars_ty.expect_ty(),
-            },
+            [ref parent_args @ .., kind_ty, resume_ty, yield_ty, return_ty, tupled_upvars_ty] => {
+                ty::CoroutineArgsParts {
+                    parent_args,
+                    kind_ty: kind_ty.expect_ty(),
+                    resume_ty: resume_ty.expect_ty(),
+                    yield_ty: yield_ty.expect_ty(),
+                    return_ty: return_ty.expect_ty(),
+                    tupled_upvars_ty: tupled_upvars_ty.expect_ty(),
+                }
+            }
             _ => bug!("coroutine args missing synthetics"),
         }
     }
diff --git a/compiler/rustc_middle/src/ty/print/pretty.rs b/compiler/rustc_middle/src/ty/print/pretty.rs
index 5c44b10ba71..71eac294f15 100644
--- a/compiler/rustc_middle/src/ty/print/pretty.rs
+++ b/compiler/rustc_middle/src/ty/print/pretty.rs
@@ -913,9 +913,7 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
                         " yield_ty=",
                         print(args.as_coroutine().yield_ty()),
                         " return_ty=",
-                        print(args.as_coroutine().return_ty()),
-                        " witness=",
-                        print(args.as_coroutine().witness())
+                        print(args.as_coroutine().return_ty())
                     );
                 }
 
@@ -1035,9 +1033,7 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
                         " upvar_tys=",
                         print(args.as_coroutine_closure().tupled_upvars_ty()),
                         " coroutine_captures_by_ref_ty=",
-                        print(args.as_coroutine_closure().coroutine_captures_by_ref_ty()),
-                        " coroutine_witness_ty=",
-                        print(args.as_coroutine_closure().coroutine_witness_ty())
+                        print(args.as_coroutine_closure().coroutine_captures_by_ref_ty())
                     );
                 }
                 p!("}}");