const eval of FRTs (they are uninhabited, so not really much to do)

Author: BennoLossin

compiler/rustc_const_eval/src/const_eval/valtrees.rs

@@ -161,7 +161,8 @@ fn const_to_valtree_inner<'tcx>(
             branches(ecx, place, def.variant(variant).fields.len(), def.is_enum().then_some(variant), num_nodes)
         }
 
-        ty::Never
+        ty::Field(..)
+        | ty::Never
         | ty::Error(_)
         | ty::Foreign(..)
         | ty::Infer(ty::FreshIntTy(_))
@@ -323,7 +324,9 @@ pub fn valtree_to_const_value<'tcx>(
 
             op_to_const(&ecx, &place.into(), /* for diagnostics */ false)
         }
-        ty::Never
+
+        ty::Field(..)
+        | ty::Never
         | ty::Error(_)
         | ty::Foreign(..)
         | ty::Infer(ty::FreshIntTy(_))

compiler/rustc_const_eval/src/interpret/intrinsics.rs

@@ -188,6 +188,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                     | ty::CoroutineWitness(..)
                     | ty::UnsafeBinder(_)
                     | ty::Never
+                    | ty::Field(..)
                     | ty::Tuple(_)
                     | ty::Error(_) => ConstValue::from_target_usize(0u64, &tcx),
                 };

compiler/rustc_const_eval/src/interpret/stack.rs

@@ -507,6 +507,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                 | ty::Closure(..)
                 | ty::CoroutineClosure(..)
                 | ty::Never
+                | ty::Field(..)
                 | ty::Error(_) => true,
 
                 ty::Str | ty::Slice(_) | ty::Dynamic(_, _, ty::Dyn) | ty::Foreign(..) => false,

compiler/rustc_const_eval/src/interpret/validity.rs

@@ -771,6 +771,7 @@ impl<'rt, 'tcx, M: Machine<'tcx>> ValidityVisitor<'rt, 'tcx, M> {
                 interp_ok(true)
             }
             ty::Never => throw_validation_failure!(self.path, NeverVal),
+            ty::Field(..) => throw_validation_failure!(self.path, NeverVal),
             ty::Foreign(..) | ty::FnDef(..) => {
                 // Nothing to check.
                 interp_ok(true)

compiler/rustc_const_eval/src/util/type_name.rs

@@ -1,4 +1,5 @@
 use std::fmt::Write;
+use std::ops::ControlFlow;
 
 use rustc_data_structures::intern::Interned;
 use rustc_hir::def_id::{CrateNum, DefId};
@@ -58,6 +59,29 @@ impl<'tcx> Printer<'tcx> for TypeNamePrinter<'tcx> {
             | ty::CoroutineClosure(def_id, args)
             | ty::Coroutine(def_id, args) => self.print_def_path(def_id, args),
             ty::Foreign(def_id) => self.print_def_path(def_id, &[]),
+            ty::Field(container, field_path) => {
+                write!(self, "field_of!(")?;
+                self.print_type(container)?;
+                write!(self, ", ")?;
+                field_path
+                    .walk(self.tcx, container, |_, name, _, last| {
+                        match write!(self, "{name}") {
+                            Ok(()) => ControlFlow::Continue(()),
+                            Err(err) => ControlFlow::Break(Err(err)),
+                        }?;
+                        if !last {
+                            match write!(self, ".") {
+                                Ok(()) => ControlFlow::Continue(()),
+                                Err(err) => ControlFlow::Break(Err(err)),
+                            }
+                        } else {
+                            ControlFlow::Continue(())
+                        }
+                    })
+                    .unwrap_or(Ok(()))?;
+                write!(self, ")")?;
+                Ok(())
+            }
 
             ty::Alias(ty::Free, _) => bug!("type_name: unexpected free alias"),
             ty::Alias(ty::Inherent, _) => bug!("type_name: unexpected inherent projection"),

tests/debuginfo/function-names.rs

@@ -38,7 +38,7 @@
 // Const generic parameter
 // gdb-command:info functions -q function_names::const_generic_fn.*
 // gdb-check:[...]static fn function_names::const_generic_fn_bool<false>();
-// gdb-check:[...]static fn function_names::const_generic_fn_non_int<{CONST#ffa3db4ca1d52dce}>();
+// gdb-check:[...]static fn function_names::const_generic_fn_non_int<{CONST#5177fe61e1757625}>();
 // gdb-check:[...]static fn function_names::const_generic_fn_signed_int<-7>();
 // gdb-check:[...]static fn function_names::const_generic_fn_unsigned_int<14>();