Add and correct tests of impl lookup on generic interfaces (#4974)

These tests expose cycles during deduction, when the generic parameters
in an impl statement require deduction and the impl clause that
satisfies them comes after the one containing the generic parameters.
This causes the same impl to be looked at repeatedly, and produces a
cycle diagnostic.

---------

Co-authored-by: Geoff Romer <gromer@google.com>

toolchain/check/testdata/builtin_conversions/no_prelude/fail_todo_convert_facet_value_value_to_generic_facet_value_value.carbon

@@ -22,30 +22,47 @@ library "[[@TEST_NAME]]";
 
 import Core;
 
+interface Edible {}
+
 class Grass {}
+impl Grass as Edible {}
 
 interface Animal {}
 interface Eats(Food:! type) {}
 
-fn Feed[Food:! type, T:! Eats(Food)](e: T, food: Food) {}
-// CHECK:STDERR: fail_todo_convert_facet_value_value_to_generic_facet_value_value.carbon:[[@LINE+10]]:62: error: cannot implicitly convert from `type` to `Eats(Food)` [ImplicitAsConversionFailure]
-// CHECK:STDERR: fn HandleAnimal[T:! Animal, Food:! type](a: T, food: Food) { Feed(a, food); }
-// CHECK:STDERR:                                                              ^~~~~~~~~~~~~
-// CHECK:STDERR: fail_todo_convert_facet_value_value_to_generic_facet_value_value.carbon:[[@LINE+7]]:62: note: type `type` does not implement interface `Core.ImplicitAs(Eats(Food))` [MissingImplInMemberAccessNote]
-// CHECK:STDERR: fn HandleAnimal[T:! Animal, Food:! type](a: T, food: Food) { Feed(a, food); }
-// CHECK:STDERR:                                                              ^~~~~~~~~~~~~
-// CHECK:STDERR: fail_todo_convert_facet_value_value_to_generic_facet_value_value.carbon:[[@LINE-7]]:1: note: while deducing parameters of generic declared here [DeductionGenericHere]
-// CHECK:STDERR: fn Feed[Food:! type, T:! Eats(Food)](e: T, food: Food) {}
-// CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-// CHECK:STDERR:
-fn HandleAnimal[T:! Animal, Food:! type](a: T, food: Food) { Feed(a, food); }
+// This impl is looked at for "does Goat impl Animal" first, which requires a
+// recursive query in deduction that is the same "does Goat impl Animal", which
+// can land us back looking at this impl again. So we require a way to eliminate
+// this impl without doing deduction in order to avoid the cycle.
+impl forall [T:! Animal, U:! Edible] T as Eats(U) {}
 
 class Goat {}
 impl Goat as Animal {}
 
-impl forall [T:! Animal] T as Eats(Grass) {}
+fn Feed[Food:! Edible, T:! Eats(Food)](e: T, food: Food) {}
+fn HandleAnimal[T:! Animal, Food:! Edible](a: T, food: Food) { Feed(a, food); }
 
 fn F() {
+  // CHECK:STDERR: fail_todo_convert_facet_value_value_to_generic_facet_value_value.carbon:[[@LINE+20]]:3: error: cycle found in lookup of interface <TODO: interface name> for type `Goat` [ImplLookupCycle]
+  // CHECK:STDERR:   HandleAnimal({} as Goat, {} as Grass);
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: fail_todo_convert_facet_value_value_to_generic_facet_value_value.carbon:[[@LINE-12]]:1: note: while deducing parameters of generic declared here [DeductionGenericHere]
+  // CHECK:STDERR: impl forall [T:! Animal, U:! Edible] T as Eats(U) {}
+  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: fail_todo_convert_facet_value_value_to_generic_facet_value_value.carbon:[[@LINE-9]]:1: note: while deducing parameters of generic declared here [DeductionGenericHere]
+  // CHECK:STDERR: fn HandleAnimal[T:! Animal, Food:! Edible](a: T, food: Food) { Feed(a, food); }
+  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
+  // CHECK:STDERR: fail_todo_convert_facet_value_value_to_generic_facet_value_value.carbon:[[@LINE+10]]:3: error: cycle found in lookup of interface <TODO: interface name> for type `Goat` [ImplLookupCycle]
+  // CHECK:STDERR:   HandleAnimal({} as Goat, {} as Grass);
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: fail_todo_convert_facet_value_value_to_generic_facet_value_value.carbon:[[@LINE-22]]:1: note: while deducing parameters of generic declared here [DeductionGenericHere]
+  // CHECK:STDERR: impl forall [T:! Animal, U:! Edible] T as Eats(U) {}
+  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: fail_todo_convert_facet_value_value_to_generic_facet_value_value.carbon:[[@LINE-19]]:1: note: while deducing parameters of generic declared here [DeductionGenericHere]
+  // CHECK:STDERR: fn HandleAnimal[T:! Animal, Food:! Edible](a: T, food: Food) { Feed(a, food); }
+  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
   HandleAnimal({} as Goat, {} as Grass);
 }
 
@@ -148,182 +165,209 @@ fn F() {
 // CHECK:STDOUT: --- fail_todo_convert_facet_value_value_to_generic_facet_value_value.carbon
 // CHECK:STDOUT:
 // CHECK:STDOUT: constants {
+// CHECK:STDOUT:   %Edible.type: type = facet_type <@Edible> [concrete]
+// CHECK:STDOUT:   %Self.9af: %Edible.type = bind_symbolic_name Self, 0 [symbolic]
 // CHECK:STDOUT:   %Grass: type = class_type @Grass [concrete]
 // CHECK:STDOUT:   %empty_struct_type: type = struct_type {} [concrete]
 // CHECK:STDOUT:   %complete_type.357: <witness> = complete_type_witness %empty_struct_type [concrete]
+// CHECK:STDOUT:   %empty_tuple.type: type = tuple_type () [concrete]
+// CHECK:STDOUT:   %impl_witness.1bc: <witness> = impl_witness () [concrete]
 // CHECK:STDOUT:   %Animal.type: type = facet_type <@Animal> [concrete]
 // CHECK:STDOUT:   %Self.fd4: %Animal.type = bind_symbolic_name Self, 0 [symbolic]
 // CHECK:STDOUT:   %Food.8b3: type = bind_symbolic_name Food, 0 [symbolic]
 // CHECK:STDOUT:   %Food.patt.e01: type = symbolic_binding_pattern Food, 0 [symbolic]
 // CHECK:STDOUT:   %Eats.type.ba2: type = generic_interface_type @Eats [concrete]
-// CHECK:STDOUT:   %empty_tuple.type: type = tuple_type () [concrete]
 // CHECK:STDOUT:   %Eats.generic: %Eats.type.ba2 = struct_value () [concrete]
 // CHECK:STDOUT:   %Eats.type.6c0: type = facet_type <@Eats, @Eats(%Food.8b3)> [symbolic]
 // CHECK:STDOUT:   %Self.4eb: %Eats.type.6c0 = bind_symbolic_name Self, 1 [symbolic]
-// CHECK:STDOUT:   %T.4eb: %Eats.type.6c0 = bind_symbolic_name T, 1 [symbolic]
-// CHECK:STDOUT:   %T.patt.41f: %Eats.type.6c0 = symbolic_binding_pattern T, 1 [symbolic]
-// CHECK:STDOUT:   %T.as_type.7b9: type = facet_access_type %T.4eb [symbolic]
-// CHECK:STDOUT:   %Feed.type: type = fn_type @Feed [concrete]
-// CHECK:STDOUT:   %Feed: %Feed.type = struct_value () [concrete]
-// CHECK:STDOUT:   %require_complete.c74: <witness> = require_complete_type %T.as_type.7b9 [symbolic]
-// CHECK:STDOUT:   %require_complete.4ae: <witness> = require_complete_type %Food.8b3 [symbolic]
 // CHECK:STDOUT:   %T.fd4: %Animal.type = bind_symbolic_name T, 0 [symbolic]
 // CHECK:STDOUT:   %T.patt.a9c: %Animal.type = symbolic_binding_pattern T, 0 [symbolic]
-// CHECK:STDOUT:   %Food.336: type = bind_symbolic_name Food, 1 [symbolic]
-// CHECK:STDOUT:   %Food.patt.7a9: type = symbolic_binding_pattern Food, 1 [symbolic]
+// CHECK:STDOUT:   %U: %Edible.type = bind_symbolic_name U, 1 [symbolic]
+// CHECK:STDOUT:   %U.patt: %Edible.type = symbolic_binding_pattern U, 1 [symbolic]
 // CHECK:STDOUT:   %T.as_type.2ad: type = facet_access_type %T.fd4 [symbolic]
+// CHECK:STDOUT:   %U.as_type: type = facet_access_type %U [symbolic]
+// CHECK:STDOUT:   %Eats.type.f54c3d.1: type = facet_type <@Eats, @Eats(%U.as_type)> [symbolic]
+// CHECK:STDOUT:   %require_complete.42532a.1: <witness> = require_complete_type %Eats.type.f54c3d.1 [symbolic]
+// CHECK:STDOUT:   %impl_witness.c7c36b.1: <witness> = impl_witness (), @impl.2(%T.fd4, %U) [symbolic]
+// CHECK:STDOUT:   %Goat: type = class_type @Goat [concrete]
+// CHECK:STDOUT:   %Food.9af: %Edible.type = bind_symbolic_name Food, 0 [symbolic]
+// CHECK:STDOUT:   %Food.patt.0b7: %Edible.type = symbolic_binding_pattern Food, 0 [symbolic]
+// CHECK:STDOUT:   %Food.as_type.952: type = facet_access_type %Food.9af [symbolic]
+// CHECK:STDOUT:   %Eats.type.b39: type = facet_type <@Eats, @Eats(%Food.as_type.952)> [symbolic]
+// CHECK:STDOUT:   %T.223: %Eats.type.b39 = bind_symbolic_name T, 1 [symbolic]
+// CHECK:STDOUT:   %T.patt.f09: %Eats.type.b39 = symbolic_binding_pattern T, 1 [symbolic]
+// CHECK:STDOUT:   %T.as_type.212: type = facet_access_type %T.223 [symbolic]
+// CHECK:STDOUT:   %Feed.type: type = fn_type @Feed [concrete]
+// CHECK:STDOUT:   %Feed: %Feed.type = struct_value () [concrete]
+// CHECK:STDOUT:   %require_complete.fe6: <witness> = require_complete_type %T.as_type.212 [symbolic]
+// CHECK:STDOUT:   %require_complete.005: <witness> = require_complete_type %Food.as_type.952 [symbolic]
+// CHECK:STDOUT:   %Food.5fe: %Edible.type = bind_symbolic_name Food, 1 [symbolic]
+// CHECK:STDOUT:   %Food.patt.551: %Edible.type = symbolic_binding_pattern Food, 1 [symbolic]
+// CHECK:STDOUT:   %Food.as_type.fae: type = facet_access_type %Food.5fe [symbolic]
 // CHECK:STDOUT:   %HandleAnimal.type: type = fn_type @HandleAnimal [concrete]
 // CHECK:STDOUT:   %HandleAnimal: %HandleAnimal.type = struct_value () [concrete]
 // CHECK:STDOUT:   %require_complete.234: <witness> = require_complete_type %T.as_type.2ad [symbolic]
-// CHECK:STDOUT:   %require_complete.b54: <witness> = require_complete_type %Food.336 [symbolic]
-// CHECK:STDOUT:   %Eats.type.3ec: type = facet_type <@Eats, @Eats(%Food.336)> [symbolic]
-// CHECK:STDOUT:   %require_complete.588: <witness> = require_complete_type %Eats.type.3ec [symbolic]
-// CHECK:STDOUT:   %T.8b3: type = bind_symbolic_name T, 0 [symbolic]
-// CHECK:STDOUT:   %ImplicitAs.type.d62: type = facet_type <@ImplicitAs, @ImplicitAs(%T.8b3)> [symbolic]
-// CHECK:STDOUT:   %Self.519: %ImplicitAs.type.d62 = bind_symbolic_name Self, 1 [symbolic]
-// CHECK:STDOUT:   %T.patt.e01: type = symbolic_binding_pattern T, 0 [symbolic]
-// CHECK:STDOUT:   %Convert.type.275: type = fn_type @Convert, @ImplicitAs(%T.8b3) [symbolic]
-// CHECK:STDOUT:   %Convert.42e: %Convert.type.275 = struct_value () [symbolic]
-// CHECK:STDOUT:   %Self.as_type: type = facet_access_type %Self.519 [symbolic]
-// CHECK:STDOUT:   %ImplicitAs.assoc_type.837: type = assoc_entity_type %ImplicitAs.type.d62 [symbolic]
-// CHECK:STDOUT:   %assoc0.43db8b.1: %ImplicitAs.assoc_type.837 = assoc_entity element0, imports.%Core.import_ref.207961.1 [symbolic]
-// CHECK:STDOUT:   %ImplicitAs.type.dd1: type = facet_type <@ImplicitAs, @ImplicitAs(%Eats.type.3ec)> [symbolic]
-// CHECK:STDOUT:   %require_complete.959: <witness> = require_complete_type %ImplicitAs.type.dd1 [symbolic]
-// CHECK:STDOUT:   %Convert.type.d69: type = fn_type @Convert, @ImplicitAs(%Eats.type.3ec) [symbolic]
-// CHECK:STDOUT:   %Convert.561: %Convert.type.d69 = struct_value () [symbolic]
-// CHECK:STDOUT:   %ImplicitAs.assoc_type.163: type = assoc_entity_type %ImplicitAs.type.dd1 [symbolic]
-// CHECK:STDOUT:   %assoc0.676: %ImplicitAs.assoc_type.163 = assoc_entity element0, imports.%Core.import_ref.207961.1 [symbolic]
-// CHECK:STDOUT:   %assoc0.43db8b.2: %ImplicitAs.assoc_type.837 = assoc_entity element0, imports.%Core.import_ref.207961.2 [symbolic]
-// CHECK:STDOUT:   %Goat: type = class_type @Goat [concrete]
-// CHECK:STDOUT:   %impl_witness.1bc: <witness> = impl_witness () [concrete]
-// CHECK:STDOUT:   %Eats.type.1ae: type = facet_type <@Eats, @Eats(%Grass)> [concrete]
-// CHECK:STDOUT:   %impl_witness.8fd: <witness> = impl_witness (), @impl.2(%T.fd4) [symbolic]
+// CHECK:STDOUT:   %require_complete.444: <witness> = require_complete_type %Food.as_type.fae [symbolic]
+// CHECK:STDOUT:   %Eats.type.f54c3d.2: type = facet_type <@Eats, @Eats(%Food.as_type.fae)> [symbolic]
+// CHECK:STDOUT:   %require_complete.42532a.2: <witness> = require_complete_type %Eats.type.f54c3d.2 [symbolic]
+// CHECK:STDOUT:   %impl_witness.c7c36b.2: <witness> = impl_witness (), @impl.2(%T.fd4, %Food.5fe) [symbolic]
+// CHECK:STDOUT:   %Eats.facet.b56: %Eats.type.f54c3d.2 = facet_value %T.as_type.2ad, %impl_witness.c7c36b.2 [symbolic]
+// CHECK:STDOUT:   %Feed.specific_fn.f4b: <specific function> = specific_function %Feed, @Feed(%Food.5fe, %Eats.facet.b56) [symbolic]
 // CHECK:STDOUT:   %F.type: type = fn_type @F [concrete]
 // CHECK:STDOUT:   %F: %F.type = struct_value () [concrete]
 // CHECK:STDOUT:   %Goat.val: %Goat = struct_value () [concrete]
 // CHECK:STDOUT:   %Grass.val: %Grass = struct_value () [concrete]
 // CHECK:STDOUT:   %Animal.facet: %Animal.type = facet_value %Goat, %impl_witness.1bc [concrete]
-// CHECK:STDOUT:   %HandleAnimal.specific_fn: <specific function> = specific_function %HandleAnimal, @HandleAnimal(%Animal.facet, %Grass) [concrete]
+// CHECK:STDOUT:   %Edible.facet: %Edible.type = facet_value %Grass, %impl_witness.1bc [concrete]
+// CHECK:STDOUT:   %HandleAnimal.specific_fn: <specific function> = specific_function %HandleAnimal, @HandleAnimal(%Animal.facet, %Edible.facet) [concrete]
+// CHECK:STDOUT:   %Eats.type.1ae: type = facet_type <@Eats, @Eats(%Grass)> [concrete]
 // CHECK:STDOUT:   %complete_type.004: <witness> = complete_type_witness %Eats.type.1ae [concrete]
-// CHECK:STDOUT:   %ImplicitAs.type.849: type = facet_type <@ImplicitAs, @ImplicitAs(%Eats.type.1ae)> [concrete]
-// CHECK:STDOUT:   %complete_type.eef: <witness> = complete_type_witness %ImplicitAs.type.849 [concrete]
+// CHECK:STDOUT:   %impl_witness.15d: <witness> = impl_witness (), @impl.2(%Animal.facet, %Edible.facet) [concrete]
+// CHECK:STDOUT:   %Eats.facet.c76: %Eats.type.1ae = facet_value %Goat, %impl_witness.15d [concrete]
+// CHECK:STDOUT:   %Feed.specific_fn.e8d: <specific function> = specific_function %Feed, @Feed(%Edible.facet, %Eats.facet.c76) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
 // CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
-// CHECK:STDOUT:     .ImplicitAs = %Core.ImplicitAs
 // CHECK:STDOUT:     import Core//default
 // CHECK:STDOUT:   }
-// CHECK:STDOUT:   %Core.import_ref.f6b058.1: type = import_ref Core//default, loc4_22, loaded [symbolic = @ImplicitAs.%T (constants.%T.8b3)]
-// CHECK:STDOUT:   %Core.import_ref.ff5 = import_ref Core//default, inst26 [no loc], unloaded
-// CHECK:STDOUT:   %Core.import_ref.630: @ImplicitAs.%ImplicitAs.assoc_type (%ImplicitAs.assoc_type.837) = import_ref Core//default, loc5_32, loaded [symbolic = @ImplicitAs.%assoc0 (constants.%assoc0.43db8b.2)]
-// CHECK:STDOUT:   %Core.Convert = import_ref Core//default, Convert, unloaded
-// CHECK:STDOUT:   %Core.import_ref.f6b058.2: type = import_ref Core//default, loc4_22, loaded [symbolic = @ImplicitAs.%T (constants.%T.8b3)]
-// CHECK:STDOUT:   %Core.import_ref.ce1: @ImplicitAs.%ImplicitAs.type (%ImplicitAs.type.d62) = import_ref Core//default, inst26 [no loc], loaded [symbolic = @ImplicitAs.%Self (constants.%Self.519)]
-// CHECK:STDOUT:   %Core.import_ref.207961.1 = import_ref Core//default, loc5_32, unloaded
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
 // CHECK:STDOUT:     .Core = imports.%Core
+// CHECK:STDOUT:     .Edible = %Edible.decl
 // CHECK:STDOUT:     .Grass = %Grass.decl
 // CHECK:STDOUT:     .Animal = %Animal.decl
 // CHECK:STDOUT:     .Eats = %Eats.decl
+// CHECK:STDOUT:     .Goat = %Goat.decl
 // CHECK:STDOUT:     .Feed = %Feed.decl
 // CHECK:STDOUT:     .HandleAnimal = %HandleAnimal.decl
-// CHECK:STDOUT:     .Goat = %Goat.decl
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Core.import = import Core
+// CHECK:STDOUT:   %Edible.decl: type = interface_decl @Edible [concrete = constants.%Edible.type] {} {}
 // CHECK:STDOUT:   %Grass.decl: type = class_decl @Grass [concrete = constants.%Grass] {} {}
+// CHECK:STDOUT:   impl_decl @impl.1 [concrete] {} {
+// CHECK:STDOUT:     %Grass.ref: type = name_ref Grass, file.%Grass.decl [concrete = constants.%Grass]
+// CHECK:STDOUT:     %Edible.ref: type = name_ref Edible, file.%Edible.decl [concrete = constants.%Edible.type]
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %impl_witness.loc9: <witness> = impl_witness () [concrete = constants.%impl_witness.1bc]
 // CHECK:STDOUT:   %Animal.decl: type = interface_decl @Animal [concrete = constants.%Animal.type] {} {}
 // CHECK:STDOUT:   %Eats.decl: %Eats.type.ba2 = interface_decl @Eats [concrete = constants.%Eats.generic] {
-// CHECK:STDOUT:     %Food.patt.loc9_16.1: type = symbolic_binding_pattern Food, 0 [symbolic = %Food.patt.loc9_16.2 (constants.%Food.patt.e01)]
-// CHECK:STDOUT:     %Food.param_patt: type = value_param_pattern %Food.patt.loc9_16.1, runtime_param<none> [symbolic = %Food.patt.loc9_16.2 (constants.%Food.patt.e01)]
+// CHECK:STDOUT:     %Food.patt.loc12_16.1: type = symbolic_binding_pattern Food, 0 [symbolic = %Food.patt.loc12_16.2 (constants.%Food.patt.e01)]
+// CHECK:STDOUT:     %Food.param_patt: type = value_param_pattern %Food.patt.loc12_16.1, runtime_param<none> [symbolic = %Food.patt.loc12_16.2 (constants.%Food.patt.e01)]
 // CHECK:STDOUT:   } {
 // CHECK:STDOUT:     %Food.param: type = value_param runtime_param<none>
-// CHECK:STDOUT:     %Food.loc9_16.1: type = bind_symbolic_name Food, 0, %Food.param [symbolic = %Food.loc9_16.2 (constants.%Food.8b3)]
+// CHECK:STDOUT:     %Food.loc12_16.1: type = bind_symbolic_name Food, 0, %Food.param [symbolic = %Food.loc12_16.2 (constants.%Food.8b3)]
 // CHECK:STDOUT:   }
-// CHECK:STDOUT:   %Feed.decl: %Feed.type = fn_decl @Feed [concrete = constants.%Feed] {
-// CHECK:STDOUT:     %Food.patt.loc11_9.1: type = symbolic_binding_pattern Food, 0 [symbolic = %Food.patt.loc11_9.2 (constants.%Food.patt.e01)]
-// CHECK:STDOUT:     %Food.param_patt: type = value_param_pattern %Food.patt.loc11_9.1, runtime_param<none> [symbolic = %Food.patt.loc11_9.2 (constants.%Food.patt.e01)]
-// CHECK:STDOUT:     %T.patt.loc11_22.1: @Feed.%Eats.type.loc11_35.2 (%Eats.type.6c0) = symbolic_binding_pattern T, 1 [symbolic = %T.patt.loc11_22.2 (constants.%T.patt.41f)]
-// CHECK:STDOUT:     %T.param_patt: @Feed.%Eats.type.loc11_35.2 (%Eats.type.6c0) = value_param_pattern %T.patt.loc11_22.1, runtime_param<none> [symbolic = %T.patt.loc11_22.2 (constants.%T.patt.41f)]
-// CHECK:STDOUT:     %e.patt: @Feed.%T.as_type.loc11_41.2 (%T.as_type.7b9) = binding_pattern e
-// CHECK:STDOUT:     %e.param_patt: @Feed.%T.as_type.loc11_41.2 (%T.as_type.7b9) = value_param_pattern %e.patt, runtime_param0
-// CHECK:STDOUT:     %food.patt: @Feed.%Food.loc11_9.2 (%Food.8b3) = binding_pattern food
-// CHECK:STDOUT:     %food.param_patt: @Feed.%Food.loc11_9.2 (%Food.8b3) = value_param_pattern %food.patt, runtime_param1
-// CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %Food.param: type = value_param runtime_param<none>
-// CHECK:STDOUT:     %Food.loc11_9.1: type = bind_symbolic_name Food, 0, %Food.param [symbolic = %Food.loc11_9.2 (constants.%Food.8b3)]
-// CHECK:STDOUT:     %T.param: @Feed.%Eats.type.loc11_35.2 (%Eats.type.6c0) = value_param runtime_param<none>
-// CHECK:STDOUT:     %.loc11_35: type = splice_block %Eats.type.loc11_35.1 [symbolic = %Eats.type.loc11_35.2 (constants.%Eats.type.6c0)] {
-// CHECK:STDOUT:       %Eats.ref: %Eats.type.ba2 = name_ref Eats, file.%Eats.decl [concrete = constants.%Eats.generic]
-// CHECK:STDOUT:       %Food.ref.loc11_31: type = name_ref Food, %Food.loc11_9.1 [symbolic = %Food.loc11_9.2 (constants.%Food.8b3)]
-// CHECK:STDOUT:       %Eats.type.loc11_35.1: type = facet_type <@Eats, @Eats(constants.%Food.8b3)> [symbolic = %Eats.type.loc11_35.2 (constants.%Eats.type.6c0)]
-// CHECK:STDOUT:     }
-// CHECK:STDOUT:     %T.loc11_22.1: @Feed.%Eats.type.loc11_35.2 (%Eats.type.6c0) = bind_symbolic_name T, 1, %T.param [symbolic = %T.loc11_22.2 (constants.%T.4eb)]
-// CHECK:STDOUT:     %e.param: @Feed.%T.as_type.loc11_41.2 (%T.as_type.7b9) = value_param runtime_param0
-// CHECK:STDOUT:     %.loc11_41.1: type = splice_block %.loc11_41.2 [symbolic = %T.as_type.loc11_41.2 (constants.%T.as_type.7b9)] {
-// CHECK:STDOUT:       %T.ref: @Feed.%Eats.type.loc11_35.2 (%Eats.type.6c0) = name_ref T, %T.loc11_22.1 [symbolic = %T.loc11_22.2 (constants.%T.4eb)]
-// CHECK:STDOUT:       %T.as_type.loc11_41.1: type = facet_access_type %T.ref [symbolic = %T.as_type.loc11_41.2 (constants.%T.as_type.7b9)]
-// CHECK:STDOUT:       %.loc11_41.2: type = converted %T.ref, %T.as_type.loc11_41.1 [symbolic = %T.as_type.loc11_41.2 (constants.%T.as_type.7b9)]
-// CHECK:STDOUT:     }
-// CHECK:STDOUT:     %e: @Feed.%T.as_type.loc11_41.2 (%T.as_type.7b9) = bind_name e, %e.param
-// CHECK:STDOUT:     %food.param: @Feed.%Food.loc11_9.2 (%Food.8b3) = value_param runtime_param1
-// CHECK:STDOUT:     %Food.ref.loc11_50: type = name_ref Food, %Food.loc11_9.1 [symbolic = %Food.loc11_9.2 (constants.%Food.8b3)]
-// CHECK:STDOUT:     %food: @Feed.%Food.loc11_9.2 (%Food.8b3) = bind_name food, %food.param
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %HandleAnimal.decl: %HandleAnimal.type = fn_decl @HandleAnimal [concrete = constants.%HandleAnimal] {
-// CHECK:STDOUT:     %T.patt.loc22_17.1: %Animal.type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc22_17.2 (constants.%T.patt.a9c)]
-// CHECK:STDOUT:     %T.param_patt: %Animal.type = value_param_pattern %T.patt.loc22_17.1, runtime_param<none> [symbolic = %T.patt.loc22_17.2 (constants.%T.patt.a9c)]
-// CHECK:STDOUT:     %Food.patt.loc22_29.1: type = symbolic_binding_pattern Food, 1 [symbolic = %Food.patt.loc22_29.2 (constants.%Food.patt.7a9)]
-// CHECK:STDOUT:     %Food.param_patt: type = value_param_pattern %Food.patt.loc22_29.1, runtime_param<none> [symbolic = %Food.patt.loc22_29.2 (constants.%Food.patt.7a9)]
-// CHECK:STDOUT:     %a.patt: @HandleAnimal.%T.as_type.loc22_45.2 (%T.as_type.2ad) = binding_pattern a
-// CHECK:STDOUT:     %a.param_patt: @HandleAnimal.%T.as_type.loc22_45.2 (%T.as_type.2ad) = value_param_pattern %a.patt, runtime_param0
-// CHECK:STDOUT:     %food.patt: @HandleAnimal.%Food.loc22_29.2 (%Food.336) = binding_pattern food
-// CHECK:STDOUT:     %food.param_patt: @HandleAnimal.%Food.loc22_29.2 (%Food.336) = value_param_pattern %food.patt, runtime_param1
+// CHECK:STDOUT:   impl_decl @impl.2 [concrete] {
+// CHECK:STDOUT:     %T.patt.loc18_14.1: %Animal.type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc18_14.2 (constants.%T.patt.a9c)]
+// CHECK:STDOUT:     %T.param_patt: %Animal.type = value_param_pattern %T.patt.loc18_14.1, runtime_param<none> [symbolic = %T.patt.loc18_14.2 (constants.%T.patt.a9c)]
+// CHECK:STDOUT:     %U.patt.loc18_26.1: %Edible.type = symbolic_binding_pattern U, 1 [symbolic = %U.patt.loc18_26.2 (constants.%U.patt)]
+// CHECK:STDOUT:     %U.param_patt: %Edible.type = value_param_pattern %U.patt.loc18_26.1, runtime_param<none> [symbolic = %U.patt.loc18_26.2 (constants.%U.patt)]
 // CHECK:STDOUT:   } {
+// CHECK:STDOUT:     %T.ref: %Animal.type = name_ref T, %T.loc18_14.1 [symbolic = %T.loc18_14.2 (constants.%T.fd4)]
+// CHECK:STDOUT:     %T.as_type.loc18_38.1: type = facet_access_type %T.ref [symbolic = %T.as_type.loc18_38.2 (constants.%T.as_type.2ad)]
+// CHECK:STDOUT:     %.loc18_38: type = converted %T.ref, %T.as_type.loc18_38.1 [symbolic = %T.as_type.loc18_38.2 (constants.%T.as_type.2ad)]
+// CHECK:STDOUT:     %Eats.ref: %Eats.type.ba2 = name_ref Eats, file.%Eats.decl [concrete = constants.%Eats.generic]
+// CHECK:STDOUT:     %U.ref: %Edible.type = name_ref U, %U.loc18_26.1 [symbolic = %U.loc18_26.2 (constants.%U)]
+// CHECK:STDOUT:     %U.as_type.loc18_49.1: type = facet_access_type %U.ref [symbolic = %U.as_type.loc18_49.2 (constants.%U.as_type)]
+// CHECK:STDOUT:     %.loc18_49: type = converted %U.ref, %U.as_type.loc18_49.1 [symbolic = %U.as_type.loc18_49.2 (constants.%U.as_type)]
+// CHECK:STDOUT:     %Eats.type.loc18_49.1: type = facet_type <@Eats, @Eats(constants.%U.as_type)> [symbolic = %Eats.type.loc18_49.2 (constants.%Eats.type.f54c3d.1)]
 // CHECK:STDOUT:     %T.param: %Animal.type = value_param runtime_param<none>
 // CHECK:STDOUT:     %Animal.ref: type = name_ref Animal, file.%Animal.decl [concrete = constants.%Animal.type]
-// CHECK:STDOUT:     %T.loc22_17.1: %Animal.type = bind_symbolic_name T, 0, %T.param [symbolic = %T.loc22_17.2 (constants.%T.fd4)]
-// CHECK:STDOUT:     %Food.param: type = value_param runtime_param<none>
-// CHECK:STDOUT:     %Food.loc22_29.1: type = bind_symbolic_name Food, 1, %Food.param [symbolic = %Food.loc22_29.2 (constants.%Food.336)]
-// CHECK:STDOUT:     %a.param: @HandleAnimal.%T.as_type.loc22_45.2 (%T.as_type.2ad) = value_param runtime_param0
-// CHECK:STDOUT:     %.loc22_45.1: type = splice_block %.loc22_45.2 [symbolic = %T.as_type.loc22_45.2 (constants.%T.as_type.2ad)] {
-// CHECK:STDOUT:       %T.ref: %Animal.type = name_ref T, %T.loc22_17.1 [symbolic = %T.loc22_17.2 (constants.%T.fd4)]
-// CHECK:STDOUT:       %T.as_type.loc22_45.1: type = facet_access_type %T.ref [symbolic = %T.as_type.loc22_45.2 (constants.%T.as_type.2ad)]
-// CHECK:STDOUT:       %.loc22_45.2: type = converted %T.ref, %T.as_type.loc22_45.1 [symbolic = %T.as_type.loc22_45.2 (constants.%T.as_type.2ad)]
-// CHECK:STDOUT:     }
-// CHECK:STDOUT:     %a: @HandleAnimal.%T.as_type.loc22_45.2 (%T.as_type.2ad) = bind_name a, %a.param
-// CHECK:STDOUT:     %food.param: @HandleAnimal.%Food.loc22_29.2 (%Food.336) = value_param runtime_param1
-// CHECK:STDOUT:     %Food.ref: type = name_ref Food, %Food.loc22_29.1 [symbolic = %Food.loc22_29.2 (constants.%Food.336)]
-// CHECK:STDOUT:     %food: @HandleAnimal.%Food.loc22_29.2 (%Food.336) = bind_name food, %food.param
+// CHECK:STDOUT:     %T.loc18_14.1: %Animal.type = bind_symbolic_name T, 0, %T.param [symbolic = %T.loc18_14.2 (constants.%T.fd4)]
+// CHECK:STDOUT:     %U.param: %Edible.type = value_param runtime_param<none>
+// CHECK:STDOUT:     %Edible.ref: type = name_ref Edible, file.%Edible.decl [concrete = constants.%Edible.type]
+// CHECK:STDOUT:     %U.loc18_26.1: %Edible.type = bind_symbolic_name U, 1, %U.param [symbolic = %U.loc18_26.2 (constants.%U)]
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %impl_witness.loc18: <witness> = impl_witness (), @impl.2(constants.%T.fd4, constants.%U) [symbolic = @impl.2.%impl_witness (constants.%impl_witness.c7c36b.1)]
 // CHECK:STDOUT:   %Goat.decl: type = class_decl @Goat [concrete = constants.%Goat] {} {}
-// CHECK:STDOUT:   impl_decl @impl.1 [concrete] {} {
+// CHECK:STDOUT:   impl_decl @impl.3 [concrete] {} {
 // CHECK:STDOUT:     %Goat.ref: type = name_ref Goat, file.%Goat.decl [concrete = constants.%Goat]
 // CHECK:STDOUT:     %Animal.ref: type = name_ref Animal, file.%Animal.decl [concrete = constants.%Animal.type]
 // CHECK:STDOUT:   }
-// CHECK:STDOUT:   %impl_witness.loc25: <witness> = impl_witness () [concrete = constants.%impl_witness.1bc]
-// CHECK:STDOUT:   impl_decl @impl.2 [concrete] {
-// CHECK:STDOUT:     %T.patt.loc27_14.1: %Animal.type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc27_14.2 (constants.%T.patt.a9c)]
-// CHECK:STDOUT:     %T.param_patt: %Animal.type = value_param_pattern %T.patt.loc27_14.1, runtime_param<none> [symbolic = %T.patt.loc27_14.2 (constants.%T.patt.a9c)]
+// CHECK:STDOUT:   %impl_witness.loc21: <witness> = impl_witness () [concrete = constants.%impl_witness.1bc]
+// CHECK:STDOUT:   %Feed.decl: %Feed.type = fn_decl @Feed [concrete = constants.%Feed] {
+// CHECK:STDOUT:     %Food.patt.loc23_9.1: %Edible.type = symbolic_binding_pattern Food, 0 [symbolic = %Food.patt.loc23_9.2 (constants.%Food.patt.0b7)]
+// CHECK:STDOUT:     %Food.param_patt: %Edible.type = value_param_pattern %Food.patt.loc23_9.1, runtime_param<none> [symbolic = %Food.patt.loc23_9.2 (constants.%Food.patt.0b7)]
+// CHECK:STDOUT:     %T.patt.loc23_24.1: @Feed.%Eats.type.loc23_37.2 (%Eats.type.b39) = symbolic_binding_pattern T, 1 [symbolic = %T.patt.loc23_24.2 (constants.%T.patt.f09)]
+// CHECK:STDOUT:     %T.param_patt: @Feed.%Eats.type.loc23_37.2 (%Eats.type.b39) = value_param_pattern %T.patt.loc23_24.1, runtime_param<none> [symbolic = %T.patt.loc23_24.2 (constants.%T.patt.f09)]
+// CHECK:STDOUT:     %e.patt: @Feed.%T.as_type.loc23_43.2 (%T.as_type.212) = binding_pattern e
+// CHECK:STDOUT:     %e.param_patt: @Feed.%T.as_type.loc23_43.2 (%T.as_type.212) = value_param_pattern %e.patt, runtime_param0
+// CHECK:STDOUT:     %food.patt: @Feed.%Food.as_type.loc23_37.2 (%Food.as_type.952) = binding_pattern food
+// CHECK:STDOUT:     %food.param_patt: @Feed.%Food.as_type.loc23_37.2 (%Food.as_type.952) = value_param_pattern %food.patt, runtime_param1
+// CHECK:STDOUT:   } {
+// CHECK:STDOUT:     %Food.param: %Edible.type = value_param runtime_param<none>
+// CHECK:STDOUT:     %Edible.ref: type = name_ref Edible, file.%Edible.decl [concrete = constants.%Edible.type]
+// CHECK:STDOUT:     %Food.loc23_9.1: %Edible.type = bind_symbolic_name Food, 0, %Food.param [symbolic = %Food.loc23_9.2 (constants.%Food.9af)]
+// CHECK:STDOUT:     %T.param: @Feed.%Eats.type.loc23_37.2 (%Eats.type.b39) = value_param runtime_param<none>
+// CHECK:STDOUT:     %.loc23_37.1: type = splice_block %Eats.type.loc23_37.1 [symbolic = %Eats.type.loc23_37.2 (constants.%Eats.type.b39)] {
+// CHECK:STDOUT:       %Eats.ref: %Eats.type.ba2 = name_ref Eats, file.%Eats.decl [concrete = constants.%Eats.generic]
+// CHECK:STDOUT:       %Food.ref.loc23_33: %Edible.type = name_ref Food, %Food.loc23_9.1 [symbolic = %Food.loc23_9.2 (constants.%Food.9af)]
+// CHECK:STDOUT:       %Food.as_type.loc23_37.1: type = facet_access_type %Food.ref.loc23_33 [symbolic = %Food.as_type.loc23_37.2 (constants.%Food.as_type.952)]
+// CHECK:STDOUT:       %.loc23_37.2: type = converted %Food.ref.loc23_33, %Food.as_type.loc23_37.1 [symbolic = %Food.as_type.loc23_37.2 (constants.%Food.as_type.952)]
+// CHECK:STDOUT:       %Eats.type.loc23_37.1: type = facet_type <@Eats, @Eats(constants.%Food.as_type.952)> [symbolic = %Eats.type.loc23_37.2 (constants.%Eats.type.b39)]
+// CHECK:STDOUT:     }
+// CHECK:STDOUT:     %T.loc23_24.1: @Feed.%Eats.type.loc23_37.2 (%Eats.type.b39) = bind_symbolic_name T, 1, %T.param [symbolic = %T.loc23_24.2 (constants.%T.223)]
+// CHECK:STDOUT:     %e.param: @Feed.%T.as_type.loc23_43.2 (%T.as_type.212) = value_param runtime_param0
+// CHECK:STDOUT:     %.loc23_43.1: type = splice_block %.loc23_43.2 [symbolic = %T.as_type.loc23_43.2 (constants.%T.as_type.212)] {
+// CHECK:STDOUT:       %T.ref: @Feed.%Eats.type.loc23_37.2 (%Eats.type.b39) = name_ref T, %T.loc23_24.1 [symbolic = %T.loc23_24.2 (constants.%T.223)]
+// CHECK:STDOUT:       %T.as_type.loc23_43.1: type = facet_access_type %T.ref [symbolic = %T.as_type.loc23_43.2 (constants.%T.as_type.212)]
+// CHECK:STDOUT:       %.loc23_43.2: type = converted %T.ref, %T.as_type.loc23_43.1 [symbolic = %T.as_type.loc23_43.2 (constants.%T.as_type.212)]
+// CHECK:STDOUT:     }
+// CHECK:STDOUT:     %e: @Feed.%T.as_type.loc23_43.2 (%T.as_type.212) = bind_name e, %e.param
+// CHECK:STDOUT:     %food.param: @Feed.%Food.as_type.loc23_37.2 (%Food.as_type.952) = value_param runtime_param1
+// CHECK:STDOUT:     %.loc23_52.1: type = splice_block %.loc23_52.2 [symbolic = %Food.as_type.loc23_37.2 (constants.%Food.as_type.952)] {
+// CHECK:STDOUT:       %Food.ref.loc23_52: %Edible.type = name_ref Food, %Food.loc23_9.1 [symbolic = %Food.loc23_9.2 (constants.%Food.9af)]
+// CHECK:STDOUT:       %Food.as_type.loc23_52: type = facet_access_type %Food.ref.loc23_52 [symbolic = %Food.as_type.loc23_37.2 (constants.%Food.as_type.952)]
+// CHECK:STDOUT:       %.loc23_52.2: type = converted %Food.ref.loc23_52, %Food.as_type.loc23_52 [symbolic = %Food.as_type.loc23_37.2 (constants.%Food.as_type.952)]
+// CHECK:STDOUT:     }
+// CHECK:STDOUT:     %food: @Feed.%Food.as_type.loc23_37.2 (%Food.as_type.952) = bind_name food, %food.param
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %HandleAnimal.decl: %HandleAnimal.type = fn_decl @HandleAnimal [concrete = constants.%HandleAnimal] {
+// CHECK:STDOUT:     %T.patt.loc24_17.1: %Animal.type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc24_17.2 (constants.%T.patt.a9c)]
+// CHECK:STDOUT:     %T.param_patt: %Animal.type = value_param_pattern %T.patt.loc24_17.1, runtime_param<none> [symbolic = %T.patt.loc24_17.2 (constants.%T.patt.a9c)]
+// CHECK:STDOUT:     %Food.patt.loc24_29.1: %Edible.type = symbolic_binding_pattern Food, 1 [symbolic = %Food.patt.loc24_29.2 (constants.%Food.patt.551)]
+// CHECK:STDOUT:     %Food.param_patt: %Edible.type = value_param_pattern %Food.patt.loc24_29.1, runtime_param<none> [symbolic = %Food.patt.loc24_29.2 (constants.%Food.patt.551)]
+// CHECK:STDOUT:     %a.patt: @HandleAnimal.%T.as_type.loc24_47.2 (%T.as_type.2ad) = binding_pattern a
+// CHECK:STDOUT:     %a.param_patt: @HandleAnimal.%T.as_type.loc24_47.2 (%T.as_type.2ad) = value_param_pattern %a.patt, runtime_param0
+// CHECK:STDOUT:     %food.patt: @HandleAnimal.%Food.as_type.loc24_56.2 (%Food.as_type.fae) = binding_pattern food
+// CHECK:STDOUT:     %food.param_patt: @HandleAnimal.%Food.as_type.loc24_56.2 (%Food.as_type.fae) = value_param_pattern %food.patt, runtime_param1
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %T.ref: %Animal.type = name_ref T, %T.loc27_14.1 [symbolic = %T.loc27_14.2 (constants.%T.fd4)]
-// CHECK:STDOUT:     %T.as_type.loc27_26.1: type = facet_access_type %T.ref [symbolic = %T.as_type.loc27_26.2 (constants.%T.as_type.2ad)]
-// CHECK:STDOUT:     %.loc27: type = converted %T.ref, %T.as_type.loc27_26.1 [symbolic = %T.as_type.loc27_26.2 (constants.%T.as_type.2ad)]
-// CHECK:STDOUT:     %Eats.ref: %Eats.type.ba2 = name_ref Eats, file.%Eats.decl [concrete = constants.%Eats.generic]
-// CHECK:STDOUT:     %Grass.ref: type = name_ref Grass, file.%Grass.decl [concrete = constants.%Grass]
-// CHECK:STDOUT:     %Eats.type: type = facet_type <@Eats, @Eats(constants.%Grass)> [concrete = constants.%Eats.type.1ae]
 // CHECK:STDOUT:     %T.param: %Animal.type = value_param runtime_param<none>
 // CHECK:STDOUT:     %Animal.ref: type = name_ref Animal, file.%Animal.decl [concrete = constants.%Animal.type]
-// CHECK:STDOUT:     %T.loc27_14.1: %Animal.type = bind_symbolic_name T, 0, %T.param [symbolic = %T.loc27_14.2 (constants.%T.fd4)]
+// CHECK:STDOUT:     %T.loc24_17.1: %Animal.type = bind_symbolic_name T, 0, %T.param [symbolic = %T.loc24_17.2 (constants.%T.fd4)]
+// CHECK:STDOUT:     %Food.param: %Edible.type = value_param runtime_param<none>
+// CHECK:STDOUT:     %Edible.ref: type = name_ref Edible, file.%Edible.decl [concrete = constants.%Edible.type]
+// CHECK:STDOUT:     %Food.loc24_29.1: %Edible.type = bind_symbolic_name Food, 1, %Food.param [symbolic = %Food.loc24_29.2 (constants.%Food.5fe)]
+// CHECK:STDOUT:     %a.param: @HandleAnimal.%T.as_type.loc24_47.2 (%T.as_type.2ad) = value_param runtime_param0
+// CHECK:STDOUT:     %.loc24_47.1: type = splice_block %.loc24_47.2 [symbolic = %T.as_type.loc24_47.2 (constants.%T.as_type.2ad)] {
+// CHECK:STDOUT:       %T.ref: %Animal.type = name_ref T, %T.loc24_17.1 [symbolic = %T.loc24_17.2 (constants.%T.fd4)]
+// CHECK:STDOUT:       %T.as_type.loc24_47.1: type = facet_access_type %T.ref [symbolic = %T.as_type.loc24_47.2 (constants.%T.as_type.2ad)]
+// CHECK:STDOUT:       %.loc24_47.2: type = converted %T.ref, %T.as_type.loc24_47.1 [symbolic = %T.as_type.loc24_47.2 (constants.%T.as_type.2ad)]
+// CHECK:STDOUT:     }
+// CHECK:STDOUT:     %a: @HandleAnimal.%T.as_type.loc24_47.2 (%T.as_type.2ad) = bind_name a, %a.param
+// CHECK:STDOUT:     %food.param: @HandleAnimal.%Food.as_type.loc24_56.2 (%Food.as_type.fae) = value_param runtime_param1
+// CHECK:STDOUT:     %.loc24_56.1: type = splice_block %.loc24_56.2 [symbolic = %Food.as_type.loc24_56.2 (constants.%Food.as_type.fae)] {
+// CHECK:STDOUT:       %Food.ref: %Edible.type = name_ref Food, %Food.loc24_29.1 [symbolic = %Food.loc24_29.2 (constants.%Food.5fe)]
+// CHECK:STDOUT:       %Food.as_type.loc24_56.1: type = facet_access_type %Food.ref [symbolic = %Food.as_type.loc24_56.2 (constants.%Food.as_type.fae)]
+// CHECK:STDOUT:       %.loc24_56.2: type = converted %Food.ref, %Food.as_type.loc24_56.1 [symbolic = %Food.as_type.loc24_56.2 (constants.%Food.as_type.fae)]
+// CHECK:STDOUT:     }
+// CHECK:STDOUT:     %food: @HandleAnimal.%Food.as_type.loc24_56.2 (%Food.as_type.fae) = bind_name food, %food.param
 // CHECK:STDOUT:   }
-// CHECK:STDOUT:   %impl_witness.loc27: <witness> = impl_witness (), @impl.2(constants.%T.fd4) [symbolic = @impl.2.%impl_witness (constants.%impl_witness.8fd)]
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {} {}
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: interface @Edible {
+// CHECK:STDOUT:   %Self: %Edible.type = bind_symbolic_name Self, 0 [symbolic = constants.%Self.9af]
+// CHECK:STDOUT:
+// CHECK:STDOUT: !members:
+// CHECK:STDOUT:   .Self = %Self
+// CHECK:STDOUT:   witness = ()
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: interface @Animal {
 // CHECK:STDOUT:   %Self: %Animal.type = bind_symbolic_name Self, 0 [symbolic = constants.%Self.fd4]
 // CHECK:STDOUT:
@@ -332,12 +376,12 @@ fn F() {
 // CHECK:STDOUT:   witness = ()
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: generic interface @Eats(%Food.loc9_16.1: type) {
-// CHECK:STDOUT:   %Food.loc9_16.2: type = bind_symbolic_name Food, 0 [symbolic = %Food.loc9_16.2 (constants.%Food.8b3)]
-// CHECK:STDOUT:   %Food.patt.loc9_16.2: type = symbolic_binding_pattern Food, 0 [symbolic = %Food.patt.loc9_16.2 (constants.%Food.patt.e01)]
+// CHECK:STDOUT: generic interface @Eats(%Food.loc12_16.1: type) {
+// CHECK:STDOUT:   %Food.loc12_16.2: type = bind_symbolic_name Food, 0 [symbolic = %Food.loc12_16.2 (constants.%Food.8b3)]
+// CHECK:STDOUT:   %Food.patt.loc12_16.2: type = symbolic_binding_pattern Food, 0 [symbolic = %Food.patt.loc12_16.2 (constants.%Food.patt.e01)]
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
-// CHECK:STDOUT:   %Eats.type: type = facet_type <@Eats, @Eats(%Food.loc9_16.2)> [symbolic = %Eats.type (constants.%Eats.type.6c0)]
+// CHECK:STDOUT:   %Eats.type: type = facet_type <@Eats, @Eats(%Food.loc12_16.2)> [symbolic = %Eats.type (constants.%Eats.type.6c0)]
 // CHECK:STDOUT:   %Self.2: %Eats.type.6c0 = bind_symbolic_name Self, 1 [symbolic = %Self.2 (constants.%Self.4eb)]
 // CHECK:STDOUT:
 // CHECK:STDOUT:   interface {
@@ -349,45 +393,35 @@ fn F() {
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: generic interface @ImplicitAs(imports.%Core.import_ref.f6b058.1: type) [from "core.carbon"] {
-// CHECK:STDOUT:   %T: type = bind_symbolic_name T, 0 [symbolic = %T (constants.%T.8b3)]
-// CHECK:STDOUT:   %T.patt: type = symbolic_binding_pattern T, 0 [symbolic = %T.patt (constants.%T.patt.e01)]
-// CHECK:STDOUT:
-// CHECK:STDOUT: !definition:
-// CHECK:STDOUT:   %ImplicitAs.type: type = facet_type <@ImplicitAs, @ImplicitAs(%T)> [symbolic = %ImplicitAs.type (constants.%ImplicitAs.type.d62)]
-// CHECK:STDOUT:   %Self: %ImplicitAs.type.d62 = bind_symbolic_name Self, 1 [symbolic = %Self (constants.%Self.519)]
-// CHECK:STDOUT:   %Convert.type: type = fn_type @Convert, @ImplicitAs(%T) [symbolic = %Convert.type (constants.%Convert.type.275)]
-// CHECK:STDOUT:   %Convert: @ImplicitAs.%Convert.type (%Convert.type.275) = struct_value () [symbolic = %Convert (constants.%Convert.42e)]
-// CHECK:STDOUT:   %ImplicitAs.assoc_type: type = assoc_entity_type @ImplicitAs.%ImplicitAs.type (%ImplicitAs.type.d62) [symbolic = %ImplicitAs.assoc_type (constants.%ImplicitAs.assoc_type.837)]
-// CHECK:STDOUT:   %assoc0: @ImplicitAs.%ImplicitAs.assoc_type (%ImplicitAs.assoc_type.837) = assoc_entity element0, imports.%Core.import_ref.207961.1 [symbolic = %assoc0 (constants.%assoc0.43db8b.1)]
-// CHECK:STDOUT:
-// CHECK:STDOUT:   interface {
-// CHECK:STDOUT:   !members:
-// CHECK:STDOUT:     .Self = imports.%Core.import_ref.ff5
-// CHECK:STDOUT:     .Convert = imports.%Core.import_ref.630
-// CHECK:STDOUT:     witness = (imports.%Core.Convert)
-// CHECK:STDOUT:   }
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: impl @impl.1: %Goat.ref as %Animal.ref {
+// CHECK:STDOUT: impl @impl.1: %Grass.ref as %Edible.ref {
 // CHECK:STDOUT: !members:
-// CHECK:STDOUT:   witness = file.%impl_witness.loc25
+// CHECK:STDOUT:   witness = file.%impl_witness.loc9
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: generic impl @impl.2(%T.loc27_14.1: %Animal.type) {
-// CHECK:STDOUT:   %T.loc27_14.2: %Animal.type = bind_symbolic_name T, 0 [symbolic = %T.loc27_14.2 (constants.%T.fd4)]
-// CHECK:STDOUT:   %T.patt.loc27_14.2: %Animal.type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc27_14.2 (constants.%T.patt.a9c)]
-// CHECK:STDOUT:   %T.as_type.loc27_26.2: type = facet_access_type %T.loc27_14.2 [symbolic = %T.as_type.loc27_26.2 (constants.%T.as_type.2ad)]
-// CHECK:STDOUT:   %impl_witness: <witness> = impl_witness (), @impl.2(%T.loc27_14.2) [symbolic = %impl_witness (constants.%impl_witness.8fd)]
+// CHECK:STDOUT: generic impl @impl.2(%T.loc18_14.1: %Animal.type, %U.loc18_26.1: %Edible.type) {
+// CHECK:STDOUT:   %T.loc18_14.2: %Animal.type = bind_symbolic_name T, 0 [symbolic = %T.loc18_14.2 (constants.%T.fd4)]
+// CHECK:STDOUT:   %T.patt.loc18_14.2: %Animal.type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc18_14.2 (constants.%T.patt.a9c)]
+// CHECK:STDOUT:   %U.loc18_26.2: %Edible.type = bind_symbolic_name U, 1 [symbolic = %U.loc18_26.2 (constants.%U)]
+// CHECK:STDOUT:   %U.patt.loc18_26.2: %Edible.type = symbolic_binding_pattern U, 1 [symbolic = %U.patt.loc18_26.2 (constants.%U.patt)]
+// CHECK:STDOUT:   %T.as_type.loc18_38.2: type = facet_access_type %T.loc18_14.2 [symbolic = %T.as_type.loc18_38.2 (constants.%T.as_type.2ad)]
+// CHECK:STDOUT:   %U.as_type.loc18_49.2: type = facet_access_type %U.loc18_26.2 [symbolic = %U.as_type.loc18_49.2 (constants.%U.as_type)]
+// CHECK:STDOUT:   %Eats.type.loc18_49.2: type = facet_type <@Eats, @Eats(%U.as_type.loc18_49.2)> [symbolic = %Eats.type.loc18_49.2 (constants.%Eats.type.f54c3d.1)]
+// CHECK:STDOUT:   %require_complete: <witness> = require_complete_type @impl.2.%Eats.type.loc18_49.2 (%Eats.type.f54c3d.1) [symbolic = %require_complete (constants.%require_complete.42532a.1)]
+// CHECK:STDOUT:   %impl_witness: <witness> = impl_witness (), @impl.2(%T.loc18_14.2, %U.loc18_26.2) [symbolic = %impl_witness (constants.%impl_witness.c7c36b.1)]
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:
-// CHECK:STDOUT:   impl: %.loc27 as %Eats.type {
+// CHECK:STDOUT:   impl: %.loc18_38 as %Eats.type.loc18_49.1 {
 // CHECK:STDOUT:   !members:
-// CHECK:STDOUT:     witness = file.%impl_witness.loc27
+// CHECK:STDOUT:     witness = file.%impl_witness.loc18
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: impl @impl.3: %Goat.ref as %Animal.ref {
+// CHECK:STDOUT: !members:
+// CHECK:STDOUT:   witness = file.%impl_witness.loc21
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: class @Grass {
 // CHECK:STDOUT:   %complete_type: <witness> = complete_type_witness %empty_struct_type [concrete = constants.%complete_type.357]
 // CHECK:STDOUT:   complete_type_witness = %complete_type
@@ -404,199 +438,246 @@ fn F() {
 // CHECK:STDOUT:   .Self = constants.%Goat
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: generic fn @Feed(%Food.loc11_9.1: type, %T.loc11_22.1: @Feed.%Eats.type.loc11_35.2 (%Eats.type.6c0)) {
-// CHECK:STDOUT:   %Food.loc11_9.2: type = bind_symbolic_name Food, 0 [symbolic = %Food.loc11_9.2 (constants.%Food.8b3)]
-// CHECK:STDOUT:   %Food.patt.loc11_9.2: type = symbolic_binding_pattern Food, 0 [symbolic = %Food.patt.loc11_9.2 (constants.%Food.patt.e01)]
-// CHECK:STDOUT:   %Eats.type.loc11_35.2: type = facet_type <@Eats, @Eats(%Food.loc11_9.2)> [symbolic = %Eats.type.loc11_35.2 (constants.%Eats.type.6c0)]
-// CHECK:STDOUT:   %T.loc11_22.2: %Eats.type.6c0 = bind_symbolic_name T, 1 [symbolic = %T.loc11_22.2 (constants.%T.4eb)]
-// CHECK:STDOUT:   %T.patt.loc11_22.2: %Eats.type.6c0 = symbolic_binding_pattern T, 1 [symbolic = %T.patt.loc11_22.2 (constants.%T.patt.41f)]
-// CHECK:STDOUT:   %T.as_type.loc11_41.2: type = facet_access_type %T.loc11_22.2 [symbolic = %T.as_type.loc11_41.2 (constants.%T.as_type.7b9)]
+// CHECK:STDOUT: generic fn @Feed(%Food.loc23_9.1: %Edible.type, %T.loc23_24.1: @Feed.%Eats.type.loc23_37.2 (%Eats.type.b39)) {
+// CHECK:STDOUT:   %Food.loc23_9.2: %Edible.type = bind_symbolic_name Food, 0 [symbolic = %Food.loc23_9.2 (constants.%Food.9af)]
+// CHECK:STDOUT:   %Food.patt.loc23_9.2: %Edible.type = symbolic_binding_pattern Food, 0 [symbolic = %Food.patt.loc23_9.2 (constants.%Food.patt.0b7)]
+// CHECK:STDOUT:   %Food.as_type.loc23_37.2: type = facet_access_type %Food.loc23_9.2 [symbolic = %Food.as_type.loc23_37.2 (constants.%Food.as_type.952)]
+// CHECK:STDOUT:   %Eats.type.loc23_37.2: type = facet_type <@Eats, @Eats(%Food.as_type.loc23_37.2)> [symbolic = %Eats.type.loc23_37.2 (constants.%Eats.type.b39)]
+// CHECK:STDOUT:   %T.loc23_24.2: %Eats.type.b39 = bind_symbolic_name T, 1 [symbolic = %T.loc23_24.2 (constants.%T.223)]
+// CHECK:STDOUT:   %T.patt.loc23_24.2: %Eats.type.b39 = symbolic_binding_pattern T, 1 [symbolic = %T.patt.loc23_24.2 (constants.%T.patt.f09)]
+// CHECK:STDOUT:   %T.as_type.loc23_43.2: type = facet_access_type %T.loc23_24.2 [symbolic = %T.as_type.loc23_43.2 (constants.%T.as_type.212)]
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
-// CHECK:STDOUT:   %require_complete.loc11_39: <witness> = require_complete_type @Feed.%T.as_type.loc11_41.2 (%T.as_type.7b9) [symbolic = %require_complete.loc11_39 (constants.%require_complete.c74)]
-// CHECK:STDOUT:   %require_complete.loc11_48: <witness> = require_complete_type @Feed.%Food.loc11_9.2 (%Food.8b3) [symbolic = %require_complete.loc11_48 (constants.%require_complete.4ae)]
+// CHECK:STDOUT:   %require_complete.loc23_41: <witness> = require_complete_type @Feed.%T.as_type.loc23_43.2 (%T.as_type.212) [symbolic = %require_complete.loc23_41 (constants.%require_complete.fe6)]
+// CHECK:STDOUT:   %require_complete.loc23_50: <witness> = require_complete_type @Feed.%Food.as_type.loc23_37.2 (%Food.as_type.952) [symbolic = %require_complete.loc23_50 (constants.%require_complete.005)]
 // CHECK:STDOUT:
-// CHECK:STDOUT:   fn[%Food.param_patt: type, %T.param_patt: @Feed.%Eats.type.loc11_35.2 (%Eats.type.6c0)](%e.param_patt: @Feed.%T.as_type.loc11_41.2 (%T.as_type.7b9), %food.param_patt: @Feed.%Food.loc11_9.2 (%Food.8b3)) {
+// CHECK:STDOUT:   fn[%Food.param_patt: %Edible.type, %T.param_patt: @Feed.%Eats.type.loc23_37.2 (%Eats.type.b39)](%e.param_patt: @Feed.%T.as_type.loc23_43.2 (%T.as_type.212), %food.param_patt: @Feed.%Food.as_type.loc23_37.2 (%Food.as_type.952)) {
 // CHECK:STDOUT:   !entry:
 // CHECK:STDOUT:     return
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: generic fn @HandleAnimal(%T.loc22_17.1: %Animal.type, %Food.loc22_29.1: type) {
-// CHECK:STDOUT:   %T.loc22_17.2: %Animal.type = bind_symbolic_name T, 0 [symbolic = %T.loc22_17.2 (constants.%T.fd4)]
-// CHECK:STDOUT:   %T.patt.loc22_17.2: %Animal.type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc22_17.2 (constants.%T.patt.a9c)]
-// CHECK:STDOUT:   %Food.loc22_29.2: type = bind_symbolic_name Food, 1 [symbolic = %Food.loc22_29.2 (constants.%Food.336)]
-// CHECK:STDOUT:   %Food.patt.loc22_29.2: type = symbolic_binding_pattern Food, 1 [symbolic = %Food.patt.loc22_29.2 (constants.%Food.patt.7a9)]
-// CHECK:STDOUT:   %T.as_type.loc22_45.2: type = facet_access_type %T.loc22_17.2 [symbolic = %T.as_type.loc22_45.2 (constants.%T.as_type.2ad)]
+// CHECK:STDOUT: generic fn @HandleAnimal(%T.loc24_17.1: %Animal.type, %Food.loc24_29.1: %Edible.type) {
+// CHECK:STDOUT:   %T.loc24_17.2: %Animal.type = bind_symbolic_name T, 0 [symbolic = %T.loc24_17.2 (constants.%T.fd4)]
+// CHECK:STDOUT:   %T.patt.loc24_17.2: %Animal.type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc24_17.2 (constants.%T.patt.a9c)]
+// CHECK:STDOUT:   %Food.loc24_29.2: %Edible.type = bind_symbolic_name Food, 1 [symbolic = %Food.loc24_29.2 (constants.%Food.5fe)]
+// CHECK:STDOUT:   %Food.patt.loc24_29.2: %Edible.type = symbolic_binding_pattern Food, 1 [symbolic = %Food.patt.loc24_29.2 (constants.%Food.patt.551)]
+// CHECK:STDOUT:   %T.as_type.loc24_47.2: type = facet_access_type %T.loc24_17.2 [symbolic = %T.as_type.loc24_47.2 (constants.%T.as_type.2ad)]
+// CHECK:STDOUT:   %Food.as_type.loc24_56.2: type = facet_access_type %Food.loc24_29.2 [symbolic = %Food.as_type.loc24_56.2 (constants.%Food.as_type.fae)]
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
-// CHECK:STDOUT:   %require_complete.loc22_43: <witness> = require_complete_type @HandleAnimal.%T.as_type.loc22_45.2 (%T.as_type.2ad) [symbolic = %require_complete.loc22_43 (constants.%require_complete.234)]
-// CHECK:STDOUT:   %require_complete.loc22_52: <witness> = require_complete_type @HandleAnimal.%Food.loc22_29.2 (%Food.336) [symbolic = %require_complete.loc22_52 (constants.%require_complete.b54)]
-// CHECK:STDOUT:   %Eats.type: type = facet_type <@Eats, @Eats(%Food.loc22_29.2)> [symbolic = %Eats.type (constants.%Eats.type.3ec)]
-// CHECK:STDOUT:   %require_complete.loc22_74.1: <witness> = require_complete_type @HandleAnimal.%Eats.type (%Eats.type.3ec) [symbolic = %require_complete.loc22_74.1 (constants.%require_complete.588)]
-// CHECK:STDOUT:   %ImplicitAs.type: type = facet_type <@ImplicitAs, @ImplicitAs(%Eats.type)> [symbolic = %ImplicitAs.type (constants.%ImplicitAs.type.dd1)]
-// CHECK:STDOUT:   %require_complete.loc22_74.2: <witness> = require_complete_type @HandleAnimal.%ImplicitAs.type (%ImplicitAs.type.dd1) [symbolic = %require_complete.loc22_74.2 (constants.%require_complete.959)]
-// CHECK:STDOUT:
-// CHECK:STDOUT:   fn[%T.param_patt: %Animal.type, %Food.param_patt: type](%a.param_patt: @HandleAnimal.%T.as_type.loc22_45.2 (%T.as_type.2ad), %food.param_patt: @HandleAnimal.%Food.loc22_29.2 (%Food.336)) {
+// CHECK:STDOUT:   %require_complete.loc24_45: <witness> = require_complete_type @HandleAnimal.%T.as_type.loc24_47.2 (%T.as_type.2ad) [symbolic = %require_complete.loc24_45 (constants.%require_complete.234)]
+// CHECK:STDOUT:   %require_complete.loc24_54: <witness> = require_complete_type @HandleAnimal.%Food.as_type.loc24_56.2 (%Food.as_type.fae) [symbolic = %require_complete.loc24_54 (constants.%require_complete.444)]
+// CHECK:STDOUT:   %Eats.type: type = facet_type <@Eats, @Eats(%Food.as_type.loc24_56.2)> [symbolic = %Eats.type (constants.%Eats.type.f54c3d.2)]
+// CHECK:STDOUT:   %require_complete.loc24_76: <witness> = require_complete_type @HandleAnimal.%Eats.type (%Eats.type.f54c3d.2) [symbolic = %require_complete.loc24_76 (constants.%require_complete.42532a.2)]
+// CHECK:STDOUT:   %impl_witness: <witness> = impl_witness (), @impl.2(%T.loc24_17.2, %Food.loc24_29.2) [symbolic = %impl_witness (constants.%impl_witness.c7c36b.2)]
+// CHECK:STDOUT:   %Eats.facet.loc24_76.2: @HandleAnimal.%Eats.type (%Eats.type.f54c3d.2) = facet_value %T.as_type.loc24_47.2, %impl_witness [symbolic = %Eats.facet.loc24_76.2 (constants.%Eats.facet.b56)]
+// CHECK:STDOUT:   %Feed.specific_fn.loc24_64.2: <specific function> = specific_function constants.%Feed, @Feed(%Food.loc24_29.2, %Eats.facet.loc24_76.2) [symbolic = %Feed.specific_fn.loc24_64.2 (constants.%Feed.specific_fn.f4b)]
+// CHECK:STDOUT:
+// CHECK:STDOUT:   fn[%T.param_patt: %Animal.type, %Food.param_patt: %Edible.type](%a.param_patt: @HandleAnimal.%T.as_type.loc24_47.2 (%T.as_type.2ad), %food.param_patt: @HandleAnimal.%Food.as_type.loc24_56.2 (%Food.as_type.fae)) {
 // CHECK:STDOUT:   !entry:
 // CHECK:STDOUT:     %Feed.ref: %Feed.type = name_ref Feed, file.%Feed.decl [concrete = constants.%Feed]
-// CHECK:STDOUT:     %a.ref: @HandleAnimal.%T.as_type.loc22_45.2 (%T.as_type.2ad) = name_ref a, %a
-// CHECK:STDOUT:     %food.ref: @HandleAnimal.%Food.loc22_29.2 (%Food.336) = name_ref food, %food
-// CHECK:STDOUT:     %.loc22_74: @HandleAnimal.%Eats.type (%Eats.type.3ec) = converted constants.%T.as_type.2ad, <error> [concrete = <error>]
-// CHECK:STDOUT:     %Feed.specific_fn: <specific function> = specific_function %Feed.ref, @Feed(constants.%Food.336, <error>) [concrete = <error>]
-// CHECK:STDOUT:     %Feed.call: init %empty_tuple.type = call %Feed.specific_fn(<error>, %food.ref)
+// CHECK:STDOUT:     %a.ref: @HandleAnimal.%T.as_type.loc24_47.2 (%T.as_type.2ad) = name_ref a, %a
+// CHECK:STDOUT:     %food.ref: @HandleAnimal.%Food.as_type.loc24_56.2 (%Food.as_type.fae) = name_ref food, %food
+// CHECK:STDOUT:     %.loc24_76.1: %Edible.type = converted constants.%Food.as_type.fae, constants.%Food.5fe [symbolic = %Food.loc24_29.2 (constants.%Food.5fe)]
+// CHECK:STDOUT:     %.loc24_76.2: %Edible.type = converted constants.%Food.as_type.fae, constants.%Food.5fe [symbolic = %Food.loc24_29.2 (constants.%Food.5fe)]
+// CHECK:STDOUT:     %.loc24_76.3: %Edible.type = converted constants.%Food.as_type.fae, constants.%Food.5fe [symbolic = %Food.loc24_29.2 (constants.%Food.5fe)]
+// CHECK:STDOUT:     %T.as_type.loc24_76: type = facet_access_type constants.%T.fd4 [symbolic = %T.as_type.loc24_47.2 (constants.%T.as_type.2ad)]
+// CHECK:STDOUT:     %.loc24_76.4: type = converted constants.%T.fd4, %T.as_type.loc24_76 [symbolic = %T.as_type.loc24_47.2 (constants.%T.as_type.2ad)]
+// CHECK:STDOUT:     %.loc24_76.5: %Animal.type = converted %.loc24_76.4, constants.%T.fd4 [symbolic = %T.loc24_17.2 (constants.%T.fd4)]
+// CHECK:STDOUT:     %.loc24_76.6: %Edible.type = converted constants.%Food.as_type.fae, constants.%Food.5fe [symbolic = %Food.loc24_29.2 (constants.%Food.5fe)]
+// CHECK:STDOUT:     %.loc24_76.7: %Animal.type = converted constants.%T.as_type.2ad, constants.%T.fd4 [symbolic = %T.loc24_17.2 (constants.%T.fd4)]
+// CHECK:STDOUT:     %Eats.facet.loc24_76.1: @HandleAnimal.%Eats.type (%Eats.type.f54c3d.2) = facet_value constants.%T.as_type.2ad, constants.%impl_witness.c7c36b.2 [symbolic = %Eats.facet.loc24_76.2 (constants.%Eats.facet.b56)]
+// CHECK:STDOUT:     %.loc24_76.8: @HandleAnimal.%Eats.type (%Eats.type.f54c3d.2) = converted constants.%T.as_type.2ad, %Eats.facet.loc24_76.1 [symbolic = %Eats.facet.loc24_76.2 (constants.%Eats.facet.b56)]
+// CHECK:STDOUT:     %Feed.specific_fn.loc24_64.1: <specific function> = specific_function %Feed.ref, @Feed(constants.%Food.5fe, %.loc24_76.8) [symbolic = %Feed.specific_fn.loc24_64.2 (constants.%Feed.specific_fn.f4b)]
+// CHECK:STDOUT:     %Feed.call: init %empty_tuple.type = call %Feed.specific_fn.loc24_64.1(%a.ref, %food.ref)
 // CHECK:STDOUT:     return
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: generic fn @Convert(imports.%Core.import_ref.f6b058.2: type, imports.%Core.import_ref.ce1: @ImplicitAs.%ImplicitAs.type (%ImplicitAs.type.d62)) [from "core.carbon"] {
-// CHECK:STDOUT:   %T: type = bind_symbolic_name T, 0 [symbolic = %T (constants.%T.8b3)]
-// CHECK:STDOUT:   %ImplicitAs.type: type = facet_type <@ImplicitAs, @ImplicitAs(%T)> [symbolic = %ImplicitAs.type (constants.%ImplicitAs.type.d62)]
-// CHECK:STDOUT:   %Self: %ImplicitAs.type.d62 = bind_symbolic_name Self, 1 [symbolic = %Self (constants.%Self.519)]
-// CHECK:STDOUT:   %Self.as_type: type = facet_access_type %Self [symbolic = %Self.as_type (constants.%Self.as_type)]
-// CHECK:STDOUT:
-// CHECK:STDOUT:   fn[%self.param_patt: @Convert.%Self.as_type (%Self.as_type)]() -> @Convert.%T (%T.8b3);
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
 // CHECK:STDOUT: fn @F() {
 // CHECK:STDOUT: !entry:
 // CHECK:STDOUT:   %HandleAnimal.ref: %HandleAnimal.type = name_ref HandleAnimal, file.%HandleAnimal.decl [concrete = constants.%HandleAnimal]
-// CHECK:STDOUT:   %.loc30_17.1: %empty_struct_type = struct_literal ()
+// CHECK:STDOUT:   %.loc47_17.1: %empty_struct_type = struct_literal ()
 // CHECK:STDOUT:   %Goat.ref: type = name_ref Goat, file.%Goat.decl [concrete = constants.%Goat]
-// CHECK:STDOUT:   %.loc30_17.2: ref %Goat = temporary_storage
-// CHECK:STDOUT:   %.loc30_17.3: init %Goat = class_init (), %.loc30_17.2 [concrete = constants.%Goat.val]
-// CHECK:STDOUT:   %.loc30_17.4: ref %Goat = temporary %.loc30_17.2, %.loc30_17.3
-// CHECK:STDOUT:   %.loc30_19.1: ref %Goat = converted %.loc30_17.1, %.loc30_17.4
-// CHECK:STDOUT:   %.loc30_29.1: %empty_struct_type = struct_literal ()
+// CHECK:STDOUT:   %.loc47_17.2: ref %Goat = temporary_storage
+// CHECK:STDOUT:   %.loc47_17.3: init %Goat = class_init (), %.loc47_17.2 [concrete = constants.%Goat.val]
+// CHECK:STDOUT:   %.loc47_17.4: ref %Goat = temporary %.loc47_17.2, %.loc47_17.3
+// CHECK:STDOUT:   %.loc47_19.1: ref %Goat = converted %.loc47_17.1, %.loc47_17.4
+// CHECK:STDOUT:   %.loc47_29.1: %empty_struct_type = struct_literal ()
 // CHECK:STDOUT:   %Grass.ref: type = name_ref Grass, file.%Grass.decl [concrete = constants.%Grass]
-// CHECK:STDOUT:   %.loc30_29.2: ref %Grass = temporary_storage
-// CHECK:STDOUT:   %.loc30_29.3: init %Grass = class_init (), %.loc30_29.2 [concrete = constants.%Grass.val]
-// CHECK:STDOUT:   %.loc30_29.4: ref %Grass = temporary %.loc30_29.2, %.loc30_29.3
-// CHECK:STDOUT:   %.loc30_31.1: ref %Grass = converted %.loc30_29.1, %.loc30_29.4
-// CHECK:STDOUT:   %Animal.facet.loc30_39.1: %Animal.type = facet_value constants.%Goat, constants.%impl_witness.1bc [concrete = constants.%Animal.facet]
-// CHECK:STDOUT:   %.loc30_39.1: %Animal.type = converted constants.%Goat, %Animal.facet.loc30_39.1 [concrete = constants.%Animal.facet]
-// CHECK:STDOUT:   %Animal.facet.loc30_39.2: %Animal.type = facet_value constants.%Goat, constants.%impl_witness.1bc [concrete = constants.%Animal.facet]
-// CHECK:STDOUT:   %.loc30_39.2: %Animal.type = converted constants.%Goat, %Animal.facet.loc30_39.2 [concrete = constants.%Animal.facet]
-// CHECK:STDOUT:   %HandleAnimal.specific_fn: <specific function> = specific_function %HandleAnimal.ref, @HandleAnimal(constants.%Animal.facet, constants.%Grass) [concrete = constants.%HandleAnimal.specific_fn]
-// CHECK:STDOUT:   %.loc30_19.2: %Goat = bind_value %.loc30_19.1
-// CHECK:STDOUT:   %.loc30_31.2: %Grass = bind_value %.loc30_31.1
-// CHECK:STDOUT:   %HandleAnimal.call: init %empty_tuple.type = call %HandleAnimal.specific_fn(%.loc30_19.2, %.loc30_31.2)
+// CHECK:STDOUT:   %.loc47_29.2: ref %Grass = temporary_storage
+// CHECK:STDOUT:   %.loc47_29.3: init %Grass = class_init (), %.loc47_29.2 [concrete = constants.%Grass.val]
+// CHECK:STDOUT:   %.loc47_29.4: ref %Grass = temporary %.loc47_29.2, %.loc47_29.3
+// CHECK:STDOUT:   %.loc47_31.1: ref %Grass = converted %.loc47_29.1, %.loc47_29.4
+// CHECK:STDOUT:   %Animal.facet.loc47_39.1: %Animal.type = facet_value constants.%Goat, <error> [concrete = <error>]
+// CHECK:STDOUT:   %.loc47_39.1: %Animal.type = converted constants.%Goat, %Animal.facet.loc47_39.1 [concrete = <error>]
+// CHECK:STDOUT:   %Animal.facet.loc47_39.2: %Animal.type = facet_value constants.%Goat, constants.%impl_witness.1bc [concrete = constants.%Animal.facet]
+// CHECK:STDOUT:   %.loc47_39.2: %Animal.type = converted constants.%Goat, %Animal.facet.loc47_39.2 [concrete = constants.%Animal.facet]
+// CHECK:STDOUT:   %Animal.facet.loc47_39.3: %Animal.type = facet_value constants.%Goat, <error> [concrete = <error>]
+// CHECK:STDOUT:   %.loc47_39.3: %Animal.type = converted constants.%Goat, %Animal.facet.loc47_39.3 [concrete = <error>]
+// CHECK:STDOUT:   %Animal.facet.loc47_39.4: %Animal.type = facet_value constants.%Goat, constants.%impl_witness.1bc [concrete = constants.%Animal.facet]
+// CHECK:STDOUT:   %.loc47_39.4: %Animal.type = converted constants.%Goat, %Animal.facet.loc47_39.4 [concrete = constants.%Animal.facet]
+// CHECK:STDOUT:   %Edible.facet.loc47_39.1: %Edible.type = facet_value constants.%Grass, constants.%impl_witness.1bc [concrete = constants.%Edible.facet]
+// CHECK:STDOUT:   %.loc47_39.5: %Edible.type = converted constants.%Grass, %Edible.facet.loc47_39.1 [concrete = constants.%Edible.facet]
+// CHECK:STDOUT:   %Edible.facet.loc47_39.2: %Edible.type = facet_value constants.%Grass, constants.%impl_witness.1bc [concrete = constants.%Edible.facet]
+// CHECK:STDOUT:   %.loc47_39.6: %Edible.type = converted constants.%Grass, %Edible.facet.loc47_39.2 [concrete = constants.%Edible.facet]
+// CHECK:STDOUT:   %HandleAnimal.specific_fn: <specific function> = specific_function %HandleAnimal.ref, @HandleAnimal(constants.%Animal.facet, constants.%Edible.facet) [concrete = constants.%HandleAnimal.specific_fn]
+// CHECK:STDOUT:   %.loc47_19.2: %Goat = bind_value %.loc47_19.1
+// CHECK:STDOUT:   %.loc47_31.2: %Grass = bind_value %.loc47_31.1
+// CHECK:STDOUT:   %HandleAnimal.call: init %empty_tuple.type = call %HandleAnimal.specific_fn(%.loc47_19.2, %.loc47_31.2)
 // CHECK:STDOUT:   return
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: specific @Eats(constants.%Food.8b3) {
-// CHECK:STDOUT:   %Food.loc9_16.2 => constants.%Food.8b3
-// CHECK:STDOUT:   %Food.patt.loc9_16.2 => constants.%Food.8b3
+// CHECK:STDOUT:   %Food.loc12_16.2 => constants.%Food.8b3
+// CHECK:STDOUT:   %Food.patt.loc12_16.2 => constants.%Food.8b3
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: specific @Eats(%Food.loc9_16.2) {}
+// CHECK:STDOUT: specific @Eats(%Food.loc12_16.2) {}
 // CHECK:STDOUT:
-// CHECK:STDOUT: specific @Feed(constants.%Food.8b3, constants.%T.4eb) {
-// CHECK:STDOUT:   %Food.loc11_9.2 => constants.%Food.8b3
-// CHECK:STDOUT:   %Food.patt.loc11_9.2 => constants.%Food.8b3
-// CHECK:STDOUT:   %Eats.type.loc11_35.2 => constants.%Eats.type.6c0
-// CHECK:STDOUT:   %T.loc11_22.2 => constants.%T.4eb
-// CHECK:STDOUT:   %T.patt.loc11_22.2 => constants.%T.4eb
-// CHECK:STDOUT:   %T.as_type.loc11_41.2 => constants.%T.as_type.7b9
-// CHECK:STDOUT: }
+// CHECK:STDOUT: specific @Eats(constants.%U.as_type) {
+// CHECK:STDOUT:   %Food.loc12_16.2 => constants.%U.as_type
+// CHECK:STDOUT:   %Food.patt.loc12_16.2 => constants.%U.as_type
 // CHECK:STDOUT:
-// CHECK:STDOUT: specific @Eats(@Feed.%Food.loc11_9.2) {}
-// CHECK:STDOUT:
-// CHECK:STDOUT: specific @HandleAnimal(constants.%T.fd4, constants.%Food.336) {
-// CHECK:STDOUT:   %T.loc22_17.2 => constants.%T.fd4
-// CHECK:STDOUT:   %T.patt.loc22_17.2 => constants.%T.fd4
-// CHECK:STDOUT:   %Food.loc22_29.2 => constants.%Food.336
-// CHECK:STDOUT:   %Food.patt.loc22_29.2 => constants.%Food.336
-// CHECK:STDOUT:   %T.as_type.loc22_45.2 => constants.%T.as_type.2ad
+// CHECK:STDOUT: !definition:
+// CHECK:STDOUT:   %Eats.type => constants.%Eats.type.f54c3d.1
+// CHECK:STDOUT:   %Self.2 => constants.%Self.4eb
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: specific @Eats(constants.%Food.336) {
-// CHECK:STDOUT:   %Food.loc9_16.2 => constants.%Food.336
-// CHECK:STDOUT:   %Food.patt.loc9_16.2 => constants.%Food.336
+// CHECK:STDOUT: specific @impl.2(constants.%T.fd4, constants.%U) {
+// CHECK:STDOUT:   %T.loc18_14.2 => constants.%T.fd4
+// CHECK:STDOUT:   %T.patt.loc18_14.2 => constants.%T.fd4
+// CHECK:STDOUT:   %U.loc18_26.2 => constants.%U
+// CHECK:STDOUT:   %U.patt.loc18_26.2 => constants.%U
+// CHECK:STDOUT:   %T.as_type.loc18_38.2 => constants.%T.as_type.2ad
+// CHECK:STDOUT:   %U.as_type.loc18_49.2 => constants.%U.as_type
+// CHECK:STDOUT:   %Eats.type.loc18_49.2 => constants.%Eats.type.f54c3d.1
+// CHECK:STDOUT:   %require_complete => constants.%require_complete.42532a.1
+// CHECK:STDOUT:   %impl_witness => constants.%impl_witness.c7c36b.1
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: specific @ImplicitAs(constants.%T.8b3) {
-// CHECK:STDOUT:   %T => constants.%T.8b3
-// CHECK:STDOUT:   %T.patt => constants.%T.8b3
-// CHECK:STDOUT: }
+// CHECK:STDOUT: specific @Eats(@impl.2.%U.as_type.loc18_49.2) {}
 // CHECK:STDOUT:
-// CHECK:STDOUT: specific @ImplicitAs(%T) {}
+// CHECK:STDOUT: specific @impl.2(%T.loc18_14.2, %U.loc18_26.2) {}
 // CHECK:STDOUT:
-// CHECK:STDOUT: specific @ImplicitAs(@Convert.%T) {}
+// CHECK:STDOUT: specific @Eats(constants.%Food.as_type.952) {
+// CHECK:STDOUT:   %Food.loc12_16.2 => constants.%Food.as_type.952
+// CHECK:STDOUT:   %Food.patt.loc12_16.2 => constants.%Food.as_type.952
+// CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: specific @Convert(constants.%T.8b3, constants.%Self.519) {
-// CHECK:STDOUT:   %T => constants.%T.8b3
-// CHECK:STDOUT:   %ImplicitAs.type => constants.%ImplicitAs.type.d62
-// CHECK:STDOUT:   %Self => constants.%Self.519
-// CHECK:STDOUT:   %Self.as_type => constants.%Self.as_type
+// CHECK:STDOUT: specific @Feed(constants.%Food.9af, constants.%T.223) {
+// CHECK:STDOUT:   %Food.loc23_9.2 => constants.%Food.9af
+// CHECK:STDOUT:   %Food.patt.loc23_9.2 => constants.%Food.9af
+// CHECK:STDOUT:   %Food.as_type.loc23_37.2 => constants.%Food.as_type.952
+// CHECK:STDOUT:   %Eats.type.loc23_37.2 => constants.%Eats.type.b39
+// CHECK:STDOUT:   %T.loc23_24.2 => constants.%T.223
+// CHECK:STDOUT:   %T.patt.loc23_24.2 => constants.%T.223
+// CHECK:STDOUT:   %T.as_type.loc23_43.2 => constants.%T.as_type.212
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: specific @ImplicitAs(constants.%Eats.type.3ec) {
-// CHECK:STDOUT:   %T => constants.%Eats.type.3ec
-// CHECK:STDOUT:   %T.patt => constants.%Eats.type.3ec
+// CHECK:STDOUT: specific @Eats(@Feed.%Food.as_type.loc23_37.2) {}
 // CHECK:STDOUT:
-// CHECK:STDOUT: !definition:
-// CHECK:STDOUT:   %ImplicitAs.type => constants.%ImplicitAs.type.dd1
-// CHECK:STDOUT:   %Self => constants.%Self.519
-// CHECK:STDOUT:   %Convert.type => constants.%Convert.type.d69
-// CHECK:STDOUT:   %Convert => constants.%Convert.561
-// CHECK:STDOUT:   %ImplicitAs.assoc_type => constants.%ImplicitAs.assoc_type.163
-// CHECK:STDOUT:   %assoc0 => constants.%assoc0.676
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: specific @Feed(constants.%Food.336, <error>) {
-// CHECK:STDOUT:   %Food.loc11_9.2 => constants.%Food.336
-// CHECK:STDOUT:   %Food.patt.loc11_9.2 => constants.%Food.336
-// CHECK:STDOUT:   %Eats.type.loc11_35.2 => constants.%Eats.type.3ec
-// CHECK:STDOUT:   %T.loc11_22.2 => <error>
-// CHECK:STDOUT:   %T.patt.loc11_22.2 => <error>
-// CHECK:STDOUT:   %T.as_type.loc11_41.2 => <error>
+// CHECK:STDOUT: specific @HandleAnimal(constants.%T.fd4, constants.%Food.5fe) {
+// CHECK:STDOUT:   %T.loc24_17.2 => constants.%T.fd4
+// CHECK:STDOUT:   %T.patt.loc24_17.2 => constants.%T.fd4
+// CHECK:STDOUT:   %Food.loc24_29.2 => constants.%Food.5fe
+// CHECK:STDOUT:   %Food.patt.loc24_29.2 => constants.%Food.5fe
+// CHECK:STDOUT:   %T.as_type.loc24_47.2 => constants.%T.as_type.2ad
+// CHECK:STDOUT:   %Food.as_type.loc24_56.2 => constants.%Food.as_type.fae
+// CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: !definition:
-// CHECK:STDOUT:   %require_complete.loc11_39 => <error>
-// CHECK:STDOUT:   %require_complete.loc11_48 => constants.%require_complete.b54
+// CHECK:STDOUT: specific @Eats(constants.%Food.as_type.fae) {
+// CHECK:STDOUT:   %Food.loc12_16.2 => constants.%Food.as_type.fae
+// CHECK:STDOUT:   %Food.patt.loc12_16.2 => constants.%Food.as_type.fae
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: specific @Eats(@HandleAnimal.%Food.loc22_29.2) {}
+// CHECK:STDOUT: specific @impl.2(constants.%T.fd4, constants.%Food.5fe) {
+// CHECK:STDOUT:   %T.loc18_14.2 => constants.%T.fd4
+// CHECK:STDOUT:   %T.patt.loc18_14.2 => constants.%T.fd4
+// CHECK:STDOUT:   %U.loc18_26.2 => constants.%Food.5fe
+// CHECK:STDOUT:   %U.patt.loc18_26.2 => constants.%Food.5fe
+// CHECK:STDOUT:   %T.as_type.loc18_38.2 => constants.%T.as_type.2ad
+// CHECK:STDOUT:   %U.as_type.loc18_49.2 => constants.%Food.as_type.fae
+// CHECK:STDOUT:   %Eats.type.loc18_49.2 => constants.%Eats.type.f54c3d.2
+// CHECK:STDOUT:   %require_complete => constants.%require_complete.42532a.2
+// CHECK:STDOUT:   %impl_witness => constants.%impl_witness.c7c36b.2
 // CHECK:STDOUT:
-// CHECK:STDOUT: specific @ImplicitAs(@HandleAnimal.%Eats.type) {}
+// CHECK:STDOUT: !definition:
+// CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: specific @Eats(constants.%Grass) {
-// CHECK:STDOUT:   %Food.loc9_16.2 => constants.%Grass
-// CHECK:STDOUT:   %Food.patt.loc9_16.2 => constants.%Grass
+// CHECK:STDOUT: specific @Feed(constants.%Food.5fe, @HandleAnimal.%.loc24_76.8) {
+// CHECK:STDOUT:   %Food.loc23_9.2 => constants.%Food.5fe
+// CHECK:STDOUT:   %Food.patt.loc23_9.2 => constants.%Food.5fe
+// CHECK:STDOUT:   %Food.as_type.loc23_37.2 => constants.%Food.as_type.fae
+// CHECK:STDOUT:   %Eats.type.loc23_37.2 => constants.%Eats.type.f54c3d.2
+// CHECK:STDOUT:   %T.loc23_24.2 => constants.%Eats.facet.b56
+// CHECK:STDOUT:   %T.patt.loc23_24.2 => constants.%Eats.facet.b56
+// CHECK:STDOUT:   %T.as_type.loc23_43.2 => constants.%T.as_type.2ad
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
-// CHECK:STDOUT:   %Eats.type => constants.%Eats.type.1ae
-// CHECK:STDOUT:   %Self.2 => constants.%Self.4eb
+// CHECK:STDOUT:   %require_complete.loc23_41 => constants.%require_complete.234
+// CHECK:STDOUT:   %require_complete.loc23_50 => constants.%require_complete.444
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: specific @impl.2(constants.%T.fd4) {
-// CHECK:STDOUT:   %T.loc27_14.2 => constants.%T.fd4
-// CHECK:STDOUT:   %T.patt.loc27_14.2 => constants.%T.fd4
-// CHECK:STDOUT:   %T.as_type.loc27_26.2 => constants.%T.as_type.2ad
-// CHECK:STDOUT:   %impl_witness => constants.%impl_witness.8fd
+// CHECK:STDOUT: specific @Feed(constants.%Food.5fe, constants.%Eats.facet.b56) {
+// CHECK:STDOUT:   %Food.loc23_9.2 => constants.%Food.5fe
+// CHECK:STDOUT:   %Food.patt.loc23_9.2 => constants.%Food.5fe
+// CHECK:STDOUT:   %Food.as_type.loc23_37.2 => constants.%Food.as_type.fae
+// CHECK:STDOUT:   %Eats.type.loc23_37.2 => constants.%Eats.type.f54c3d.2
+// CHECK:STDOUT:   %T.loc23_24.2 => constants.%Eats.facet.b56
+// CHECK:STDOUT:   %T.patt.loc23_24.2 => constants.%Eats.facet.b56
+// CHECK:STDOUT:   %T.as_type.loc23_43.2 => constants.%T.as_type.2ad
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: specific @impl.2(%T.loc27_14.2) {}
+// CHECK:STDOUT: specific @Eats(@HandleAnimal.%Food.as_type.loc24_56.2) {}
+// CHECK:STDOUT:
+// CHECK:STDOUT: specific @impl.2(@HandleAnimal.%T.loc24_17.2, @HandleAnimal.%Food.loc24_29.2) {}
 // CHECK:STDOUT:
-// CHECK:STDOUT: specific @HandleAnimal(constants.%Animal.facet, constants.%Grass) {
-// CHECK:STDOUT:   %T.loc22_17.2 => constants.%Animal.facet
-// CHECK:STDOUT:   %T.patt.loc22_17.2 => constants.%Animal.facet
-// CHECK:STDOUT:   %Food.loc22_29.2 => constants.%Grass
-// CHECK:STDOUT:   %Food.patt.loc22_29.2 => constants.%Grass
-// CHECK:STDOUT:   %T.as_type.loc22_45.2 => constants.%Goat
+// CHECK:STDOUT: specific @Feed(@HandleAnimal.%Food.loc24_29.2, @HandleAnimal.%Eats.facet.loc24_76.2) {}
+// CHECK:STDOUT:
+// CHECK:STDOUT: specific @HandleAnimal(constants.%Animal.facet, constants.%Edible.facet) {
+// CHECK:STDOUT:   %T.loc24_17.2 => constants.%Animal.facet
+// CHECK:STDOUT:   %T.patt.loc24_17.2 => constants.%Animal.facet
+// CHECK:STDOUT:   %Food.loc24_29.2 => constants.%Edible.facet
+// CHECK:STDOUT:   %Food.patt.loc24_29.2 => constants.%Edible.facet
+// CHECK:STDOUT:   %T.as_type.loc24_47.2 => constants.%Goat
+// CHECK:STDOUT:   %Food.as_type.loc24_56.2 => constants.%Grass
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
-// CHECK:STDOUT:   %require_complete.loc22_43 => constants.%complete_type.357
-// CHECK:STDOUT:   %require_complete.loc22_52 => constants.%complete_type.357
+// CHECK:STDOUT:   %require_complete.loc24_45 => constants.%complete_type.357
+// CHECK:STDOUT:   %require_complete.loc24_54 => constants.%complete_type.357
 // CHECK:STDOUT:   %Eats.type => constants.%Eats.type.1ae
-// CHECK:STDOUT:   %require_complete.loc22_74.1 => constants.%complete_type.004
-// CHECK:STDOUT:   %ImplicitAs.type => constants.%ImplicitAs.type.849
-// CHECK:STDOUT:   %require_complete.loc22_74.2 => constants.%complete_type.eef
+// CHECK:STDOUT:   %require_complete.loc24_76 => constants.%complete_type.004
+// CHECK:STDOUT:   %impl_witness => constants.%impl_witness.15d
+// CHECK:STDOUT:   %Eats.facet.loc24_76.2 => constants.%Eats.facet.c76
+// CHECK:STDOUT:   %Feed.specific_fn.loc24_64.2 => constants.%Feed.specific_fn.e8d
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: specific @ImplicitAs(constants.%Eats.type.1ae) {
-// CHECK:STDOUT:   %T => constants.%Eats.type.1ae
-// CHECK:STDOUT:   %T.patt => constants.%Eats.type.1ae
+// CHECK:STDOUT: specific @Eats(constants.%Grass) {
+// CHECK:STDOUT:   %Food.loc12_16.2 => constants.%Grass
+// CHECK:STDOUT:   %Food.patt.loc12_16.2 => constants.%Grass
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: specific @impl.2(constants.%Animal.facet, constants.%Edible.facet) {
+// CHECK:STDOUT:   %T.loc18_14.2 => constants.%Animal.facet
+// CHECK:STDOUT:   %T.patt.loc18_14.2 => constants.%Animal.facet
+// CHECK:STDOUT:   %U.loc18_26.2 => constants.%Edible.facet
+// CHECK:STDOUT:   %U.patt.loc18_26.2 => constants.%Edible.facet
+// CHECK:STDOUT:   %T.as_type.loc18_38.2 => constants.%Goat
+// CHECK:STDOUT:   %U.as_type.loc18_49.2 => constants.%Grass
+// CHECK:STDOUT:   %Eats.type.loc18_49.2 => constants.%Eats.type.1ae
+// CHECK:STDOUT:   %require_complete => constants.%complete_type.004
+// CHECK:STDOUT:   %impl_witness => constants.%impl_witness.15d
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: specific @Feed(constants.%Edible.facet, constants.%Eats.facet.c76) {
+// CHECK:STDOUT:   %Food.loc23_9.2 => constants.%Edible.facet
+// CHECK:STDOUT:   %Food.patt.loc23_9.2 => constants.%Edible.facet
+// CHECK:STDOUT:   %Food.as_type.loc23_37.2 => constants.%Grass
+// CHECK:STDOUT:   %Eats.type.loc23_37.2 => constants.%Eats.type.1ae
+// CHECK:STDOUT:   %T.loc23_24.2 => constants.%Eats.facet.c76
+// CHECK:STDOUT:   %T.patt.loc23_24.2 => constants.%Eats.facet.c76
+// CHECK:STDOUT:   %T.as_type.loc23_43.2 => constants.%Goat
 // CHECK:STDOUT: }
 // CHECK:STDOUT:

toolchain/check/testdata/impl/no_prelude/impl_cycle.carbon

@@ -177,3 +177,61 @@ fn F() {
   Compare({} as C, {} as D);
   Compare({} as D, {} as C);
 }
+
+// --- deduce_cycle_without_symbolic.carbon
+library "[[@TEST_NAME]]";
+
+interface First {}
+interface Second {}
+
+// When answering a query "does T impl Second", we must avoid trying to deduce
+// parameters for this impl. Not only is doing so unnecessary, it would start a new
+// "does T impl Second" query, leading to a "cycle in impl lookup" error.
+impl forall [T:! Second] T as First {}
+impl forall [T:! type] T as Second {}
+
+class C {}
+
+fn F() {
+  ({} as C) as (C as Second);
+  ({} as C) as (C as First);
+}
+
+// --- fail_todo_deduce_cycle_with_symbolic.carbon
+library "[[@TEST_NAME]]";
+
+interface First(T:! type) {}
+interface Second {}
+
+// When answering a query "does T impl Second", we must avoid trying to deduce
+// parameters for this impl. Not only is doing so unnecessary, it would start a new
+// "does T impl Second" query, leading to a "cycle in impl lookup" error.
+impl forall [T:! Second, U:! type] T as First(U) {}
+impl forall [T:! type] T as Second {}
+
+class C {}
+
+// TODO: See the TODO in impl_lookup.cpp to reject impls where the interface
+// does not match the query.
+fn F() {
+  // CHECK:STDERR: fail_todo_deduce_cycle_with_symbolic.carbon:[[@LINE+7]]:17: error: cycle found in lookup of interface <TODO: interface name> for type `C` [ImplLookupCycle]
+  // CHECK:STDERR:   ({} as C) as (C as Second);
+  // CHECK:STDERR:                 ^~~~~~~~~~~
+  // CHECK:STDERR: fail_todo_deduce_cycle_with_symbolic.carbon:[[@LINE-11]]:1: note: while deducing parameters of generic declared here [DeductionGenericHere]
+  // CHECK:STDERR: impl forall [T:! Second, U:! type] T as First(U) {}
+  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
+  ({} as C) as (C as Second);
+
+  // CHECK:STDERR: fail_todo_deduce_cycle_with_symbolic.carbon:[[@LINE+10]]:17: error: cycle found in lookup of interface <TODO: interface name> for type `C` [ImplLookupCycle]
+  // CHECK:STDERR:   ({} as C) as (C as First(C));
+  // CHECK:STDERR:                 ^~~~~~~~~~~~~
+  // CHECK:STDERR: fail_todo_deduce_cycle_with_symbolic.carbon:[[@LINE-20]]:1: note: while deducing parameters of generic declared here [DeductionGenericHere]
+  // CHECK:STDERR: impl forall [T:! Second, U:! type] T as First(U) {}
+  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: fail_todo_deduce_cycle_with_symbolic.carbon:[[@LINE-23]]:1: note: while deducing parameters of generic declared here [DeductionGenericHere]
+  // CHECK:STDERR: impl forall [T:! Second, U:! type] T as First(U) {}
+  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
+  ({} as C) as (C as First(C));
+}