Add stubs for fold_const

Co-Authored-By: Gabriel Smith <[email protected]>

Author: varkor

src/librustc/infer/freshen.rs

@@ -192,4 +192,8 @@ impl<'a, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for TypeFreshener<'a, 'gcx, 'tcx> {
             ty::Bound(..) => bug!("unexpected type {:?}", t),
         }
     }
+
+    fn fold_const(&mut self, ct: &'tcx ty::LazyConst<'tcx>) -> &'tcx ty::LazyConst<'tcx> {
+        ct // FIXME(const_generics)
+    }
 }

src/librustc/infer/fudge.rs

@@ -174,4 +174,8 @@ impl<'a, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for InferenceFudger<'a, 'gcx, 'tcx>
         }
         r
     }
+
+    fn fold_const(&mut self, ct: &'tcx ty::LazyConst<'tcx>) -> &'tcx ty::LazyConst<'tcx> {
+        ct // FIXME(const_generics)
+    }
 }

src/librustc/infer/opaque_types/mod.rs

@@ -659,6 +659,10 @@ impl<'cx, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for ReverseMapper<'cx, 'gcx, 'tcx>
             _ => ty.super_fold_with(self),
         }
     }
+
+    fn fold_const(&mut self, ct: &'tcx ty::LazyConst<'tcx>) -> &'tcx ty::LazyConst<'tcx> {
+        ct // FIXME(const_generics)
+    }
 }
 
 struct Instantiator<'a, 'gcx: 'tcx, 'tcx: 'a> {

src/librustc/ty/fold.rs

@@ -505,6 +505,10 @@ impl<'a, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for BoundVarReplacer<'a, 'gcx, 'tcx>
             _ => r
         }
     }
+
+    fn fold_const(&mut self, ct: &'tcx ty::LazyConst<'tcx>) -> &'tcx ty::LazyConst<'tcx> {
+        ct // FIXME(const_generics)
+    }
 }
 
 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
@@ -740,6 +744,10 @@ impl TypeFolder<'gcx, 'tcx> for Shifter<'a, 'gcx, 'tcx> {
             _ => ty.super_fold_with(self),
         }
     }
+
+    fn fold_const(&mut self, ct: &'tcx ty::LazyConst<'tcx>) -> &'tcx ty::LazyConst<'tcx> {
+        ct // FIXME(const_generics)
+    }
 }
 
 pub fn shift_region<'a, 'gcx, 'tcx>(