Revert "Move early needs_subst bailout to _after_ linting."

This reverts commit 99492e4.

Author: RalfJung

src/librustc_mir/transform/const_prop.rs

@@ -604,6 +604,11 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
             return None;
         }
 
+        // FIXME we need to revisit this for #67176
+        if rvalue.needs_subst() {
+            return None;
+        }
+
         // Perform any special handling for specific Rvalue types.
         // Generally, checks here fall into one of two categories:
         //   1. Additional checking to provide useful lints to the user
@@ -644,11 +649,6 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
             _ => {}
         }
 
-        // FIXME we need to revisit this for #67176
-        if rvalue.needs_subst() {
-            return None;
-        }
-
         self.use_ecx(|this| {
             trace!("calling eval_rvalue_into_place(rvalue = {:?}, place = {:?})", rvalue, place);
             this.ecx.eval_rvalue_into_place(rvalue, place)?;