remove sizedness_fast_path in fulfill.rs

It solves #141806.
sizedness_fast_path in FulfillProcessor.process_obligation
causes the panic if the Sized type doesn't exist.

Signed-off-by: Shunpoco <[email protected]>

Author: Shunpoco

compiler/rustc_trait_selection/src/traits/fulfill.rs

@@ -30,10 +30,10 @@ use super::{
 use crate::error_reporting::InferCtxtErrorExt;
 use crate::infer::{InferCtxt, TyOrConstInferVar};
 use crate::solve::StalledOnCoroutines;
+use crate::traits::EvaluateConstErr;
 use crate::traits::normalize::normalize_with_depth_to;
 use crate::traits::project::{PolyProjectionObligation, ProjectionCacheKeyExt as _};
 use crate::traits::query::evaluate_obligation::InferCtxtExt;
-use crate::traits::{EvaluateConstErr, sizedness_fast_path};
 
 pub(crate) type PendingPredicateObligations<'tcx> = ThinVec<PendingPredicateObligation<'tcx>>;
 
@@ -363,10 +363,6 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
 
         let infcx = self.selcx.infcx;
 
-        if sizedness_fast_path(infcx.tcx, obligation.predicate, obligation.param_env) {
-            return ProcessResult::Changed(thin_vec![]);
-        }
-
         if obligation.predicate.has_aliases() {
             let mut obligations = PredicateObligations::new();
             let predicate = normalize_with_depth_to(

tests/ui/sized/missing-sized-not-panic.rs

@@ -0,0 +1,10 @@
+// ICE-141806
+trait Trait<T> {}
+fn func(x: *const dyn Trait<()>)
+where
+    Missing: Sized, //~ ERROR E0412
+{
+    let _x: *const dyn Trait<u8> = x as _;
+}
+
+fn main() {}

tests/ui/sized/missing-sized-not-panic.stderr

@@ -0,0 +1,9 @@
+error[E0412]: cannot find type `Missing` in this scope
+  --> $DIR/missing-sized-not-panic.rs:5:5
+   |
+LL |     Missing: Sized,
+   |     ^^^^^^^ not found in this scope
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0412`.