Avoid trying to normalize unnormalizable types

diff --git a/compiler/rustc_middle/src/ty/sty.rs b/compiler/rustc_middle/src/ty/sty.rs
index 25b8d01918b2180afba701921d61db014909aaf5..38f924eaf4d2a802a0fe7b04e29086648840a535 100644 (file)
--- a/compiler/rustc_middle/src/ty/sty.rs
+++ b/compiler/rustc_middle/src/ty/sty.rs
@@ -982,7 +982,10 @@ impl<'tcx, T> Binder<'tcx, T>
     /// different binding level.
     #[track_caller]
     pub fn dummy(value: T) -> Binder<'tcx, T> {
-        assert!(!value.has_escaping_bound_vars());
+        assert!(
+            !value.has_escaping_bound_vars(),
+            "`{value:?}` has escaping bound vars, so it cannot be wrapped in a dummy binder."
+        );
         Binder(value, ty::List::empty())
     }
 

diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index 89c8abe4f99ee0da4867e23a99c89e320f51c512..c6ab8e1a83bef786d0167c204065dccb6275951b 100644 (file)
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -22,6 +22,7 @@
 use rustc_middle::middle::resolve_lifetime as rl;
 use rustc_middle::ty::fold::TypeFolder;
 use rustc_middle::ty::InternalSubsts;
+use rustc_middle::ty::TypeVisitable;
 use rustc_middle::ty::{self, AdtKind, DefIdTree, EarlyBinder, Ty, TyCtxt};
 use rustc_middle::{bug, span_bug};
 use rustc_span::hygiene::{AstPass, MacroKind};
@@ -1459,8 +1460,11 @@ fn clean_qpath<'tcx>(hir_ty: &hir::Ty<'tcx>, cx: &mut DocContext<'tcx>) -> Type
         hir::QPath::Resolved(Some(qself), p) => {
             // Try to normalize `<X as Y>::T` to a type
             let ty = hir_ty_to_ty(cx.tcx, hir_ty);
-            if let Some(normalized_value) = normalize(cx, ty::Binder::dummy(ty)) {
-                return clean_middle_ty(normalized_value, cx, None);
+            // `hir_to_ty` can return projection types with escaping vars for GATs, e.g. `<() as Trait>::Gat<'_>`
+            if !ty.has_escaping_bound_vars() {
+                if let Some(normalized_value) = normalize(cx, ty::Binder::dummy(ty)) {
+                    return clean_middle_ty(normalized_value, cx, None);
+                }
             }
 
             let trait_segments = &p.segments[..p.segments.len() - 1];