anon-const, do not add in-band lifetimes

Author: lcnr

compiler/rustc_ast_lowering/src/lib.rs

@@ -2345,12 +2345,14 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 // but as we already mention the parent generics this is not actually needed.
                 //
                 // Consider only adding explicit higher ranked lifetimes here.
+
+                // We only need `in_scope_lifetimes` because all in-band lifetimes are
+                // added to the generics of the parent.
                 let lifetime_params: Vec<(Span, ParamName)> = this
                     .in_scope_lifetimes
                     .iter()
                     .cloned()
                     .map(|name| (name.ident().span, name))
-                    .chain(this.lifetimes_to_define.iter().cloned())
                     .collect();
 
                 let generic_params =

src/test/ui/const-generics/binders/arr-in-arr.rs

@@ -7,7 +7,7 @@ struct Bar<'a, 'b, 'c>(&'a (), &'b (), &'c ());
 trait Baz<'a, 'b, T> {}
 
 struct Foo<'a>(&'a ()) where for<'b> [u8; {
-    let _: Box<dyn for<'c> Baz<'a, 'b, [u8; { 
+    let _: Box<dyn for<'c> Baz<'a, 'b, [u8; {
         let _: Bar<'a, 'b, 'c>;
         3
     }]>>;

src/test/ui/const-generics/binders/const-eval.rs

@@ -14,4 +14,4 @@ fn test<T>() {
 
 fn main() {
     test::<u32>();
-}
+}

src/test/ui/const-generics/binders/in-band-lt.rs

@@ -0,0 +1,15 @@
+// run-pass
+#![feature(in_band_lifetimes, const_generics)]
+#![allow(incomplete_features)]
+
+struct Foo<T>(T);
+
+impl Foo<[u8; { let _: &'a (); 3 }]> {
+    fn test() -> Self {
+        Foo([0; 3])
+    }
+}
+
+fn main() {
+    assert_eq!(Foo::test().0, [0; 3]);
+}