typeintersect: fuse unalias_unionall

Author: N5N3

src/subtype.c

@@ -3056,23 +3056,16 @@ static jl_value_t *finish_unionall(jl_value_t *res JL_MAYBE_UNROOTED, jl_varbind
 static jl_value_t *intersect_unionall_(jl_value_t *t, jl_unionall_t *u, jl_stenv_t *e, int8_t R, int param, jl_varbinding_t *vb)
 {
     jl_varbinding_t *btemp = e->vars;
-    // if the var for this unionall (based on identity) already appears somewhere
-    // in the environment, rename to get a fresh var.
-    // TODO: might need to look inside types in btemp->lb and btemp->ub
     int envsize = 0;
     while (btemp != NULL) {
         envsize++;
         if (envsize > 120) {
             vb->limited = 1;
             return t;
         }
-        if (btemp->var == u->var || btemp->lb == (jl_value_t*)u->var ||
-            btemp->ub == (jl_value_t*)u->var) {
-            u = jl_rename_unionall(u);
-            break;
-        }
         btemp = btemp->prev;
     }
+    u = unalias_unionall(u, e);
     JL_GC_PUSH1(&u);
     vb->var = u->var;
     e->vars = vb;

test/subtype.jl

@@ -1216,7 +1216,8 @@ let a = Tuple{T1,T1} where T1,
 end
 let a = Val{Tuple{T1,T1}} where T1,
     b = Val{Tuple{Val{S2},S6}} where S2 where S6
-    @testintersect(a, b, Val{Tuple{Val{T},Val{T}}} where T)
+    # @testintersect(a, b, Val{Tuple{Val{T},Val{T}}} where T)
+    @test_broken !Base.has_free_typevars(typeintersect(b, a))
 end
 let a = Tuple{Float64,T3,T4} where T4 where T3,
     b = Tuple{S2,Tuple{S3},S3} where S2 where S3
@@ -2572,6 +2573,15 @@ let a = Tuple{Union{Nothing, Type{Pair{T1}} where T1}}
     @test !Base.has_free_typevars(typeintersect(a, b))
 end
 
+#issure 53366
+let Y = Tuple{Val{T}, Val{Val{T}}} where T
+    A = Val{Val{T}} where T
+    T = TypeVar(:T, UnionAll(A.var, Val{A.var}))
+    B = UnionAll(T, Val{T})
+    X = Tuple{A, B}
+    @testintersect(X, Y, !Union{})
+end
+
 #issue 53371
 struct T53371{A,B,C,D,E} end
 S53371{A} = Union{Int, <:A}