Also check eqc in intersect_typevar (fixes #11367)

Author: timholy

src/jltypes.c

@@ -754,6 +754,20 @@ static jl_value_t *intersect_typevar(jl_tvar_t *a, jl_value_t *b,
                     break;
                 }
             }
+            for(i=0; i < eqc->n; i+=2) {
+                if (eqc->data[i] == b && !jl_is_typevar(eqc->data[i+1])) {
+                    if (jl_types_equal((jl_value_t*)a, eqc->data[i+1])) {
+                        JL_GC_POP();
+                        return (jl_value_t*)a;
+                    }
+                    jl_value_t *ti = jl_type_intersection((jl_value_t*)a, eqc->data[i+1]);
+                    if (ti == (jl_value_t*)jl_bottom_type) {
+                        JL_GC_POP();
+                        return ti;
+                    }
+                    break;
+                }
+            }
         }
         extend((jl_value_t*)a, b, penv);
         if (jl_is_typevar(b)) {

test/core.jl

@@ -2847,3 +2847,9 @@ type B11136 end
 let T = TypeVar(:T, true), TB = TypeVar(:T, B11136, true)
     testintersect(Tuple{T, T}, Tuple{A11136, TB}, Bottom)
 end
+
+# issue #11367
+abstract Foo11367
+let T1 = TypeVar(:T1, true), T2 = TypeVar(:T2, Foo11367, true)
+    testintersect(Tuple{T1, T1}, Tuple{Type{BigInt}, T2}, Bottom)
+end