Make heterogenous vector typechecking not double typecheck the arguments.

pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/typecheck/tc-app/tc-app-hetero.rkt

@@ -109,14 +109,18 @@
                 (tc-expr/check e (ret t))
                 t)))]
       [(tc-result1: (app resolve (HeterogeneousVector: ts)))
-       (unless (= (length ts) (syntax-length #'(args ...)))
-         (tc-error/expr "expected vector with ~a elements, but got ~a"
-                        (length ts)
-                        (make-HeterogeneousVector (stx-map tc-expr/t #'(args ...)))))
-       (for ([e (in-syntax #'(args ...))]
+       (cond
+         [(= (length ts) (syntax-length #'(args ...)))
+          (ret
+            (make-HeterogeneousVector
+              (for/list ([e (in-syntax #'(args ...))]
                          [t (in-list ts)])
-         (tc-expr/check e (ret t)))
-       expected]
+                (tc-expr/check/t e (ret t))))
+            -true-filter)]
+         [else
+          (tc-error/expr #:return (ret -Bottom)
+            "expected vector with ~a elements, but got ~a"
+            (length ts) (make-HeterogeneousVector (stx-map tc-expr/t #'(args ...))))])]
       ;; If the expected type is a union, then we examine just the parts
       ;; of the union that are vectors.  If there's only one of those,
       ;; we re-run this whole algorithm with that.  Otherwise, we treat

pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/fail/heterogeneous-vector-bad-ann.rkt

@@ -0,0 +1,5 @@
+#;
+(exn-pred 2)
+#lang typed/racket
+
+(ann (vector (ann 1 Symbol)) (Vector Number Symbol))

pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/unit-tests/typecheck-tests.rkt

@@ -2593,6 +2593,11 @@
        [tc-e (reverse (list 'x 'y))
              #:ret (ret (-Tuple (list (-val 'y) (-val 'x))))
              #:expected (ret (-Tuple (list (-val 'y) (-val 'x))) -no-filter -no-obj)]
+
+       [tc-err (vector 1 2)
+         #:ret (ret (make-HeterogeneousVector (list -Byte -Byte)) -false-filter -empty-obj)
+         #:expected (ret (make-HeterogeneousVector (list -Byte -Byte)) -false-filter -no-obj)]
+
         )
   (test-suite
    "tc-literal tests"