adjust and/c so that it mentions the particular predicate (flat contract) that failed in the case that all its arguments are flat contracts

collects/racket/contract/private/guts.rkt

@@ -322,6 +322,24 @@
           ([p (in-list (cdr projs))])
           (λ (v) (p (proj v))))))))
 
+(define (first-order-and-proj ctc)
+  (λ (blame)
+    (λ (val)
+      (let loop ([predicates (first-order-and/c-predicates ctc)]
+                 [ctcs (base-and/c-ctcs ctc)])
+          (cond
+            [(null? predicates) val]
+            [else
+             (if ((car predicates) val)
+                 (loop (cdr predicates) (cdr ctcs))
+                 (raise-blame-error
+                  blame
+                  val
+                  "expected <~s>, given ~a, which isn't ~s"
+                  (contract-name ctc)
+                  val
+                  (contract-name (car ctcs))))])))))
+
 (define (and-stronger? this that)
   (and (base-and/c? that)
        (let ([this-ctcs (base-and/c-ctcs this)]
@@ -332,6 +350,13 @@
                       that-ctcs)))))
 
 (define-struct base-and/c (ctcs))
+(define-struct (first-order-and/c base-and/c) (predicates)
+  #:property prop:flat-contract
+  (build-flat-contract-property
+   #:projection first-order-and-proj
+   #:name and-name
+   #:first-order and-first-order
+   #:stronger and-stronger?))
 (define-struct (chaperone-and/c base-and/c) ()
   #:property prop:chaperone-contract
   (build-chaperone-contract-property
@@ -347,15 +372,14 @@
    #:first-order and-first-order
    #:stronger and-stronger?))
 
+
 (define/subexpression-pos-prop (and/c . raw-fs)
   (let ([contracts (coerce-contracts 'and/c raw-fs)])
     (cond
       [(null? contracts) any/c]
       [(andmap flat-contract? contracts)
        (let ([preds (map flat-contract-predicate contracts)])
-         (flat-named-contract
-          (apply build-compound-type-name 'and/c contracts)
-          (λ (x) (for/and ([pred (in-list preds)]) (pred x)))))]
+         (make-first-order-and/c contracts preds))]
       [(andmap chaperone-contract? contracts)
        (make-chaperone-and/c contracts)]
       [else (make-impersonator-and/c contracts)])))

collects/tests/racket/contract-test.rktl

@@ -3533,6 +3533,18 @@
       (reverse x))
    '(3 1 2 4))
   
+  (test/spec-passed/result
+   'and/c-isnt
+   '(and (regexp-match #rx"isn't even?"
+                       (with-handlers ((exn:fail? exn-message))
+                         (contract (and/c integer? even? positive?)
+                                   -3
+                                   'pos
+                                   'neg)
+                         "not the error!"))
+         #t)
+   #t)
+  
   (test/spec-passed
    'contract-flat1 
    '(contract not #f 'pos 'neg))