fixes for some tests

The `identifier-binding` function is now senstive to the "macro
introduction" scope that's on an indentifier provided to a currently
expanding macro. Unit tests for TR need to use
`syntax-local-intorduce` to remove it, in the same way that `tc-setup`
already does.

Also, recognize a class expansion when it's wrapped with
`#%expression`, since `class` now expands that way sometimes.

typed-racket-lib/typed-racket/typecheck/check-class-unit.rkt

@@ -153,8 +153,8 @@
             (let-values ([(field-name:id) accessor-or-mutator] ...)
               :make-methods-body))))
 
-(define-syntax-class class-expansion
-  #:literals (#%plain-app quote)
+(define-syntax-class core-class-expansion
+  #:literals (let-values letrec-syntaxes+values #%plain-app quote)
   #:attributes (superclass-expr
                 make-methods
                 initializer-body
@@ -170,6 +170,16 @@
             (quote :boolean)
             (quote #f))))
 
+(define-syntax-class class-expansion
+  #:literals (#%expression)
+  #:attributes (superclass-expr
+                make-methods
+                initializer-body
+                initializer-self-id
+                initializer-args-id)
+  (pattern :core-class-expansion)
+  (pattern (#%expression :core-class-expansion)))
+
 ;; This is similar to `type-declaration` from "internal-forms.rkt", but
 ;; the expansion is slightly different in a class so we use this instead.
 (define-syntax-class class-type-declaration

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

@@ -51,7 +51,7 @@
   ;; tr-expand: syntax? -> syntax?
   ;; Expands out a form and annotates it with necesarry TR machinery.
   (define (tr-expand stx)
-    (define expanded-stx (local-expand stx 'expression '()))
+    (define expanded-stx (syntax-local-introduce (local-expand stx 'expression '())))
     (find-mutated-vars expanded-stx mvar-env)
     expanded-stx)