fix #37890, fix new error checks with varargs

src/julia-syntax.scm

@@ -746,13 +746,17 @@
  ,@locs
  (call (curly ,name ,@params) ,@field-names)))))
 
+(define (num-non-varargs args)
+ (count (lambda (a) (not (vararg? a))) args))
+
 (define (new-call Tname type-params sparams params args field-names field-types)
  (if (any kwarg? args)
  (error "\"new\" does not accept keyword arguments"))
- (if (length> params (length type-params))
- (error "too few type parameters specified in \"new{...}\""))
- (if (length> type-params (length params))
- (error "too many type parameters specified in \"new{...}\""))
+ (let ((nnv (num-non-varargs type-params)))
+ (if (and (not (any vararg? type-params)) (length> params nnv))
+ (error "too few type parameters specified in \"new{...}\""))
+ (if (> nnv (length params))
+ (error "too many type parameters specified in \"new{...}\"")))
  (let* ((Texpr (if (null? type-params)
  `(outerref ,Tname)
  `(curly (outerref ,Tname)
@@ -767,7 +771,7 @@
  ; local variable (currently just handles sparam) for the bijection of params to type-params
  `(call (core fieldtype) ,tn ,(+ fld 1)))
  ,val)))))
- (cond ((length> (filter (lambda (a) (not (vararg? a))) args) (length field-names))
+ (cond ((> (num-non-varargs args) (length field-names))
  `(call (core throw) (call (top ArgumentError)
  ,(string "new: too many arguments (expected " (length field-names) ")"))))
  ((any vararg? args)

test/syntax.jl

@@ -2345,3 +2345,20 @@ end
 
 # issue #37656
 @test :(if true 'a' else 1 end) == Expr(:if, true, quote 'a' end, quote 1 end)
+
+# issue #37890
+struct A37890{A, B}
+ a
+ b
+ A37890(args::Tuple) = return new{typeof.(args)...}(args...)
+end
+@test A37890((1, "")) isa A37890{Int, String}
+@test_throws ErrorException A37890((1,1,1))
+@test_throws TypeError A37890((1,))
+
+struct B37890{A, B}
+ a
+ b
+ B37890(a, b) = new{Int, ()..., Int8}(a, b)
+end
+@test B37890(1.0, 2.0f0) isa B37890{Int, Int8}