fix function syntax using both where and return type

also fix #20172

src/ast.scm

@@ -5,6 +5,16 @@
 (define (deparse-arglist l (sep ",")) (string.join (map deparse l) sep))
 
 (define (deparse e)
+  (define (block-stmts e)
+    (if (and (pair? e) (eq? (car e) 'block))
+        (cdr e)
+        (list e)))
+  (define (deparse-block head lst)
+    (string head "\n"
+            (string.join (map (lambda (ex) (string "    " (deparse ex)))
+                              lst)
+                         "\n")
+            "\nend"))
   (cond ((or (symbol? e) (number? e)) (string e))
         ((string? e) (print-to-string e))
         ((eq? e #t) "true")
@@ -67,17 +77,16 @@
                             (string "# line " (cadr e))
                             (string "# " (caddr e) ", line " (cadr e))))
                 ((block)
-                 (string "begin\n"
-                         (string.join (map (lambda (ex) (string "    " (deparse ex)))
-                                           (cdr e))
-                                      "\n")
-                         "\nend"))
+                 (deparse-block "begin" (cdr e)))
                 ((comprehension)
                  (string "[ " (deparse (cadr e)) " for " (deparse-arglist (cddr e) ", ") " ]"))
                 ((generator)
                  (string "(" (deparse (cadr e)) " for " (deparse-arglist (cddr e) ", ") ")"))
                 ((where)
                  (string (deparse (cadr e)) " where " (deparse (caddr e))))
+                ((function for while)
+                 (deparse-block (string (car e) " " (deparse (cadr e)))
+                                (block-stmts (caddr e))))
                 (else
                  (string e))))))
 

src/julia-syntax.scm

@@ -954,7 +954,7 @@
          (where (if (and (pair? name) (eq? (car name) 'where))
                     (let ((w (flatten-where-expr name)))
                       (begin0 (cddr w)
-                              (if (not (and (pair? (cadr w)) (eq? (caadr w) 'call)))
+                              (if (not (and (pair? (cadr w)) (memq (caadr w) '(call |::|))))
                                   (error (string "invalid assignment location \"" (deparse name) "\"")))
                               (set! name (cadr w))))
                     #f))
@@ -1000,7 +1000,8 @@
                                #f name)))
              (expand-forms
               (method-def-expr name sparams argl (caddr e) isstaged rett))))
-          (else e))))
+          (else
+           (error (string "invalid assignment location \"" (deparse name) "\""))))))
 
 ;; handle ( )->( ) function expressions. blocks `(a;b=1)` on the left need to be
 ;; converted to argument lists with kwargs.
@@ -3553,7 +3554,7 @@ f(x) = yt(x)
             ((...)
              (error "\"...\" expression outside call"))
             (else
-             (error (string "unhandled expr " e))))))
+             (error (string "invalid syntax " (deparse e)))))))
     ;; introduce new slots for assigned arguments
     (for-each (lambda (v)
                 (if (vinfo:asgn v)

test/core.jl

@@ -4179,6 +4179,13 @@ function f17613_2(x)::Float64
 end
 @test isa(f17613_2(1), Float64)
 
+# return type decl with `where`
+function where1090(x::Array{T})::T where T<:Real
+    return x[1] + 2.0
+end
+@test where1090([4]) === 6
+@test_throws MethodError where1090(String[])
+
 type A1090 end
 Base.convert(::Type{Int}, ::A1090) = "hey"
 f1090()::Int = A1090()