un-deprecate (;) and make it parse to an empty named tuple

fixes #30115

NEWS.md

@@ -32,6 +32,8 @@ Language changes
   (in addition to the one that enters the help mode) to see the full
   docstring. ([#25930])
 
+* The syntax `(;)` (which was deprecated in v1.4) now creates an empty named tuple ([#30115]).
+
 Multi-threading changes
 -----------------------
 

src/julia-parser.scm

@@ -1921,9 +1921,7 @@
                               (and (null? first) (null? blk)
                                    ;; all semicolons inside ()
                                    (if (length= (car args) 1)
-                                       (begin (parser-depwarn s "(;)" "begin end")
-                                              ;; should eventually be (tuple (parameters))
-                                              `(block))
+                                       `(tuple (parameters))
                                        `(block)))))))
           (and (null? first) (null? args) (not comma?)
                (error "unreachable"))

test/syntax.jl

@@ -171,7 +171,7 @@ macro test999_str(args...); args; end
 
 # blocks vs. tuples
 @test Meta.parse("()") == Expr(:tuple)
-@test_skip Meta.parse("(;)") == Expr(:tuple, Expr(:parameters))
+@test Meta.parse("(;)") == Expr(:tuple, Expr(:parameters))
 @test Meta.parse("(;;;;)") == Expr(:block)
 @test_throws ParseError Meta.parse("(,)")
 @test_throws ParseError Meta.parse("(;,)")
@@ -1322,7 +1322,7 @@ end
 @test Meta.parse("-(x)^2")     == Expr(:call, :-, Expr(:call, :^, :x, 2))
 @test Meta.parse("-(a=1)^2")   == Expr(:call, :-, Expr(:call, :^, Expr(:(=), :a, 1), 2))
 @test Meta.parse("-(x;y)^2")   == Expr(:call, :-, Expr(:call, :^, Expr(:block, :x, LineNumberNode(1,:none), :y), 2))
-@test_skip Meta.parse("-(;)^2")     == Expr(:call, :-, Expr(:call, :^, Expr(:tuple, Expr(:parameters)), 2))
+@test Meta.parse("-(;)^2")     == Expr(:call, :-, Expr(:call, :^, Expr(:tuple, Expr(:parameters)), 2))
 @test Meta.parse("-(;;;;)^2")  == Expr(:call, :-, Expr(:call, :^, Expr(:block), 2))
 @test Meta.parse("-(x;;;)^2")  == Expr(:call, :-, Expr(:call, :^, Expr(:block, :x), 2))
 @test Meta.parse("+((1,2))")   == Expr(:call, :+, Expr(:tuple, 1, 2))