feat: better errors for mixed tuples in ref

Author: MilesCranmer

src/macros.jl

@@ -289,6 +289,8 @@ function _ref(lifetime_expr::Expr, expr::Expr, mut::Bool)
                     $(refs...)
                 end,
             )
+        elseif Meta.isexpr(dest, :tuple) ⊻ Meta.isexpr(src, :tuple)
+            error("Cannot mix tuple and non-tuple arguments in @ref")
         else
             return esc(:($dest = $(ref)($lifetime, $src, $(QuoteNode(dest)), Val($mut))))
         end

test/reference_tests.jl

@@ -208,6 +208,18 @@ end
         @test rx2 == [1]
     end
 
+    # Need to pass tuple on both sides
+    @test_throws(
+        "Cannot mix tuple and non-tuple arguments in @ref", @eval @ref ~lt (a, b, c) = d
+    )
+    @test_throws(
+        "Cannot mix tuple and non-tuple arguments in @ref", @eval @ref ~lt a = (b, c, d)
+    )
+    @test_throws(
+        "Number of variables must match number of values in tuple unpacking",
+        @eval @ref ~lt (a, b) = (c, d, e, f)
+    )
+
     # Test mutable references
     @own :mut mx = [1]
     @own :mut my = [2]