Protect nilable procs with parenthesis when translating to RBS

Signed-off-by: Alexandre Terrasa <alexandre.terrasa@shopify.com>
Shopify · Jan 14, 2025 · b043e8f · b043e8f
1 parent e9c6406
commit b043e8f
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diff --git a/lib/rbi/rbs_printer.rb b/lib/rbi/rbs_printer.rb
@@ -885,7 +885,13 @@ def visit_attached_class(type)
 
     sig { params(type: Type::Nilable).void }
     def visit_nilable(type)
+      if type.type.is_a?(Type::Proc)
+        @string << "("
+      end
       visit(type.type)
+      if type.type.is_a?(Type::Proc)
+        @string << ")"
+      end
       @string << "?"
     end
 

diff --git a/test/rbi/rbs_printer_test.rb b/test/rbi/rbs_printer_test.rb
@@ -530,6 +530,17 @@ def foo: -> instance
       RBI
     end
 
+    def test_print_nilable_proc
+      rbi = parse_rbi(<<~RBI)
+        sig { params(x: T.nilable(T.proc.void)) }
+        def foo(x); end
+      RBI
+
+      assert_equal(<<~RBI, rbi.rbs_string)
+        def foo: ((^-> void)? x) -> void
+      RBI
+    end
+
     def test_print_t_structs
       rbi = parse_rbi(<<~RBI)
         class Foo < T::Struct; end