[ruby/prism] [Bug #17398] Allow `private def hello = puts "Hello"`

This was a limitation of parse.y that prism intentionally replicated.

https://github.com/ruby/prism/commit/8fd12d594c

11 files changed, 49 insertions, 15 deletions

diff --git a/prism/prism.c b/prism/prism.c
index daf69d2ef9..337b77637b 100644
--- a/prism/prism.c
+++ b/prism/prism.c
@@ -19585,13 +19585,13 @@ parse_expression_prefix(pm_parser_t *parser, pm_binding_power_t binding_power, b
                 pm_do_loop_stack_push(parser, false);
                 statements = (pm_node_t *) pm_statements_node_create(parser);
 
-                // In endless method bodies, we need to handle command calls carefully.
-                // We want to allow command calls in assignment context but maintain
-                // the same binding power to avoid changing how operators are parsed.
-                // Note that we're intentionally NOT allowing code like `private def foo = puts "Hello"`
-                // because the original parser, parse.y, can't handle it and we want to maintain the same behavior
-                bool allow_command_call = (binding_power == PM_BINDING_POWER_ASSIGNMENT) ||
-                                         (binding_power < PM_BINDING_POWER_COMPOSITION);
+                bool allow_command_call;
+                if (parser->version >= PM_OPTIONS_VERSION_CRUBY_3_5) {
+                    allow_command_call = accepts_command_call;
+                } else {
+                    // Allow `def foo = puts "Hello"` but not `private def foo = puts "Hello"`
+                    allow_command_call = binding_power == PM_BINDING_POWER_ASSIGNMENT || binding_power < PM_BINDING_POWER_COMPOSITION;
+                }
 
                 pm_node_t *statement = parse_expression(parser, PM_BINDING_POWER_DEFINED + 1, allow_command_call, false, PM_ERR_DEF_ENDLESS, (uint16_t) (depth + 1));
 
diff --git a/test/prism/errors/endless_method_command_call.txt b/test/prism/errors/endless_method_command_call.txt
new file mode 100644
index 0000000000..e6a328c294
--- /dev/null
+++ b/test/prism/errors/endless_method_command_call.txt
@@ -0,0 +1,3 @@
+private :m, def hello = puts "Hello"
+                             ^ unexpected string literal, expecting end-of-input
+
diff --git a/test/prism/errors/private_endless_method.txt b/test/prism/errors/private_endless_method.txt
deleted file mode 100644
index 8aae5e0cd3..0000000000
--- a/test/prism/errors/private_endless_method.txt
+++ /dev/null
@@ -1,3 +0,0 @@
-private def foo = puts "Hello"
-                       ^ unexpected string literal, expecting end-of-input
-
diff --git a/test/prism/errors_test.rb b/test/prism/errors_test.rb
index 62bbd8458b..9dd4aea728 100644
--- a/test/prism/errors_test.rb
+++ b/test/prism/errors_test.rb
@@ -100,6 +100,15 @@ module Prism
       end
     end
 
+    def test_private_endless_method
+      source = <<~RUBY
+        private def foo = puts "Hello"
+      RUBY
+
+      assert_predicate Prism.parse(source, version: "3.4"), :failure?
+      assert_predicate Prism.parse(source), :success?
+    end
+
     private
 
     def assert_errors(filepath)
diff --git a/test/prism/fixtures/endless_methods_command_call.txt b/test/prism/fixtures/endless_methods_command_call.txt
new file mode 100644
index 0000000000..91a9d156d5
--- /dev/null
+++ b/test/prism/fixtures/endless_methods_command_call.txt
@@ -0,0 +1,8 @@
+private def foo = puts "Hello"
+private def foo = puts "Hello", "World"
+private def foo = puts "Hello" do expr end
+private def foo() = puts "Hello"
+private def foo(x) = puts x
+private def obj.foo = puts "Hello"
+private def obj.foo() = puts "Hello"
+private def obj.foo(x) = puts x
diff --git a/test/prism/fixtures_test.rb b/test/prism/fixtures_test.rb
index 124a834317..b4b656fcf4 100644
--- a/test/prism/fixtures_test.rb
+++ b/test/prism/fixtures_test.rb
@@ -8,7 +8,6 @@ module Prism
   class FixturesTest < TestCase
     except = []
 
-
     if RUBY_VERSION < "3.3.0"
       # Ruby < 3.3.0 cannot parse heredocs where there are leading whitespace
       # characters in the heredoc start.
@@ -25,7 +24,9 @@ module Prism
       except << "whitequark/ruby_bug_19281.txt"
     end
 
-    except << "leading_logical.txt" if RUBY_VERSION < "3.5.0"
+    # Leaving these out until they are supported by parse.y.
+    except << "leading_logical.txt"
+    except << "endless_methods_command_call.txt"
 
     Fixture.each(except: except) do |fixture|
       define_method(fixture.test_name) { assert_valid_syntax(fixture.read) }
diff --git a/test/prism/lex_test.rb b/test/prism/lex_test.rb
index abce18a0ad..4eacbab3e1 100644
--- a/test/prism/lex_test.rb
+++ b/test/prism/lex_test.rb
@@ -45,6 +45,9 @@ module Prism
     # https://bugs.ruby-lang.org/issues/20925
     except << "leading_logical.txt"
 
+    # https://bugs.ruby-lang.org/issues/17398#note-12
+    except << "endless_methods_command_call.txt"
+
     Fixture.each(except: except) do |fixture|
       define_method(fixture.test_name) { assert_lex(fixture) }
     end
diff --git a/test/prism/locals_test.rb b/test/prism/locals_test.rb
index e0e9a45855..950e7118af 100644
--- a/test/prism/locals_test.rb
+++ b/test/prism/locals_test.rb
@@ -29,7 +29,11 @@ module Prism
     except = [
       # Skip this fixture because it has a different number of locals because
       # CRuby is eliminating dead code.
-      "whitequark/ruby_bug_10653.txt"
+      "whitequark/ruby_bug_10653.txt",
+
+      # Leaving these out until they are supported by parse.y.
+      "leading_logical.txt",
+      "endless_methods_command_call.txt"
     ]
 
     Fixture.each(except: except) do |fixture|
diff --git a/test/prism/ruby/parser_test.rb b/test/prism/ruby/parser_test.rb
index 129c38a3b5..98740f0973 100644
--- a/test/prism/ruby/parser_test.rb
+++ b/test/prism/ruby/parser_test.rb
@@ -67,6 +67,9 @@ module Prism
 
       # Cannot yet handling leading logical operators.
       "leading_logical.txt",
+
+      # Ruby >= 3.5 specific syntax
+      "endless_methods_command_call.txt",
     ]
 
     # These files contain code that is being parsed incorrectly by the parser
diff --git a/test/prism/ruby/ripper_test.rb b/test/prism/ruby/ripper_test.rb
index 6372024878..39325137ba 100644
--- a/test/prism/ruby/ripper_test.rb
+++ b/test/prism/ruby/ripper_test.rb
@@ -29,7 +29,10 @@ module Prism
       "whitequark/lvar_injecting_match.txt",
 
       # Ripper fails to understand some structures that span across heredocs.
-      "spanning_heredoc.txt"
+      "spanning_heredoc.txt",
+
+      # https://bugs.ruby-lang.org/issues/17398#note-12
+      "endless_methods_command_call.txt",
     ]
 
     # Skip these tests that we haven't implemented yet.
diff --git a/test/prism/ruby/ruby_parser_test.rb b/test/prism/ruby/ruby_parser_test.rb
index f4f0f331fb..bcaed79791 100644
--- a/test/prism/ruby/ruby_parser_test.rb
+++ b/test/prism/ruby/ruby_parser_test.rb
@@ -74,7 +74,10 @@ module Prism
       "whitequark/ruby_bug_11989.txt",
       "whitequark/ruby_bug_18878.txt",
       "whitequark/ruby_bug_19281.txt",
-      "whitequark/slash_newline_in_heredocs.txt"
+      "whitequark/slash_newline_in_heredocs.txt",
+
+      # Ruby >= 3.5 specific syntax
+      "endless_methods_command_call.txt",
     ]
 
     Fixture.each(except: failures) do |fixture|