From 49d998122f68b54d554323129427a6b9d7a9ceec Mon Sep 17 00:00:00 2001
From: Caspian Baska <email@caspian.computer>
Date: Mon, 17 Oct 2022 23:35:25 +0800
Subject: [PATCH 1/2] Fix for unexpected literals in class definitions

---
 spec/compiler/parser/parser_spec.cr   | 11 +++++++++++
 src/compiler/crystal/syntax/parser.cr |  6 ++++++
 2 files changed, 17 insertions(+)

diff --git a/spec/compiler/parser/parser_spec.cr b/spec/compiler/parser/parser_spec.cr
index b5e0a0301fc6..581b1e9dbe15 100644
--- a/spec/compiler/parser/parser_spec.cr
+++ b/spec/compiler/parser/parser_spec.cr
@@ -253,6 +253,17 @@ module Crystal
       assert_syntax_error "foo { |(#{kw})| }", "cannot use '#{kw}' as a block parameter name", 1, 9
     end
 
+    describe "literals in class definitions" do
+      # #11209
+      %w("a" 'a' [1] {1} {|a|a} ->{} ->(x : Bar){} :Bar :bar %x() %w() %()).each do |invalid|
+        assert_syntax_error "class Foo#{invalid}; end"
+        assert_syntax_error "class Foo#{invalid} < Baz; end"
+        assert_syntax_error "class Foo#{invalid} < self; end"
+        assert_syntax_error "class Foo < Baz#{invalid}; end"
+        assert_syntax_error "class Foo < self#{invalid}; end"
+      end
+    end
+
     it_parses "def self.foo\n1\nend", Def.new("foo", body: 1.int32, receiver: "self".var)
     it_parses "def self.foo()\n1\nend", Def.new("foo", body: 1.int32, receiver: "self".var)
     it_parses "def self.foo=\n1\nend", Def.new("foo=", body: 1.int32, receiver: "self".var)
diff --git a/src/compiler/crystal/syntax/parser.cr b/src/compiler/crystal/syntax/parser.cr
index ce3a1cc9b38d..4f7af8e54f2c 100644
--- a/src/compiler/crystal/syntax/parser.cr
+++ b/src/compiler/crystal/syntax/parser.cr
@@ -1637,6 +1637,10 @@ module Crystal
       name = parse_path
       skip_space
 
+      unexpected_token unless @token.type.op_lt? ||     # Inheritance
+                              @token.type.op_lparen? || # Generic Arguments
+                              @token.type.newline? || @token.type.op_semicolon?
+
       type_vars, splat_index = parse_type_vars
 
       superclass = nil
@@ -1649,6 +1653,8 @@ module Crystal
         else
           superclass = parse_generic
         end
+
+        unexpected_token unless @token.type.newline? || @token.type.op_semicolon? || @token.type.space?
       end
       skip_statement_end
 

From 857f3a0de985e38a40826cbfca735ba5fbe68352 Mon Sep 17 00:00:00 2001
From: Caspian Baska <email@caspian.computer>
Date: Tue, 18 Oct 2022 01:32:11 +0800
Subject: [PATCH 2/2] Account for single-line class declarations

---
 src/compiler/crystal/syntax/parser.cr | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/compiler/crystal/syntax/parser.cr b/src/compiler/crystal/syntax/parser.cr
index 4f7af8e54f2c..4c41220d4234 100644
--- a/src/compiler/crystal/syntax/parser.cr
+++ b/src/compiler/crystal/syntax/parser.cr
@@ -1639,7 +1639,7 @@ module Crystal
 
       unexpected_token unless @token.type.op_lt? ||     # Inheritance
                               @token.type.op_lparen? || # Generic Arguments
-                              @token.type.newline? || @token.type.op_semicolon?
+                              is_statement_end?
 
       type_vars, splat_index = parse_type_vars
 
@@ -1654,7 +1654,7 @@ module Crystal
           superclass = parse_generic
         end
 
-        unexpected_token unless @token.type.newline? || @token.type.op_semicolon? || @token.type.space?
+        unexpected_token unless @token.type.space? || is_statement_end?
       end
       skip_statement_end
 
@@ -1674,6 +1674,10 @@ module Crystal
       class_def
     end
 
+    def is_statement_end?
+      @token.type.newline? || @token.type.op_semicolon? || @token.keyword?(:end)
+    end
+
     def parse_type_vars
       type_vars = nil
       splat_index = nil