Fix lexing MacroVar syntax in literal

Author: straight-shoota

spec/compiler/parser/parser_spec.cr

@@ -146,9 +146,9 @@ module Crystal
     it_parses %(macro foo\n%q(%t{)\nend), Macro.new("foo", body: Expressions.from(["%q(%t".macro_literal, "{)\n".macro_literal] of ASTNode))
     it_parses %(macro foo\n%(%t{)\nend), Macro.new("foo", body: Expressions.from(["%(%t".macro_literal, "{)\n".macro_literal] of ASTNode))
 
-    assert_syntax_error %({% begin %}\n%q(%t{})\n{% end %}), %(unexpected token: "}") # #16772
+    it_parses %({% begin %}\n%q(%t{})\n{% end %}), MacroIf.new(true.bool, Expressions.from(["\n".macro_literal, "%q(%t".macro_literal, "{})\n".macro_literal] of ASTNode))
     it_parses %({% begin %}\n%(%t{})\n{% end %}), MacroIf.new(true.bool, Expressions.from(["\n%(%t".macro_literal, "{})\n".macro_literal] of ASTNode))
-    assert_syntax_error %({% begin %}\n%q(%t{)\n{% end %}), %{unexpected token: ")"}
+    it_parses %({% begin %}\n%q(%t{)\n{% end %}), MacroIf.new(true.bool, Expressions.from(["\n".macro_literal, "%q(%t".macro_literal, "{)\n".macro_literal] of ASTNode))
     it_parses %({% begin %}\n%(%t{)\n{% end %}), MacroIf.new(true.bool, Expressions.from(["\n%(%t".macro_literal, "{)\n".macro_literal] of ASTNode))
 
     it_parses ":foo", "foo".symbol

src/compiler/crystal/syntax/lexer.cr

@@ -1898,19 +1898,19 @@ module Crystal
           end
           whitespace = false
         when '%'
-          case char = peek_next_char
-          when '(', '[', '<', '{', '|'
-            next_char
-            delimiter_state = Token::DelimiterState.new(:string, char, closing_char)
-          else
-            whitespace = false
-            # Don't break if this looks like a prefixed percent literal that will
-            # be handled before the main loop (e.g., %Q|...|, %w|...|, etc.)
-            if !delimiter_state && ident_start?(char)
-              is_percent_literal =
-                char.in?('q', 'Q', 'w', 'i', 'r', 'x') &&
-                  lookahead { next_char; peek_next_char.in?('(', '<', '[', '{', '|') }
-              break unless is_percent_literal
+          if !delimiter_state
+            case char = peek_next_char
+            when '(', '[', '<', '{', '|'
+              next_char
+              delimiter_state = Token::DelimiterState.new(:string, char, closing_char)
+            else
+              whitespace = false
+              # Don't break if this looks like a prefixed percent literal that will
+              # be handled before the main loop (e.g., %Q|...|, %w|...|, etc.)
+              if !delimiter_state && ident_start?(char)
+                # This looks like a macro var or a percent literal. Both are handled further above.
+                break
+              end
             end
           end
         when '#'