From d3ae522061292aa646ef916b8bcf4ec33d1b012c Mon Sep 17 00:00:00 2001
From: Ary Borenszweig <aborenszweig@manas.com.ar>
Date: Fri, 7 Apr 2017 15:57:40 -0300
Subject: [PATCH] Fixed #4249: parse error with macros with %{}

---
 spec/compiler/parser/parser_spec.cr  | 2 ++
 src/compiler/crystal/syntax/lexer.cr | 7 ++++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/spec/compiler/parser/parser_spec.cr b/spec/compiler/parser/parser_spec.cr
index 12fd3aa5109b..9dc222e56a25 100644
--- a/spec/compiler/parser/parser_spec.cr
+++ b/spec/compiler/parser/parser_spec.cr
@@ -756,6 +756,8 @@ describe "Parser" do
 
   it_parses "macro foo;bar{% begin %}body{% end %}baz;end", Macro.new("foo", [] of Arg, Expressions.from(["bar".macro_literal, MacroIf.new(true.bool, "body".macro_literal), "baz;".macro_literal] of ASTNode))
 
+  it_parses "macro x\n%{}\nend", Macro.new("x", body: MacroLiteral.new("%{}\n"))
+
   it_parses "def foo : Int32\n1\nend", Def.new("foo", body: 1.int32, return_type: "Int32".path)
   it_parses "def foo(x) : Int32\n1\nend", Def.new("foo", args: ["x".arg], body: 1.int32, return_type: "Int32".path)
 
diff --git a/src/compiler/crystal/syntax/lexer.cr b/src/compiler/crystal/syntax/lexer.cr
index 58654c75020f..3274e72572db 100644
--- a/src/compiler/crystal/syntax/lexer.cr
+++ b/src/compiler/crystal/syntax/lexer.cr
@@ -2118,7 +2118,12 @@ module Crystal
             break
           end
         when '}'
-          if @macro_curly_count > 0
+          if delimiter_state && delimiter_state.end == '}'
+            delimiter_state = delimiter_state.with_open_count_delta(-1)
+            if delimiter_state.open_count == 0
+              delimiter_state = nil
+            end
+          elsif @macro_curly_count > 0
             # Once we find the final '}' that closes the interpolation,
             # we are back inside the delimiter
             if @macro_curly_count == 1