2 files changed, 4 insertions, 6 deletions
diff --git a/src/libexpr/lexer.l b/src/libexpr/lexer.l
index b61d5ea7713c..fe2ff75d0d1c 100644
--- a/src/libexpr/lexer.l
+++ b/src/libexpr/lexer.l
@@ -9,7 +9,6 @@
 
 %{
 #include "nixexpr.hh"
-#define BISON_HEADER_HACK
 #include "parser-tab.hh"
 
 using namespace nix;
diff --git a/src/libexpr/parser.y b/src/libexpr/parser.y
index 66edfb548b32..f78780b1d486 100644
--- a/src/libexpr/parser.y
+++ b/src/libexpr/parser.y
@@ -4,10 +4,10 @@
 %error-verbose
 %defines
 /* %no-lines */
-%parse-param { yyscan_t scanner }
-%parse-param { ParseData * data }
-%lex-param { yyscan_t scanner }
-%lex-param { ParseData * data }
+%parse-param { void * scanner }
+%parse-param { nix::ParseData * data }
+%lex-param { void * scanner }
+%lex-param { nix::ParseData * data }
 %expect 1
 %expect-rr 1
 
@@ -52,7 +52,6 @@ namespace nix {
 
 #include "parser-tab.hh"
 #include "lexer-tab.hh"
-#define YYSTYPE YYSTYPE // workaround a bug in Bison 2.4
 
 #include <stdio.h>
 #include <stdlib.h>