From 66f336d37e123482c9fe5201750564537c420cbe Mon Sep 17 00:00:00 2001
From: Jake Bolewski <jakebolewski@gmail.com>
Date: Tue, 11 Aug 2015 11:49:16 -0400
Subject: [PATCH] restrict Vararg{} to trailing position in Tuple type
 constructor

---
 src/builtins.c | 12 ++++++++++--
 test/core.jl   |  4 ++++
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/src/builtins.c b/src/builtins.c
index a105e46ba0471..0bc6bdabcdd17 100644
--- a/src/builtins.c
+++ b/src/builtins.c
@@ -1000,8 +1000,7 @@ JL_CALLABLE(jl_f_instantiate_type)
 {
     JL_NARGSV(instantiate_type, 1);
     if (args[0] == (jl_value_t*)jl_uniontype_type) {
-        size_t i;
-        for(i=1; i < nargs; i++) {
+        for(size_t i=1; i < nargs; i++) {
             jl_value_t* ty = args[i];
             if ((!jl_is_type(ty) && !jl_is_typevar(ty)) || jl_is_vararg_type(ty)) {
                 jl_type_error_rt("apply_type", "parameter of Union",
@@ -1009,6 +1008,15 @@ JL_CALLABLE(jl_f_instantiate_type)
             }
         }
     }
+    else if (args[0] == (jl_value_t*)jl_tuple_type) {
+        for(size_t i=1; i < nargs; i++) {
+            jl_value_t* ty = args[i];
+            if (jl_is_vararg_type(ty) && i != nargs-1) {
+                jl_type_error_rt("apply_type", "parameter of Tuple",
+                                 (jl_value_t*)jl_type_type, args[i]);
+            }
+        }
+    }
     else if (!jl_is_datatype(args[0])) {
         JL_TYPECHK(instantiate_type, typector, args[0]);
     }
diff --git a/test/core.jl b/test/core.jl
index b2719de645b53..aa9938207fc72 100644
--- a/test/core.jl
+++ b/test/core.jl
@@ -3203,3 +3203,7 @@ end
 
 # don't allow Vararg{} in Union{} type constructor
 @test_throws TypeError Union{Int,Vararg{Int}}
+
+# don't allow Vararg{} in Tuple{} type constructor in non-trailing position
+@test_throws TypeError Tuple{Vararg{Int32},Int64,Float64}
+@test_throws TypeError Tuple{Int64,Vararg{Int32},Float64}