From 808cdd6f3429e4140df1e8a84a894de2b9fb0ba0 Mon Sep 17 00:00:00 2001
From: Geod24 <pro.mathias.lang@gmail.com>
Date: Mon, 29 Jul 2019 13:57:37 +0900
Subject: [PATCH] std.range.enumerate should work with a non-mutable start
 index

The deduced type for `Enumerator` could contain type modifier
(`const`, `immutable`), but the type was used directly as
a state variable.
---
 std/range/package.d | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/std/range/package.d b/std/range/package.d
index 00771b7fe0a..b707c3c02ab 100644
--- a/std/range/package.d
+++ b/std/range/package.d
@@ -10163,7 +10163,7 @@ do
         private:
         alias ElemType = Tuple!(Enumerator, "index", ElementType!Range, "value");
         Range range;
-        Enumerator index;
+        Unqual!Enumerator index;
 
         public:
         ElemType front() @property
@@ -10272,6 +10272,14 @@ pure @safe nothrow unittest
     assert(aa[1]);
 }
 
+// Make sure passing qualified types works
+pure @safe nothrow unittest
+{
+    char[4] v;
+    immutable start = 2;
+    v[2 .. $].enumerate(start);
+}
+
 pure @safe nothrow unittest
 {
     import std.internal.test.dummyrange : AllDummyRanges;