https://issues.dlang.org/show_bug.cgi?id=19698

          Issue ID: 19698
           Summary: ReplaceType barfs on enums with base type of string
           Product: D
           Version: D2
          Hardware: x86
                OS: Mac OS X
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: phobos
          Assignee: nobody@puremagic.com
          Reporter: ali.akhtarzada@gmail.com

cat > bug.d << CODE
import std.typecons: ReplaceType;

enum E : string { one = "one" }
pragma(msg, ReplaceType!(int, int, E));
static assert(is(ReplaceType!(int, int, E) == E));
CODE

dmd -c bug

Prints:

bug.d(5): Error: static assert:  is(string == E) is false

Related to issue 15168

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