v9 Async method not decompiled

I'm getting the async state machine initialisation when viewing an async method instead of the code. This is a method sitting inside a class that inherits from Microsoft.AspNet.Identity.UserManager<ApplicationUser>

VS2015 update 1
Targeting .NET 4.6

I have ASP.NET 5 RC1 installed, but project is an ASP.NET 4 project ( i.e. .csproj )

Original

        public async Task<IdentityResult> AddClaimsAsync(string userId, IEnumerable<Claim> claims, IEqualityComparer<Claim> existingMatcher = null)
        {
            IUserClaimStore<ApplicationUser, string> claimStore = this.Store as IUserClaimStore<ApplicationUser, string>;

            ApplicationUser user = await this.FindByIdAsync(userId).WithCurrentCulture();

            if (user == null)
            {
                throw new InvalidOperationException("UserId not found.");
            }

            var matcher = existingMatcher ?? Framework.Claims.ClaimComparers.ClaimTypeIssuerAndValue;

            var existingClaims = await claimStore.GetClaimsAsync(user).WithCurrentCulture();

            var existingToRemove = claims.SelectMany(claim => existingClaims.Where(existing => matcher.Equals(claim, existing))).ToList();

            foreach(Claim claim in existingToRemove)
            {
                await claimStore.RemoveClaimAsync(user, claim).WithCurrentCulture();
            }
            foreach (Claim claim in claims)
            {
                await claimStore.AddClaimAsync(user, claim).WithCurrentCulture();
            }

            return await this.UpdateAsync(user).WithCurrentCulture();
        }

Decompiled

[AsyncStateMachine(typeof(<AddClaimsAsync>d__2)), DebuggerStepThrough]
public Task<IdentityResult> AddClaimsAsync(ApplicationUser user, IEnumerable<Claim> claims, IEqualityComparer<Claim> existingMatcher = null)
{
    <AddClaimsAsync>d__2 stateMachine = new <AddClaimsAsync>d__2 {
        <>4__this = this,
        user = user,
        claims = claims,
        existingMatcher = existingMatcher,
        <>t__builder = AsyncTaskMethodBuilder<IdentityResult>.Create(),
        <>1__state = -1
    };
    stateMachine.<>t__builder.Start<<AddClaimsAsync>d__2>(ref stateMachine);
    return stateMachine.<>t__builder.Task;
}