[Patch] BUG 19551 explicit instantiation confusion for a function with a deduced return type already been instantiated

Hi,

Attaching Patch for bug 19551. Please help in reviewing it.

I am checking for return type as auto in template declaration and explicit template instantiation. This patch resolves bug 19551 and has no regressions. I am not sure though if this is the correct approach.

Please help in reviewing and corrections.

PR_19551.patch (2.72 KB)