resolve warning in typinf.c
Merge pull request #3999 from WalterBright/typinf-warning

resolve warning in typinf.c
fix Issue 13484 - Template type deduction from delegate parameter fails

The implicit conversion of expressions to delegates was added in 0.165 (a2b1fa4978948ca4d293c38666bd607c03ba791a, http://www.digitalmars.com/d/1.0/changelog2.html#new0165), but it was replaced with lazy parameter.