Does not wrap raw pointer if set invalid argument in function call

Development Compiler
#1 
swift --version                                                           11:40:11
Apple Swift version 4.2-dev (LLVM b7ee930770, Clang 5bae8c2e73, Swift 4160301759)

Function signature for test:

public func pcre2_compile_16(
    _: PCRE2_SPTR16!,
    _: Int, 
    _: UInt32,
    _: UnsafeMutablePointer<Int32>!,
    _: UnsafeMutablePointer<Int>!,
    _: OpaquePointer!
) -> OpaquePointer!

Valid call:

let re = context.pattern.withCString(encodedAs: UTF16.self) {
            return pcre2_compile_16(
                    $0,
                    context.pattern.utf16.count,
                    0,
                    &errorCode,
                    &errorOffset,
                    nil
            )
        }

Call with invalid argument:

let re = context.pattern.withCString(encodedAs: UTF16.self) {
            return pcre2_compile_16(
                    $0,
                    context.pattern.utf16.count,
                    "hello", /// <--- must be UInt32, not String 
                    &errorCode,
                    &errorOffset,
                    nil
            )
        }

Actual results:

cannot convert value of type 'UnsafePointer<_>' to expected argument type 'PCRE2_SPTR16?' (aka 'Optional<UnsafePointer>')