@warn_unqualified_access attribute name

[hooman (Hooman Mehr)]

Here is one possible use case:

In SwiftUI.View body, accidentally put `padding()` (all by itself, no dot in front): it compiles fine, but preview doesn't work/run show blank screen or crash

Here is a short sample code to show what is happening. Note that the only difference between bar() and baz() is the dot before foo(). The solution for catching such errors is using @warn_unqualified_access attribute as indicated in the comments: protocol P { func foo() } struct S1: P { func foo() { print("S1 foo()") } } struct S2: P { var s1 = S1() // Uncomment the following to get a warning: //@warn_unqualified_access func foo() { print("S2 foo()") } func b…