along with recent policy changes:
- For expression types that are not specifically handled, make sure to
produce a general "unused value" warning, catching a bunch of unused
values in the testsuite.
- For unused operator results, diagnose them as uses of the operator
instead of "calls".
- For calls, mutter the type of the result for greater specificity.
- For initializers, mutter the type of the initialized value.
- Look through OpenExistentialExpr's so we can handle protocol member
references propertly.
- Look through several other expressions so we handle @discardableResult
better.
In failable initializers the "return from initializer without initializing all stored properties" (resp. "return from enum initializer method without storing to 'self'" for enums) diagnostic is now reported at the early return instead of the end of the initializer.
its fields are initialized. Before:
t.swift:18:24: error: variable 'self.B' captured by a closure before being initialized
after:
t.swift:19:24: error: 'self' captured by a closure before all members were initialized
self.A.withCString { cString -> () in
^
t.swift:14:7: note: 'self.B' not initialized
var B: Int
^
This drives home the fact that 'self' is being captured here, not the individual
properties.
Partial applications of a root self value are an escape point, not a load. This
improves the diagnostic in this case from:
t.swift:18:24: error: variable 'self.B' used before being initialized
self.A.withCString { cString -> () in
^
to:
t.swift:18:24: error: variable 'self.B' captured by a closure before being initialized
self.A.withCString { cString -> () in
^
When a root class delegates to a non-class-bound protocol method, the self value
gets wrapped up in a SIL alloc_stack so it can be passed by address. Recognize
that the store involved is doing this, so we can provide a more specific diagnostic.
Before this, we produced:
variable 'self.x' used before being initialized
Now we produce:
error: use of 'self' in method call 'getg' before all stored properties are initialized
note: 'self.x' not initialized
