The flow was such that we recorded subtype constraints regardless of the
subject type's nature. Extract value generics handling out of the
devious `else if` chain, and never record any subtype constraints if the
subject type is a non-type parameter.
While we're here, generalize the diagnostic message for user-written
subtype constraints on value generic parameters and emit it
consistently, not just if the right-hand side contains a protocol type.
This commit introduces a performance hint check that warns on the use of
existential any in variable declarations, function and closure parameters and
returns, and typealiases.
Dependent members cannot be simplified if base type contains unresolved
pack expansion type variables because they don't give enough information
to substitution logic to form a correct type. For example:
```
protocol P { associatedtype V }
struct S<each T> : P { typealias V = (repeat (each T)?) }
```
If pack expansion is represented as `$T1` and its pattern is `$T2`, a
reference to `V` would get a type `S<Pack{$T}>.V` and simplified version
would be `Optional<Pack{$T1}>` instead of `Pack{repeat Optional<$T2>}`
because `$T1` is treated as a substitution for `each T` until bound.
Resolves: rdar://161207705
We already have -suppress-warnings and -suppress-remarks; this patch
adds support for suppressing notes too. Doing so is useful for -verify
tests where we don't really care about the emitted notes.
`span` is not available in all versions of libstd++, so make it a
conditional header. Also adds other missing c++20 headers.
Fixing this triggered an assert when importing a constant initialized
`wchar_t` variable, so that is also fixed. The reason is that `wchar_t`
is mapped to `Unicode.Scalar`, which cannot be directly initialized by
integer literals in Swift, triggering an assert when looking up the
protocol conformance for `_ExpressibleByBuiltinIntegerLiteral`.
rdar://162074714
Lifetime diagnostics may report an error within an implicit initializer or
accessor. The source location is misleading in these cases and causes much
consternation.
Filter out any duplicate notes to help cut down on the noise for
request cycle diagnostics. Some of the note locations here still aren't
great, but this at least stops us from repeating them for each
intermediate request.
Make sure we canonicalize the original type for an ErrorType to ensure
that diagnostic logic can coalesce ErrorTypes that have the same
canonical type.
If we failed to construct a rewrite system for a protocol, either because
the Knuth-Bendix algorithm failed or because of a request cycle while
resolving requirements, we would end up in a situation where the resulting
rewrite system didn't include all conformance requirements and associated
types, so name lookup would find declarations whose interface types are
not valid type parameters.
Fix this by propagating failure better and just doing nothing in
getReducedTypeParameter().
Fixes rdar://147277543.
@c @implementation relies on matching the original C declaration. The
lookup for the original C declaration was doing the wrong kind of
lookup, meaning that it could only find the C declaration if it came
through a bridging header, and not through a normal module import.
Using unqualified lookup here finds the name appropriately.
Clarify the diagnostics here as well to not talk about umbrella and
bridging headers.
Fixes rdar://161909754.
The `_Concurrency` and `_StringProcessing` modules are implementation details of the standard library; to developers, their contents should behave as though they are declared directly within module `Swift`. This is the exact same behavior we expect of cross-import overlays, so treat these modules as though they are cross-import overlays with no bystanding module.
Because these modules don’t re-export the standard library, it’s also necessary to treat `Swift` as a separately imported overlay of itself; do so and make that actually work.
This check will run on each type-checked primary input of the current compilation and emit a warning diagnostic for all discovered occurences of this code pattern when the performance hint diagnostic is enabled
