Runtime crash: T constraint ignored for any Alias<T> when typealias Alias<T> = ProtoA & ProtoB<T>

[bubski]

Description

No response

Reproduction

protocol ProtoA {}

protocol ProtoB<C> {
    associatedtype C
    var val: C { get }
}

typealias Alias<T> = ProtoA & ProtoB<T>

struct Foo: ProtoA, ProtoB {
    var val: String { "hello" }
}

// This should not compile.
// `Foo` matches `Alias<String>` but not `Alias<[String]>`.
var foo: any Alias<[String]> {
    Foo()
}

print(foo.val) // crash

https://godbolt.org/z/754fnc3qY

Stack dump

Thread 0 Crashed::  Dispatch queue: com.apple.main-thread
0   libswiftCore.dylib            	       0x1acf1a6c8 swift_retain + 44
1   libswiftCore.dylib            	       0x1acf1f714 swift::metadataimpl::BufferValueWitnesses<swift::metadataimpl::ValueWitnesses<swift::metadataimpl::BridgeObjectBox>, true, 8ul, 8ul, (swift::metadataimpl::FixedPacking)1>::initializeBufferWithCopyOfBuffer(swift::TargetValueBuffer<swift::InProcess>*, swift::TargetValueBuffer<swift::InProcess>*, swift::TargetMetadata<swift::InProcess> const*) + 28
2   libswiftCore.dylib            	       0x1aceb88f8 outlined init with copy of Any + 76
3   libswiftCore.dylib            	       0x1acd11d5c specialized _print<A>(_:separator:terminator:to:) + 232
4   libswiftCore.dylib            	       0x1acd10efc print(_:separator:terminator:) + 192
5   main                          	       0x10442bb20 main + 312
6   dyld                          	       0x19cb2e0e0 0x19cb28000 + 24800

Expected behavior

The code should not compile.
There should be an error emitted for type mismatch in:

// This should not compile.
// `Foo` matches `Alias<String>` but not `Alias<[String]>`.
var foo: any Alias<[String]> {
    Foo()
}

Environment

swift-driver version: 1.87.3 Apple Swift version 5.9.2 (swiftlang-5.9.2.2.56 clang-1500.1.0.2.5)
Target: arm64-apple-macosx14.0

Additional information

For what its worth, this only happens when typealias is involved.
Otherwise, there's an unrelated compilation error:

main.swift:14:23: error: non-protocol, non-class type 'ProtoB<[String]>' cannot be used within a protocol-constrained type
var foo: any ProtoA & ProtoB<[String]> {
                      ^

#63877 (comment) leads me to believe that this particular error should not actually exist,
and both Alias<[String]> and ProtoA & ProtoB<[String]> should be allowed and handled properly.

[zvonicek]

update: still crashes on Swift 5.10, now with the following message

Failed to reconstruct type for $s6output6ProtoA_AA0B1BpSaySSG1CAaCPRts_XPD
Original type:
(existential_type
  (protocol_composition_type
    (protocol_type decl=output.(file).ProtoA@<source>:1:10)
    (parameterized_protocol_type
      (base=protocol_type decl=output.(file).ProtoB@<source>:3:10)
      (bound_generic_struct_type decl=Swift.(file).Array
        (struct_type decl=Swift.(file).String)))))

[slavapestov]

Duplicate of #63877