Swift cannot deduce thrown Error type when parameter closure throws the same error type as the calling function

[elijah-semyonov]

Description

The snippet in Reproduction doesn't compile.

Reproduction

Compiles:

struct SomeError: Error {
    
}

func perform<T>(
    block: () throws -> T
) throws -> T {
    try block()
}


let a: Int = try perform { 
    throw SomeError()
}

Doesn't compile:

struct SomeError: Error {
    
}

func perform<T>(
    block: () throws(SomeError) -> T
) throws(SomeError) -> T {
    try block()
}


let a: Int = try perform { // Invalid conversion of thrown error type 'any Error' to 'SomeError'

    throw SomeError()
}

Expected behavior

Compiler should deduce that error thrown by the closure is the same kind of error and successfully compile the program.

Environment

swift-driver version: 1.120.5 Apple Swift version 6.1 (swiftlang-6.1.0.110.21 clang-1700.0.13.3)
Target: arm64-apple-macosx15.0

Additional information

No response