Poor diagnostic for conditional expression result type error

[dabrahams]

Description

Here's a session in the repl that demonstrates

Welcome to Apple Swift version 5.8 (swiftlang-5.8.0.124.2 clang-1403.0.22.11.100).
...
  3> var a = [1]
a: [Int] = 1 value {
  [0] = 1
}
  4> a.append(true ? "yes" : "no")
expression failed to parse:
error: repl.swift:4:17: error: result values in '? :' expression have mismatching types 'String' and 'String'
a.append(true ? "yes" : "no")
                ^~~~~

Obviously the message is nonsense, and the problem is that the conditional expression is fine on its own but has the wrong type for its context.

See the first line of the repl session for version info