swift

720429da - [Constraint solver] Disable fallback diagnostic when error emitted into a transaction

[Constraint solver] Disable fallback diagnostic when error emitted into a transaction When we are using diagnostic transactions to disable immediate emission of diagnostics, `DiagnosticEngine::hadAnyError()` no longer accurately reports whether an error occurred. Thread the DiagnosticTransaction into the ConstraintSystem so we can also check whether it contains an error before emitting the fallback diagnostic. Fixes rdar://128272346.