Allow configuration of error message printing

This MR implements the idea of #21731 that the printing of a diagnostic
method should be configurable at the printing time.

The interface of the `Diagnostic` class is modified from:

```
class Diagnostic a where
  diagnosticMessage :: a -> DecoratedSDoc
  diagnosticReason  :: a -> DiagnosticReason
  diagnosticHints   :: a -> [GhcHint]
```

to

```
class Diagnostic a where
  type DiagnosticOpts a
  defaultDiagnosticOpts :: DiagnosticOpts a
  diagnosticMessage :: DiagnosticOpts a -> a -> DecoratedSDoc
  diagnosticReason  :: a -> DiagnosticReason
  diagnosticHints   :: a -> [GhcHint]
```

and so each `Diagnostic` can implement their own configuration record
which can then be supplied by a client in order to dictate how to print
out the error message.

At the moment this only allows us to implement #21722 nicely but in
future it is more natural to separate the configuration of how much
information we put into an error message and how much we decide to print
out of it.

Updates Haddock submodule

2 files changed, 5 insertions, 3 deletions

diff --git a/testsuite/tests/ghc-api/T18522-dbg-ppr.hs b/testsuite/tests/ghc-api/T18522-dbg-ppr.hs
index 8e89a63cc6..32bad7c8e0 100644
--- a/testsuite/tests/ghc-api/T18522-dbg-ppr.hs
+++ b/testsuite/tests/ghc-api/T18522-dbg-ppr.hs
@@ -51,7 +51,8 @@ main = do
       case mres of
         Nothing -> do
           let diag_opts = initDiagOpts dflags
-          printMessages logger diag_opts warnings
-          printMessages logger diag_opts errors
+              print_config = initTcMessageOpts dflags
+          printMessages logger print_config diag_opts warnings
+          printMessages logger print_config diag_opts errors
         Just (t, _) -> do
           putStrLn $ showSDoc dflags (debugPprType t)
diff --git a/testsuite/tests/regalloc/regalloc_unit_tests.hs b/testsuite/tests/regalloc/regalloc_unit_tests.hs
index 0238b5d03c..f3294bfd35 100644
--- a/testsuite/tests/regalloc/regalloc_unit_tests.hs
+++ b/testsuite/tests/regalloc/regalloc_unit_tests.hs
@@ -140,7 +140,8 @@ compileCmmForRegAllocStats logger home_unit dflags cmmFile ncgImplF us = do
 
     -- print parser errors or warnings
     let !diag_opts = initDiagOpts dflags
-    mapM_ (printMessages logger diag_opts) [warnings, errors]
+        !print_config = initPsMessageOpts dflags
+    mapM_ (printMessages logger print_config diag_opts) [warnings, errors]
 
     let initTopSRT = emptySRT thisMod
     cmmGroup <- fmap snd $ cmmPipeline logger cmm_config initTopSRT $ fst $ fromJust parsedCmm