testsuite: fix T23540 fragility on 32-bit platforms

T23540 is fragile on 32-bit platforms. The root cause is usage of
`getEvidenceTreesAtPoint`, which internally relies on `Name`'s `Ord`
instance, which is indeterministic. The solution is adding a
deterministic `Ord` instance for `EvidenceInfo` and sorting the
evidence trees before pretty printing. Fixes #24449.

compiler/GHC/Iface/Ext/Utils.hs

@@ -107,7 +107,13 @@ data EvidenceInfo a
   , evidenceSpan :: RealSrcSpan
   , evidenceType :: a
   , evidenceDetails :: Maybe (EvVarSource, Scope, Maybe Span)
-  } deriving (Eq,Ord,Functor)
+  } deriving (Eq, Functor)
+
+instance Ord a => Ord (EvidenceInfo a) where
+  compare (EvidenceInfo name span typ dets) (EvidenceInfo name' span' typ' dets') =
+    case stableNameCmp name name' of
+      EQ -> compare (span, typ, dets) (span', typ', dets')
+      r -> r
 
 instance (Outputable a) => Outputable (EvidenceInfo a) where
   ppr (EvidenceInfo name span typ dets) =

testsuite/tests/hiefile/should_run/T23540.stdout

@@ -124,35 +124,35 @@ At point (49,14), we found:
 At point (61,7), we found:
 ==========================
 ┌
-│ $dFunctor at T23540.hs:1:1, of type: Functor Identity'
-│     is an evidence variable bound by a let, depending on: [$fFunctorIdentity']
+│ $dApplicative at T23540.hs:1:1, of type: Applicative Identity'
+│     is an evidence variable bound by a let, depending on: [$fApplicativeIdentity']
 │           with scope: ModuleScope
 │           
 │     Defined at <no location info>
 └
 |
 `- ┌
-   │ $fFunctorIdentity' at T23540.hs:54:10-26, of type: Functor Identity'
-   │     is an evidence variable bound by an instance of class Functor
+   │ $fApplicativeIdentity' at T23540.hs:56:10-30, of type: Applicative Identity'
+   │     is an evidence variable bound by an instance of class Applicative
    │           with scope: ModuleScope
    │           
-   │     Defined at T23540.hs:54:10
+   │     Defined at T23540.hs:56:10
    └
 
 ┌
-│ $dApplicative at T23540.hs:1:1, of type: Applicative Identity'
-│     is an evidence variable bound by a let, depending on: [$fApplicativeIdentity']
+│ $dFunctor at T23540.hs:1:1, of type: Functor Identity'
+│     is an evidence variable bound by a let, depending on: [$fFunctorIdentity']
 │           with scope: ModuleScope
 │           
 │     Defined at <no location info>
 └
 |
 `- ┌
-   │ $fApplicativeIdentity' at T23540.hs:56:10-30, of type: Applicative Identity'
-   │     is an evidence variable bound by an instance of class Applicative
+   │ $fFunctorIdentity' at T23540.hs:54:10-26, of type: Functor Identity'
+   │     is an evidence variable bound by an instance of class Functor
    │           with scope: ModuleScope
    │           
-   │     Defined at T23540.hs:56:10
+   │     Defined at T23540.hs:54:10
    └
 
 ==========================
@@ -202,33 +202,34 @@ At point (69,4), we found:
 At point (82,6), we found:
 ==========================
 ┌
-│ $dOrd at T23540.hs:1:1, of type: Ord Modulo1
-│     is an evidence variable bound by a let, depending on: [$fOrdModulo1]
+│ $dNum at T23540.hs:1:1, of type: Num Modulo1
+│     is an evidence variable bound by a let, depending on: [$fNumModulo1]
 │           with scope: ModuleScope
 │           
 │     Defined at <no location info>
 └
 |
 `- ┌
-   │ $fOrdModulo1 at T23540.hs:8:35-37, of type: Ord Modulo1
-   │     is an evidence variable bound by an instance of class Ord
+   │ $fNumModulo1 at T23540.hs:10:10-20, of type: Num Modulo1
+   │     is an evidence variable bound by an instance of class Num
    │           with scope: ModuleScope
    │           
-   │     Defined at T23540.hs:8:35
+   │     Defined at T23540.hs:10:10
    └
 
 ┌
-│ $dNum at T23540.hs:1:1, of type: Num Modulo1
-│     is an evidence variable bound by a let, depending on: [$fNumModulo1]
+│ $dOrd at T23540.hs:1:1, of type: Ord Modulo1
+│     is an evidence variable bound by a let, depending on: [$fOrdModulo1]
 │           with scope: ModuleScope
 │           
 │     Defined at <no location info>
 └
 |
 `- ┌
-   │ $fNumModulo1 at T23540.hs:10:10-20, of type: Num Modulo1
-   │     is an evidence variable bound by an instance of class Num
+   │ $fOrdModulo1 at T23540.hs:8:35-37, of type: Ord Modulo1
+   │     is an evidence variable bound by an instance of class Ord
    │           with scope: ModuleScope
    │           
-   │     Defined at T23540.hs:10:10
-   └
\ No newline at end of file
+   │     Defined at T23540.hs:8:35
+   └
+

testsuite/tests/hiefile/should_run/TestUtils.hs

@@ -10,6 +10,7 @@ module TestUtils
   ) where
 
 import System.Environment
+import Data.List (sort)
 import Data.Tree
 import GHC.Types.Name.Cache
 import GHC.Types.SrcLoc
@@ -20,13 +21,13 @@ import qualified GHC.Utils.Outputable as O
 import GHC.Iface.Ext.Binary
 import GHC.Iface.Ext.Types
 import GHC.Iface.Ext.Utils
- 
+
 import GHC.Driver.Session
 import GHC.SysTools
 
 makeNc :: IO NameCache
 makeNc = initNameCache 'z' []
- 
+
 dynFlagsForPrinting :: String -> IO DynFlags
 dynFlagsForPrinting libdir = do
   systemSettings <- initSysTools libdir
@@ -53,7 +54,7 @@ explainEv df hf refmap point = do
   putStrLn $ replicate 26 '='
   putStr $ drawForest ptrees
   where
-    trees = getEvidenceTreesAtPoint hf refmap point
+    trees = sort $ getEvidenceTreesAtPoint hf refmap point
 
     ptrees = fmap (pprint . fmap expandType) <$> trees
 

testsuite/tests/hiefile/should_run/all.T

@@ -5,5 +5,5 @@ test('T23492', [extra_run_opts('"' + config.libdir + '"'), extra_files(['TestUti
 test('RecordDotTypes', [extra_run_opts('"' + config.libdir + '"'), extra_files(['TestUtils.hs'])], compile_and_run, ['-package ghc -fwrite-ide-info'])
 test('SpliceTypes', [req_th, extra_run_opts('"' + config.libdir + '"'), extra_files(['TestUtils.hs'])], compile_and_run, ['-package ghc -fwrite-ide-info'])
 test('HieVdq', [extra_run_opts('"' + config.libdir + '"'), extra_files(['TestUtils.hs'])], compile_and_run, ['-package ghc -fwrite-ide-info'])
-test('T23540', [extra_run_opts('"' + config.libdir + '"'), extra_files(['TestUtils.hs']), when(arch('i386'), fragile(24449))], compile_and_run, ['-package ghc -fwrite-ide-info'])
+test('T23540', [extra_run_opts('"' + config.libdir + '"'), extra_files(['TestUtils.hs'])], compile_and_run, ['-package ghc -fwrite-ide-info'])
 test('T23120', [extra_run_opts('"' + config.libdir + '"'), extra_files(['TestUtils.hs'])], compile_and_run, ['-package ghc -fwrite-ide-info'])