Avoid comparing ‘SourceText’ when comparing ASTs

data/examples/declaration/instance/overlappable-instances-out.hs

@@ -1,8 +1,3 @@
--- Test should have tested different whitespaces inside pragma. However, the
--- pragmas contain a "SourceText" which compares as equal only if the whitespace
--- inside the pragma is printed exactly identically (i.e. including newlines and
--- all.) In practice, removing this whitespace is desirable, so whitespace is
--- not varied to avoid spurious and difficult-to-avoid test case errors.
 instance {-# OVERLAPPABLE #-} Eq Int where
   (==) _ _ = False
 

data/examples/declaration/instance/overlappable-instances.hs

@@ -1,17 +1,11 @@
--- Test should have tested different whitespaces inside pragma. However, the
--- pragmas contain a "SourceText" which compares as equal only if the whitespace
--- inside the pragma is printed exactly identically (i.e. including newlines and
--- all.) In practice, removing this whitespace is desirable, so whitespace is
--- not varied to avoid spurious and difficult-to-avoid test case errors.
-
-instance {-# OVERLAPPABLE #-} Eq Int where (==) _ _ = False
+instance {-# OVERLAPPABLE   #-} Eq Int where (==) _ _ = False
 
 instance
-    {-# OVERLAPPING #-} Ord Int where compare _ _ = GT
+    {-#   OVERLAPPING #-} Ord Int where compare _ _ = GT
 
-instance {-# OVERLAPS #-} Eq Double where
+instance {-#  OVERLAPS  #-} Eq Double where
     (==) _ _ = False
 
 instance
-    {-# INCOHERENT #-} Ord Double where
+    {-# INCOHERENT  #-} Ord Double where
     compare _ _ = GT

src/Ormolu/Diff.hs

@@ -9,6 +9,7 @@ module Ormolu.Diff
   )
 where
 
+import BasicTypes (SourceText)
 import Data.Generics
 import GHC
 import Ormolu.CommentStream
@@ -33,7 +34,10 @@ matchIgnoringSrcSpans = genericQuery
   where
     genericQuery :: GenericQ (GenericQ Bool)
     genericQuery x y = (toConstr x == toConstr y)
-      && and (gzipWithQ (genericQuery `extQ` srcSpanEq `extQ` hsModuleEq) x y)
+      && and (gzipWithQ (genericQuery
+                           `extQ` srcSpanEq
+                           `extQ` hsModuleEq
+                           `extQ` sourceTextEq) x y)
 
     srcSpanEq :: SrcSpan -> GenericQ Bool
     srcSpanEq _ _ = True
@@ -46,3 +50,6 @@ matchIgnoringSrcSpans = genericQuery
           matchIgnoringSrcSpans
             hs0 { hsmodImports = sortImports (hsmodImports hs0) }
             hs1 { hsmodImports = sortImports (hsmodImports hs1) }
+
+    sourceTextEq :: SourceText -> GenericQ Bool
+    sourceTextEq _ _ = True