re-add file

Author: stephenjudkins

src/Hint/PatternWildCard.hs

@@ -0,0 +1,33 @@
+{-
+    Warn against wildcards in pattern
+
+<TEST>
+foo (case x of { Foo _ -> spam }) -- @Ignore ???
+case x of { Foo (Spam (Eggs _)) -> spam } -- @Ignore ???
+case x of { Foo _ -> spam } -- @Ignore ???
+case x of { Foo bar -> spam }
+foo (case x of { Foo bar -> spam })
+</TEST>
+-}
+
+module Hint.PatternWildCard (patternWildCardHint)
+where
+
+import Hint.Type (DeclHint, ignoreNoSuggestion, Idea)
+import GHC.Hs
+import GHC.Types.SrcLoc
+import Data.Generics.Uniplate.DataOnly
+
+patternWildCardHint :: DeclHint
+patternWildCardHint _ _ code = concatMap inspectCode $ childrenBi code
+
+inspectCode :: LHsExpr GhcPs -> [Idea]
+inspectCode (L _ ((HsCase _ _ (MG _ (L _ cases) _)))) = concatMap inspectCase cases
+inspectCode o = concatMap inspectCode $ children o
+
+inspectCase :: LMatch GhcPs (LHsExpr GhcPs) -> [Idea]
+inspectCase c@(L _ (Match _ _ pats _)) = concatMap inspectPat pats
+
+inspectPat :: LPat GhcPs -> [Idea]
+inspectPat c@(L _ (WildPat _)) = [ignoreNoSuggestion "Don't use wildcard in pattern match" (reLoc c)]
+inspectPat o = concatMap inspectPat $ children o