[project @ 2005-11-02 17:41:00 by simonpj]

Second correction to the TH fix of Oct 26, involving thFAKE

Original message
  1) A bug in the renaming of [d| brackets |]. The problem was
  that when we renamed the bracket we messed up the name cache, because
  the module was still that of the parent module. Now we set a fake
  module before renaming it.

This commit fixes the typecheker problem in a different way,
in tcLookupGlobal.

ghc/compiler/typecheck/TcEnv.lhs

@@ -63,7 +63,8 @@ import InstEnv		( Instance, DFunId, instanceDFunId, instanceHead )
 import DataCon		( DataCon )
 import TyCon		( TyCon )
 import Class		( Class )
-import Name		( Name, NamedThing(..), getSrcLoc, nameIsLocalOrFrom )
+import Name		( Name, NamedThing(..), getSrcLoc, nameModule )
+import PrelNames	( thFAKE )
 import NameEnv
 import OccName		( mkDFunOcc, occNameString )
 import HscTypes		( extendTypeEnvList, lookupType,
@@ -93,20 +94,29 @@ tcLookupLocatedGlobal name
 
 tcLookupGlobal :: Name -> TcM TyThing
 tcLookupGlobal name
-  = do	{ env <- getGblEnv
-	; if nameIsLocalOrFrom (tcg_mod env) name
-
-	  then	-- It's defined in this module
-	      case lookupNameEnv (tcg_type_env env) name of
-		Just thing -> return thing
-		Nothing	   -> notFound  name	-- Panic!
+  = ASSERT( isGlobalName name )
+    do	{ env <- getGblEnv
+	
+		-- Try local envt
+	; case lookupNameEnv (tcg_type_env env) name of {
+		Just thing -> return thing ;
+		Nothing	   -> do 
 	 
-	  else do 		-- It's imported
+		-- Try global envt
 	{ (eps,hpt) <- getEpsAndHpt
-	; case lookupType hpt (eps_PTE eps) name of 
-	    Just thing -> return thing 
-	    Nothing    -> tcImportDecl name
-    }}
+	; case lookupType hpt (eps_PTE eps) name of  {
+	    Just thing -> return thing ;
+	    Nothing    -> do
+
+		-- Should it have been in the local envt?
+	{ let mod = nameModule name
+	; if mod == tcg_mod env || mod == thFAKE then
+		notFound name	-- It should be local, so panic
+				-- The thFAKE possibility is because it
+				-- might be in a declaration bracket
+	  else
+		tcImportDecl name	-- Go find it in an interface
+	}}}}}
 
 tcLookupGlobalId :: Name -> TcM Id
 -- Never used for Haskell-source DataCons, hence no ADataCon case

ghc/compiler/typecheck/TcSplice.lhs

@@ -140,13 +140,9 @@ tc_bracket (TypBr typ)
 	-- Result type is Type (= Q Typ)
 
 tc_bracket (DecBr decls)
-  = do	{ setModule thFAKE $ tcTopSrcDecls emptyModDetails decls
+  = do	{  tcTopSrcDecls emptyModDetails decls
 	-- Typecheck the declarations, dicarding the result
 	-- We'll get all that stuff later, when we splice it in
-	-- See comments with RnExpr.rnBracket for the thFAKE stuff;
-	--	the type checker uses the module name to decide which
-	--	names are local (and hence can be found in the local
-	--	type envt), so we do need to set the module here too.
 
 	; decl_ty <- tcMetaTy decTyConName
 	; q_ty    <- tcMetaTy qTyConName