[project @ 2003-02-12 15:01:31 by simonpj]

[ghc-hetmet.git] / ghc / compiler / typecheck / TcRnDriver.lhs

diff --git a/ghc/compiler/typecheck/TcRnDriver.lhs b/ghc/compiler/typecheck/TcRnDriver.lhs
index 2a0568a..d225b6c 100644 (file)
--- a/ghc/compiler/typecheck/TcRnDriver.lhs
+++ b/ghc/compiler/typecheck/TcRnDriver.lhs
@@ -57,8 +57,7 @@ import Inst           ( showLIE )
 import TcBinds         ( tcTopBinds )
 import TcClassDcl      ( tcClassDecls2 )
 import TcDefaults      ( tcDefaults )
-import TcEnv           ( RecTcGblEnv, 
-                         tcExtendGlobalValEnv, 
+import TcEnv           ( tcExtendGlobalValEnv, 
                          tcExtendGlobalEnv,
                          tcExtendInstEnv, tcExtendRules,
                          tcLookupTyCon, tcLookupGlobal,
@@ -747,6 +746,7 @@ tc_src_decls
                   hs_ruleds = rule_decls,
                   hs_valds  = val_binds })
  = do {                -- Type-check the type and class decls, and all imported decls
+               -- The latter come in via tycl_decls
         traceTc (text "Tc2") ;
        tcg_env <- tcTyClDecls tycl_decls ;
        setGblEnv tcg_env       $ do {
@@ -830,8 +830,9 @@ tcTyClDecls tycl_decls
        -- an error we'd better stop now, to avoid a cascade
        
     traceTc (text "TyCl1")             `thenM_`
-    tcTyAndClassDecls tycl_decls       `thenM` \ tycl_things ->
-    tcExtendGlobalEnv tycl_things      $
+    tcTyAndClassDecls tycl_decls       `thenM` \ tcg_env ->
+       -- Returns the extended environment
+    setGblEnv tcg_env                  $
 
     traceTc (text "TyCl2")             `thenM_`
     tcInterfaceSigs tycl_decls         `thenM` \ tcg_env ->
@@ -931,8 +932,8 @@ typecheckIfaceDecls :: HsGroup Name -> TcM TcGblEnv
   -- That is why the tcExtendX functions need to do partitioning.
   --
   -- If all the decls are from other modules, the returned TcGblEnv
-  -- will have an empty tc_genv, but its tc_inst_env and tc_ist 
-  -- caches may have been augmented.
+  -- will have an empty tc_genv, but its tc_inst_env
+  -- cache may have been augmented.
 typecheckIfaceDecls (HsGroup { hs_tyclds = tycl_decls,
                               hs_instds = inst_decls,
                               hs_ruleds = rule_decls })
@@ -1078,14 +1079,16 @@ check_main ghci_mode tcg_env
  | mod_name /= mAIN_Name
  = return (tcg_env, emptyFVs)
 
+       -- Check that 'main' is in scope
+       -- It might be imported from another module!
+       -- 
+       -- We use a guard for this (rather than letting lookupSrcName fail)
+       -- because it's not an error in ghci)
  | not (main_RDR_Unqual `elemRdrEnv` rdr_env)
  = do { complain_no_main; return (tcg_env, emptyFVs) }
 
  | otherwise
- = do {        -- Check that 'main' is in scope
-               -- It might be imported from another module!
-       main_name <- lookupSrcName main_RDR_Unqual ;
-       failIfErrsM ;
+ = do { main_name <- lookupSrcName main_RDR_Unqual ;
 
        tcg_env <- importSupportingDecls (unitFV runIOName) ;
        setGblEnv tcg_env $ do {
@@ -1116,8 +1119,10 @@ check_main ghci_mode tcg_env
     rdr_env  = tcg_rdr_env tcg_env
  
     complain_no_main | ghci_mode == Interactive = return ()
-                    | otherwise                = addErr noMainMsg
+                    | otherwise                = failWithTc noMainMsg
        -- In interactive mode, don't worry about the absence of 'main'
+       -- In other modes, fail altogether, so that we don't go on
+       -- and complain a second time when processing the export list.
 
     mainCtxt  = ptext SLIT("When checking the type of 'main'")
     noMainMsg = ptext SLIT("No 'main' defined in module Main")