[commit: ghc] ghc-8.6: Compiler panic on invalid syntax (unterminated pragma) (5230477)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : ghc-8.6
Link       : http://ghc.haskell.org/trac/ghc/changeset/523047768913836177f49768d1070996ebabf242/ghc

>---------------------------------------------------------------

commit 523047768913836177f49768d1070996ebabf242
Author: roland <rsx at bluewin.ch>
Date:   Tue Sep 4 14:09:20 2018 +0200

    Compiler panic on invalid syntax (unterminated pragma)
    
    Summary: After a parse error in OPTIONS_GHC issue an error message instead of a compiler panic.
    
    Test Plan: make test TEST=T15053
    
    Reviewers: Phyx, thomie, bgamari, monoidal, osa1
    
    Reviewed By: Phyx, monoidal, osa1
    
    Subscribers: tdammers, osa1, rwbarton, carter
    
    GHC Trac Issues: #15053
    
    Differential Revision: https://phabricator.haskell.org/D5093
    
    (cherry picked from commit df363a646b66f4dd13d63ec70f18e427cabc8878)


>---------------------------------------------------------------

523047768913836177f49768d1070996ebabf242
 compiler/main/HeaderInfo.hs                      | 22 ++++++++++++++++------
 testsuite/tests/parser/should_fail/T15053.stderr |  5 +++++
 testsuite/tests/parser/should_fail/all.T         |  2 +-
 3 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/compiler/main/HeaderInfo.hs b/compiler/main/HeaderInfo.hs
index 76f67b2..127cc6d 100644
--- a/compiler/main/HeaderInfo.hs
+++ b/compiler/main/HeaderInfo.hs
@@ -244,7 +244,8 @@ getOptions' dflags toks
               | IToptions_prag str <- getToken open
               , ITclose_prag       <- getToken close
               = case toArgs str of
-                  Left err -> panic ("getOptions'.parseToks: " ++ err)
+                  Left _err -> optionsParseError str dflags $   -- #15053
+                                 combineSrcSpans (getLoc open) (getLoc close)
                   Right args -> map (L (getLoc open)) args ++ parseToks xs
           parseToks (open:close:xs)
               | ITinclude_prag str <- getToken open
@@ -314,17 +315,15 @@ checkExtension dflags (L l ext)
 
 languagePragParseError :: DynFlags -> SrcSpan -> a
 languagePragParseError dflags loc =
-  throw $ mkSrcErr $ unitBag $
-     (mkPlainErrMsg dflags loc $
+    throwErr dflags loc $
        vcat [ text "Cannot parse LANGUAGE pragma"
             , text "Expecting comma-separated list of language options,"
             , text "each starting with a capital letter"
-            , nest 2 (text "E.g. {-# LANGUAGE TemplateHaskell, GADTs #-}") ])
+            , nest 2 (text "E.g. {-# LANGUAGE TemplateHaskell, GADTs #-}") ]
 
 unsupportedExtnError :: DynFlags -> SrcSpan -> String -> a
 unsupportedExtnError dflags loc unsup =
-  throw $ mkSrcErr $ unitBag $
-    mkPlainErrMsg dflags loc $
+    throwErr dflags loc $
         text "Unsupported extension: " <> text unsup $$
         if null suggestions then Outputable.empty else text "Perhaps you meant" <+> quotedListWithOr (map text suggestions)
   where
@@ -340,3 +339,14 @@ optionsErrorMsgs dflags unhandled_flags flags_lines _filename
             ErrUtils.mkPlainErrMsg dflags flagSpan $
                     text "unknown flag in  {-# OPTIONS_GHC #-} pragma:" <+> text flag
 
+optionsParseError :: String -> DynFlags -> SrcSpan -> a     -- #15053
+optionsParseError str dflags loc =
+  throwErr dflags loc $
+      vcat [ text "Error while parsing OPTIONS_GHC pragma."
+           , text "Expecting whitespace-separated list of GHC options."
+           , text "  E.g. {-# OPTIONS_GHC -Wall -O2 #-}"
+           , text ("Input was: " ++ show str) ]
+
+throwErr :: DynFlags -> SrcSpan -> SDoc -> a                -- #15053
+throwErr dflags loc doc =
+  throw $ mkSrcErr $ unitBag $ mkPlainErrMsg dflags loc doc
diff --git a/testsuite/tests/parser/should_fail/T15053.stderr b/testsuite/tests/parser/should_fail/T15053.stderr
new file mode 100644
index 0000000..0544327
--- /dev/null
+++ b/testsuite/tests/parser/should_fail/T15053.stderr
@@ -0,0 +1,5 @@
+T15053.hs:1:16:
+    Error while parsing OPTIONS_GHC pragma.
+    Expecting whitespace-separated list of GHC options.
+      E.g. {-# OPTIONS_GHC -Wall -O2 #-}
+    Input was: " -O1 }/n/"/n  "
diff --git a/testsuite/tests/parser/should_fail/all.T b/testsuite/tests/parser/should_fail/all.T
index 93d0e0a..cf1202f 100644
--- a/testsuite/tests/parser/should_fail/all.T
+++ b/testsuite/tests/parser/should_fail/all.T
@@ -125,4 +125,4 @@ test('typeops_A', normal, compile_fail, [''])
 test('typeops_B', normal, compile_fail, [''])
 test('typeops_C', normal, compile_fail, [''])
 test('typeops_D', normal, compile_fail, [''])
-test('T15053', expect_broken(15053), compile_fail, ['']) # shouldn't panic
+test('T15053', normal, compile_fail, [''])