From df2a91063907ae160bde4e07fe0bb82f1ea9a3e1 Mon Sep 17 00:00:00 2001
From: peter klausler <pklausler@nvidia.com>
Date: Thu, 14 Mar 2019 14:51:40 -0700
Subject: [PATCH] [flang] Get clean -fparse-only pass over WRF

Original-commit: flang-compiler/f18@ffe517abc6bdc481248308156dec6d48089e8269
Reviewed-on: https://github.com/flang-compiler/f18/pull/333
---
 flang/documentation/Extensions.md | 2 ++
 flang/lib/parser/features.h       | 3 ++-
 flang/lib/parser/grammar.h        | 3 ++-
 flang/lib/parser/prescan.cc       | 5 +++--
 4 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/flang/documentation/Extensions.md b/flang/documentation/Extensions.md
index 38fccff..88c0b3e3 100644
--- a/flang/documentation/Extensions.md
+++ b/flang/documentation/Extensions.md
@@ -56,6 +56,8 @@ Extensions, deletions, and legacy features supported by default
 * Character literals as elements of an array constructor without an explicit
   type specifier need not have the same length; the longest literal determines
   the length parameter of the implicit type, not the first.
+* Outside a character literal, a comment after a continuation marker (&)
+  need not begin with a comment marker (!).
 
 Extensions supported when enabled by options
 --------------------------------------------
diff --git a/flang/lib/parser/features.h b/flang/lib/parser/features.h
index 7b8136d..d971fdb 100644
--- a/flang/lib/parser/features.h
+++ b/flang/lib/parser/features.h
@@ -29,7 +29,8 @@ ENUM_CLASS(LanguageFeature, BackslashEscapes, OldDebugLines,
     OldStyleParameter, ComplexConstructor, PercentLOC, SignedPrimary, FileName,
     Convert, Dispose, IOListLeadingComma, AbbreviatedEditDescriptor,
     ProgramParentheses, PercentRefAndVal, OmitFunctionDummies, CrayPointer,
-    Hollerith, ArithmeticIF, Assign, AssignedGOTO, Pause, OpenMP)
+    Hollerith, ArithmeticIF, Assign, AssignedGOTO, Pause, OpenMP,
+    CruftAfterAmpersand)
 
 using LanguageFeatures =
     common::EnumSet<LanguageFeature, LanguageFeature_enumSize>;
diff --git a/flang/lib/parser/grammar.h b/flang/lib/parser/grammar.h
index c75958d..7df25e7 100644
--- a/flang/lib/parser/grammar.h
+++ b/flang/lib/parser/grammar.h
@@ -3092,7 +3092,8 @@ TYPE_PARSER(construct<UseStmt>("USE" >> optionalBeforeColons(moduleNature),
                 name, ", ONLY :" >> optionalList(Parser<Only>{})) ||
     construct<UseStmt>("USE" >> optionalBeforeColons(moduleNature), name,
         defaulted("," >>
-            nonemptyList("expected renamings"_err_en_US, Parser<Rename>{}))))
+            nonemptyList("expected renamings"_err_en_US, Parser<Rename>{})) /
+            lookAhead(endOfStmt)))
 
 // R1411 rename ->
 //         local-name => use-name |
diff --git a/flang/lib/parser/prescan.cc b/flang/lib/parser/prescan.cc
index 92768fa..2e1c69e 100644
--- a/flang/lib/parser/prescan.cc
+++ b/flang/lib/parser/prescan.cc
@@ -853,8 +853,9 @@ bool Prescanner::FreeFormContinuation() {
   if (*p != '\n') {
     if (inCharLiteral_) {
       return false;
-    } else if (*p != '!') {
-      Say(GetProvenance(p), "treated as comment after &"_en_US);
+    } else if (*p != '!' &&
+        features_.ShouldWarn(LanguageFeature::CruftAfterAmpersand)) {
+      Say(GetProvenance(p), "missing ! before comment after &"_en_US);
     }
   }
   do {
-- 
2.7.4