From 51fe22391654cf6eb3a054e48a9c3a3c599911b2 Mon Sep 17 00:00:00 2001
From: Tim Keith <tkeith@nvidia.com>
Date: Mon, 26 Aug 2019 15:46:49 -0700
Subject: [PATCH] [flang] Fix bug with statement functions

When the name of a statement function was previously declared, we
weren't correctly recognizing it as a statement function. E.g.
```
integer :: f, i
f(i) = i + 1
```

`f` was entered in the symbol table with `EntityDetails` and the
`parser::Name` on the first line was resolved to that symbol.
On the second line we replaced the symbol for `f` in the scope
with a subprogram symbol, but that didn't change the symbol in
the first `parser::Name`.

The fix requires:
1. don't erase the original symbol for `f`, just replace its details
2. when we erase the symbol for `f` in the subprogram scope, don't
   unresolve it

Original-commit: flang-compiler/f18@31212686ea357503840c0562853c6977bfc1ffe5
---
 flang/lib/semantics/resolve-names.cc |  4 ++--
 flang/test/semantics/CMakeLists.txt  |  1 +
 flang/test/semantics/symbol16.f90    | 30 ++++++++++++++++++++++++++++++
 3 files changed, 33 insertions(+), 2 deletions(-)
 create mode 100644 flang/test/semantics/symbol16.f90

diff --git a/flang/lib/semantics/resolve-names.cc b/flang/lib/semantics/resolve-names.cc
index 8ea3d12..1435cdc 100644
--- a/flang/lib/semantics/resolve-names.cc
+++ b/flang/lib/semantics/resolve-names.cc
@@ -2353,7 +2353,7 @@ bool SubprogramVisitor::HandleStmtFunction(const parser::StmtFunctionStmt &x) {
     }
     // TODO: check that attrs are compatible with stmt func
     resultType = details->type();
-    EraseSymbol(name);
+    symbol->details() = UnknownDetails{};  // will be replaced below
   }
   if (badStmtFuncFound_) {
     Say(name, "'%s' has not been declared as an array"_err_en_US);
@@ -2372,7 +2372,7 @@ bool SubprogramVisitor::HandleStmtFunction(const parser::StmtFunctionStmt &x) {
     }
     details.add_dummyArg(MakeSymbol(dummyName, std::move(dummyDetails)));
   }
-  EraseSymbol(name);  // added by PushSubprogramScope
+  EraseSymbol(symbol);  // added by PushSubprogramScope
   EntityDetails resultDetails;
   if (resultType) {
     resultDetails.set_type(*resultType);
diff --git a/flang/test/semantics/CMakeLists.txt b/flang/test/semantics/CMakeLists.txt
index 5626ad2..5675526 100644
--- a/flang/test/semantics/CMakeLists.txt
+++ b/flang/test/semantics/CMakeLists.txt
@@ -177,6 +177,7 @@ set(SYMBOL_TESTS
   symbol13.f90
   symbol14.f90
   symbol15.f90
+  symbol16.f90
   kinds01.f90
   kinds03.f90
   procinterface01.f90
diff --git a/flang/test/semantics/symbol16.f90 b/flang/test/semantics/symbol16.f90
new file mode 100644
index 0000000..d6785f3
--- /dev/null
+++ b/flang/test/semantics/symbol16.f90
@@ -0,0 +1,30 @@
+! Copyright (c) 2019, NVIDIA CORPORATION.  All rights reserved.
+!
+! Licensed under the Apache License, Version 2.0 (the "License");
+! you may not use this file except in compliance with the License.
+! You may obtain a copy of the License at
+!
+!     http://www.apache.org/licenses/LICENSE-2.0
+!
+! Unless required by applicable law or agreed to in writing, software
+! distributed under the License is distributed on an "AS IS" BASIS,
+! WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+! See the License for the specific language governing permissions and
+! limitations under the License.
+
+! Statement functions
+
+!DEF: /p1 MainProgram
+program p1
+ !DEF: /p1/f Subprogram INTEGER(4)
+ !DEF: /p1/i ObjectEntity INTEGER(4)
+ !DEF: /p1/j ObjectEntity INTEGER(4)
+ integer f, i, j
+ !REF: /p1/f
+ !REF: /p1/i
+ !DEF: /p1/f/i ObjectEntity INTEGER(4)
+ f(i) = i + 1
+ !REF: /p1/j
+ !REF: /p1/f
+ j = f(2)
+end program
-- 
2.7.4