From 4a0ce84710b48d724e67ec29e71da5f6accf01be Mon Sep 17 00:00:00 2001
From: Hans Wennborg <hans@hanshq.net>
Date: Wed, 14 Feb 2018 09:06:43 +0000
Subject: Merging r323998:
 ------------------------------------------------------------------------
 r323998 | rsmith | 2018-02-01 21:01:49 +0100 (Thu, 01 Feb 2018) | 5 lines

PR36157: When injecting an implicit function declaration in C89, find the right
DeclContext rather than injecting it wherever we happen to be.

This avoids creating functions whose DeclContext is a struct or similar.

------------------------------------------------------------------------


git-svn-id: https://llvm.org/svn/llvm-project/cfe/branches/release_60@325104 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Sema/SemaDecl.cpp | 10 ++++++++++
 test/Sema/bitfield.c  |  4 ++++
 test/Sema/cxx-as-c.c  |  9 +++++++++
 3 files changed, 23 insertions(+)
 create mode 100644 test/Sema/cxx-as-c.c

diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 743f4bb5e8..7ca48c34e5 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -12507,10 +12507,20 @@ void Sema::ActOnFinishDelayedAttribute(Scope *S, Decl *D,
 /// call, forming a call to an implicitly defined function (per C99 6.5.1p2).
 NamedDecl *Sema::ImplicitlyDefineFunction(SourceLocation Loc,
                                           IdentifierInfo &II, Scope *S) {
+  // Find the scope in which the identifier is injected and the corresponding
+  // DeclContext.
+  // FIXME: C89 does not say what happens if there is no enclosing block scope.
+  // In that case, we inject the declaration into the translation unit scope
+  // instead.
   Scope *BlockScope = S;
   while (!BlockScope->isCompoundStmtScope() && BlockScope->getParent())
     BlockScope = BlockScope->getParent();
 
+  Scope *ContextScope = BlockScope;
+  while (!ContextScope->getEntity())
+    ContextScope = ContextScope->getParent();
+  ContextRAII SavedContext(*this, ContextScope->getEntity());
+
   // Before we produce a declaration for an implicitly defined
   // function, see whether there was a locally-scoped declaration of
   // this name as a function or variable. If so, use that
diff --git a/test/Sema/bitfield.c b/test/Sema/bitfield.c
index d625366e4e..13e9480a37 100644
--- a/test/Sema/bitfield.c
+++ b/test/Sema/bitfield.c
@@ -82,3 +82,7 @@ typedef __typeof__(+(t5.n--)) Unsigned; // also act like compound-assignment.
 struct Test6 {
   : 0.0; // expected-error{{type name requires a specifier or qualifier}}
 };
+
+struct PR36157 {
+  int n : 1 ? 1 : implicitly_declare_function(); // expected-warning {{invalid in C99}}
+};
diff --git a/test/Sema/cxx-as-c.c b/test/Sema/cxx-as-c.c
new file mode 100644
index 0000000000..41d7350d1f
--- /dev/null
+++ b/test/Sema/cxx-as-c.c
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 %s -verify
+
+// PR36157
+struct Foo {
+  Foo(int n) : n_(n) {} // expected-error 1+{{}} expected-warning 1+{{}}
+private:
+  int n;
+};
+int main() { Foo f; } // expected-error 1+{{}}
-- 
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