From 332975661d287082f64d260ef6ac5f36499d478f Mon Sep 17 00:00:00 2001
From: Douglas Gregor <dgregor@apple.com>
Date: Fri, 27 Mar 2009 04:38:56 +0000
Subject: [PATCH] Improve recovery when a constructor fails to type-check. Test
 case from Anders

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@67818 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Sema/SemaDecl.cpp                 |  2 +-
 lib/Sema/SemaDeclCXX.cpp              | 14 ++++++++------
 test/SemaCXX/constructor-recovery.cpp |  9 +++++++++
 test/SemaCXX/constructor.cpp          |  2 +-
 4 files changed, 19 insertions(+), 8 deletions(-)
 create mode 100644 test/SemaCXX/constructor-recovery.cpp

diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index e9f586583c..fa386ef68d 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -2294,7 +2294,7 @@ void Sema::AddInitializerToDecl(DeclTy *dcl, ExprArg init, bool DirectInit) {
 
         // A class is abstract if at least one function is pure virtual.
         cast<CXXRecordDecl>(CurContext)->setAbstract(true);
-      } else {
+      } else if (!Method->isInvalidDecl()) {
         Diag(Method->getLocation(), diag::err_non_virtual_pure)
           << Method->getDeclName() << Init->getSourceRange();
         Method->setInvalidDecl();
diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index bb306e4a0f..f22686020e 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -1289,20 +1289,22 @@ bool Sema::CheckConstructorDeclarator(Declarator &D, QualType &R,
 /// well-formedness, issuing any diagnostics required. Returns true if
 /// the constructor declarator is invalid.
 bool Sema::CheckConstructor(CXXConstructorDecl *Constructor) {
-  if (Constructor->isInvalidDecl())
+  CXXRecordDecl *ClassDecl 
+    = dyn_cast<CXXRecordDecl>(Constructor->getDeclContext());
+  if (!ClassDecl)
     return true;
 
-  CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(Constructor->getDeclContext());
-  bool Invalid = false;
+  bool Invalid = Constructor->isInvalidDecl();
 
   // C++ [class.copy]p3:
   //   A declaration of a constructor for a class X is ill-formed if
   //   its first parameter is of type (optionally cv-qualified) X and
   //   either there are no other parameters or else all other
   //   parameters have default arguments.
-  if ((Constructor->getNumParams() == 1) || 
-      (Constructor->getNumParams() > 1 && 
-       Constructor->getParamDecl(1)->getDefaultArg() != 0)) {
+  if (!Constructor->isInvalidDecl() &&
+      ((Constructor->getNumParams() == 1) || 
+       (Constructor->getNumParams() > 1 && 
+        Constructor->getParamDecl(1)->getDefaultArg() != 0))) {
     QualType ParamType = Constructor->getParamDecl(0)->getType();
     QualType ClassTy = Context.getTagDeclType(ClassDecl);
     if (Context.getCanonicalType(ParamType).getUnqualifiedType() == ClassTy) {
diff --git a/test/SemaCXX/constructor-recovery.cpp b/test/SemaCXX/constructor-recovery.cpp
new file mode 100644
index 0000000000..f2f9f43a10
--- /dev/null
+++ b/test/SemaCXX/constructor-recovery.cpp
@@ -0,0 +1,9 @@
+// RUN: clang-cc -fsyntax-only -verify %s
+
+struct C {
+  virtual C() = 0; // expected-error{{constructor cannot be declared 'virtual'}}
+};
+
+void f() {
+ C c;
+}
diff --git a/test/SemaCXX/constructor.cpp b/test/SemaCXX/constructor.cpp
index 4e3f4177c4..eae5146796 100644
--- a/test/SemaCXX/constructor.cpp
+++ b/test/SemaCXX/constructor.cpp
@@ -9,7 +9,7 @@ class Foo {
 
   ((Foo))(INT); // expected-error{{cannot be redeclared}}
 
-  Foo(Foo foo, int i = 17, int j = 42); // expected-error {{copy constructor must pass its first argument by reference}}
+  Foo(Foo foo, int i = 17, int j = 42); // expected-error{{copy constructor must pass its first argument by reference}}
 
   static Foo(short, short); // expected-error{{constructor cannot be declared 'static'}}
   virtual Foo(double); // expected-error{{constructor cannot be declared 'virtual'}}
-- 
2.40.0