Implement C++ semantics for C-style and functional-style casts. This regresses Clang extension conversions, like vectors, but allows conversions via constructors and conversion operators.

Add custom conversions to static_cast.

llvm-svn: 77076

6 files changed, 254 insertions, 17 deletions

diff --git a/clang/test/Parser/cxx-ambig-paren-expr.cpp b/clang/test/Parser/cxx-ambig-paren-expr.cpp
index 1712d849d51..324f6b5f9f8 100644
--- a/clang/test/Parser/cxx-ambig-paren-expr.cpp
+++ b/clang/test/Parser/cxx-ambig-paren-expr.cpp
@@ -5,9 +5,9 @@ void f() {
   int x, *px;
   
   // Type id.
-  (T())x;    // expected-error {{used type 'T ()'}}
-  (T())+x;   // expected-error {{used type 'T ()'}}
-  (T())*px;  // expected-error {{used type 'T ()'}}
+  (T())x;    // expected-error {{cast from 'int' to 'T ()'}}
+  (T())+x;   // expected-error {{cast from 'int' to 'T ()'}}
+  (T())*px;  // expected-error {{cast from 'int' to 'T ()'}}
   
   // Expression.
   x = (T());
diff --git a/clang/test/SemaCXX/cstyle-cast.cpp b/clang/test/SemaCXX/cstyle-cast.cpp
new file mode 100644
index 00000000000..9c47df927e7
--- /dev/null
+++ b/clang/test/SemaCXX/cstyle-cast.cpp
@@ -0,0 +1,231 @@
+// RUN: clang-cc -fsyntax-only -verify -faccess-control %s
+
+struct A {};
+
+// ----------- const_cast --------------
+
+typedef char c;
+typedef c *cp;
+typedef cp *cpp;
+typedef cpp *cppp;
+typedef cppp &cpppr;
+typedef const cppp &cpppcr;
+typedef const char cc;
+typedef cc *ccp;
+typedef volatile ccp ccvp;
+typedef ccvp *ccvpp;
+typedef const volatile ccvpp ccvpcvp;
+typedef ccvpcvp *ccvpcvpp;
+typedef int iar[100];
+typedef iar &iarr;
+typedef int (*f)(int);
+
+void t_cc()
+{
+  ccvpcvpp var = 0;
+  // Cast away deep consts and volatiles.
+  char ***var2 = (cppp)(var);
+  char ***const &var3 = var2;
+  // Const reference to reference.
+  char ***&var4 = (cpppr)(var3);
+  // Drop reference. Intentionally without qualifier change.
+  char *** var5 = (cppp)(var4);
+  const int ar[100] = {0};
+  // Array decay. Intentionally without qualifier change.
+  int *pi = (int*)(ar);
+  f fp = 0;
+  // Don't misidentify fn** as a function pointer.
+  f *fpp = (f*)(&fp);
+  int const A::* const A::*icapcap = 0;
+  int A::* A::* iapap = (int A::* A::*)(icapcap);
+}
+
+// ----------- static_cast -------------
+
+struct B : public A {};             // Single public base.
+struct C1 : public virtual B {};    // Single virtual base.
+struct C2 : public virtual B {};
+struct D : public C1, public C2 {}; // Diamond
+struct E : private A {};            // Single private base.
+struct F : public C1 {};            // Single path to B with virtual.
+struct G1 : public B {};
+struct G2 : public B {};
+struct H : public G1, public G2 {}; // Ambiguous path to B.
+
+enum Enum { En1, En2 };
+enum Onom { On1, On2 };
+
+struct Co1 { operator int(); };
+struct Co2 { Co2(int); };
+struct Co3 { };
+struct Co4 { Co4(Co3); operator Co3(); };
+
+// Explicit implicits
+void t_529_2()
+{
+  int i = 1;
+  (void)(float)(i);
+  double d = 1.0;
+  (void)(float)(d);
+  (void)(int)(d);
+  (void)(char)(i);
+  (void)(unsigned long)(i);
+  (void)(int)(En1);
+  (void)(double)(En1);
+  (void)(int&)(i);
+  (void)(const int&)(i);
+
+  int ar[1];
+  (void)(const int*)(ar);
+  (void)(void (*)())(t_529_2);
+
+  (void)(void*)(0);
+  (void)(void*)((int*)0);
+  (void)(volatile const void*)((const int*)0);
+  (void)(A*)((B*)0);
+  (void)(A&)(*((B*)0));
+  (void)(const B*)((C1*)0);
+  (void)(B&)(*((C1*)0));
+  (void)(A*)((D*)0);
+  (void)(const A&)(*((D*)0));
+  (void)(int B::*)((int A::*)0);
+  (void)(void (B::*)())((void (A::*)())0);
+  (void)(A*)((E*)0); // C-style cast ignores access control
+  (void)(void*)((const int*)0); // const_cast appended
+
+  (void)(int)(Co1());
+  (void)(Co2)(1);
+  (void)(Co3)((Co4)(Co3()));
+
+  // Bad code below
+  //(void)(A*)((H*)0); // {{static_cast from 'struct H *' to 'struct A *' is not allowed}}
+}
+
+// Anything to void
+void t_529_4()
+{
+  (void)(1);
+  (void)(t_529_4);
+}
+
+// Static downcasts
+void t_529_5_8()
+{
+  (void)(B*)((A*)0);
+  (void)(B&)(*((A*)0));
+  (void)(const G1*)((A*)0);
+  (void)(const G1&)(*((A*)0));
+  (void)(B*)((const A*)0); // const_cast appended
+  (void)(B&)(*((const A*)0)); // const_cast appended
+  (void)(E*)((A*)0); // access control ignored
+  (void)(E&)(*((A*)0)); // access control ignored
+
+  // Bad code below
+
+  (void)(C1*)((A*)0); // expected-error {{cannot cast 'struct A *' to 'struct C1 *' via virtual base 'struct B'}}
+  (void)(C1&)(*((A*)0)); // expected-error {{cannot cast 'struct A' to 'struct C1 &' via virtual base 'struct B'}}
+  (void)(D*)((A*)0); // expected-error {{cannot cast 'struct A *' to 'struct D *' via virtual base 'struct B'}}
+  (void)(D&)(*((A*)0)); // expected-error {{cannot cast 'struct A' to 'struct D &' via virtual base 'struct B'}}
+  (void)(H*)((A*)0); // expected-error {{ambiguous cast from base 'struct A' to derived 'struct H':\n    struct A -> struct B -> struct G1 -> struct H\n    struct A -> struct B -> struct G2 -> struct H}}
+  (void)(H&)(*((A*)0)); // expected-error {{ambiguous cast from base 'struct A' to derived 'struct H':\n    struct A -> struct B -> struct G1 -> struct H\n    struct A -> struct B -> struct G2 -> struct H}}
+
+  // TODO: Test DR427. This requires user-defined conversions, though.
+}
+
+// Enum conversions
+void t_529_7()
+{
+  (void)(Enum)(1);
+  (void)(Enum)(1.0);
+  (void)(Onom)(En1);
+
+  // Bad code below
+
+  (void)(Enum)((int*)0); // expected-error {{C-style cast from 'int *' to 'enum Enum' is not allowed}}
+}
+
+// Void pointer to object pointer
+void t_529_10()
+{
+  (void)(int*)((void*)0);
+  (void)(const A*)((void*)0);
+  (void)(int*)((const void*)0); // const_cast appended
+}
+
+// Member pointer upcast.
+void t_529_9()
+{
+  (void)(int A::*)((int B::*)0);
+
+  // Bad code below
+  (void)(int A::*)((int H::*)0); // expected-error {{ambiguous conversion from pointer to member of derived class 'struct H'}}
+  (void)(int A::*)((int F::*)0); // expected-error {{conversion from pointer to member of class 'struct F'}}
+}
+
+// -------- reinterpret_cast -----------
+
+enum test { testval = 1 };
+struct structure { int m; };
+typedef void (*fnptr)();
+
+// Test conversion between pointer and integral types, as in p3 and p4.
+void integral_conversion()
+{
+  void *vp = (void*)(testval);
+  long l = (long)(vp);
+  (void)(float*)(l);
+  fnptr fnp = (fnptr)(l);
+  (void)(char)(fnp); // expected-error {{cast from pointer to smaller type 'char' loses information}}
+  (void)(long)(fnp);
+}
+
+void pointer_conversion()
+{
+  int *p1 = 0;
+  float *p2 = (float*)(p1);
+  structure *p3 = (structure*)(p2);
+  typedef int **ppint;
+  ppint *deep = (ppint*)(p3);
+  (void)(fnptr*)(deep);
+}
+
+void constness()
+{
+  int ***const ipppc = 0;
+  int const *icp = (int const*)(ipppc);
+  (void)(int*)(icp); // const_cast appended
+  int const *const **icpcpp = (int const* const**)(ipppc); // const_cast appended
+  int *ip = (int*)(icpcpp);
+  (void)(int const*)(ip);
+  (void)(int const* const* const*)(ipppc);
+}
+
+void fnptrs()
+{
+  typedef int (*fnptr2)(int);
+  fnptr fp = 0;
+  (void)(fnptr2)(fp);
+  void *vp = (void*)(fp);
+  (void)(fnptr)(vp);
+}
+
+void refs()
+{
+  long l = 0;
+  char &c = (char&)(l);
+  // Bad: from rvalue
+  (void)(int&)(&c); // expected-error {{C-style cast from rvalue to reference type 'int &'}}
+}
+
+void memptrs()
+{
+  const int structure::*psi = 0;
+  (void)(const float structure::*)(psi);
+  (void)(int structure::*)(psi); // const_cast appended
+
+  void (structure::*psf)() = 0;
+  (void)(int (structure::*)())(psf);
+
+  (void)(void (structure::*)())(psi); // expected-error {{C-style cast from 'int const struct structure::*' to 'void (struct structure::*)()' is not allowed}}
+  (void)(int structure::*)(psf); // expected-error {{C-style cast from 'void (struct structure::*)()' to 'int struct structure::*' is not allowed}}
+}
diff --git a/clang/test/SemaCXX/dcl_ambig_res.cpp b/clang/test/SemaCXX/dcl_ambig_res.cpp
index c392647a3bd..495a6e6e42c 100644
--- a/clang/test/SemaCXX/dcl_ambig_res.cpp
+++ b/clang/test/SemaCXX/dcl_ambig_res.cpp
@@ -50,7 +50,7 @@ void foo5()
 void foo6() 
 { 
   (void)(int(1)); //expression 
-  (void)(int())1; // expected-error{{used type}}
+  (void)(int())1; // expected-error{{to 'int ()'}}
 } 
 
 // [dcl.ambig.res]p7:
diff --git a/clang/test/SemaCXX/decl-expr-ambiguity.cpp b/clang/test/SemaCXX/decl-expr-ambiguity.cpp
index 05e25e9bb86..1b444c16cd2 100644
--- a/clang/test/SemaCXX/decl-expr-ambiguity.cpp
+++ b/clang/test/SemaCXX/decl-expr-ambiguity.cpp
@@ -19,7 +19,7 @@ void f() {
   (int(1)); // expected-warning {{expression result unused}}
 
   // type-id
-  (int())1; // expected-error {{used type 'int ()' where arithmetic or pointer type is required}}
+  (int())1; // expected-error {{C-style cast from 'int' to 'int ()' is not allowed}}
 
   // Declarations.
   int fd(T(a)); // expected-warning {{parentheses were disambiguated as a function declarator}}
diff --git a/clang/test/SemaCXX/static-cast.cpp b/clang/test/SemaCXX/static-cast.cpp
index b5c515d5e16..8db8e33b93c 100644
--- a/clang/test/SemaCXX/static-cast.cpp
+++ b/clang/test/SemaCXX/static-cast.cpp
@@ -1,11 +1,11 @@
-// RUN: clang-cc -fsyntax-only -verify %s
+// RUN: clang-cc -fsyntax-only -verify -faccess-control %s
 
 struct A {};
 struct B : public A {};             // Single public base.
 struct C1 : public virtual B {};    // Single virtual base.
 struct C2 : public virtual B {};
 struct D : public C1, public C2 {}; // Diamond
-struct E : private A {};            // Single private base.
+struct E : private A {};            // Single private base. expected-note 2 {{'private' inheritance specifier here}}
 struct F : public C1 {};            // Single path to B with virtual.
 struct G1 : public B {};
 struct G2 : public B {};
@@ -14,6 +14,11 @@ struct H : public G1, public G2 {}; // Ambiguous path to B.
 enum Enum { En1, En2 };
 enum Onom { On1, On2 };
 
+struct Co1 { operator int(); };
+struct Co2 { Co2(int); };
+struct Co3 { };
+struct Co4 { Co4(Co3); operator Co3(); };
+
 // Explicit implicits
 void t_529_2()
 {
@@ -45,7 +50,9 @@ void t_529_2()
   (void)static_cast<int B::*>((int A::*)0);
   (void)static_cast<void (B::*)()>((void (A::*)())0);
 
-  // TODO: User-defined conversions
+  (void)static_cast<int>(Co1());
+  (void)static_cast<Co2>(1);
+  (void)static_cast<Co3>(static_cast<Co4>(Co3()));
 
   // Bad code below
 
@@ -80,11 +87,10 @@ void t_529_5_8()
   (void)static_cast<D&>(*((A*)0)); // expected-error {{cannot cast 'struct A' to 'struct D &' via virtual base 'struct B'}}
   (void)static_cast<B*>((const A*)0); // expected-error {{static_cast from 'struct A const *' to 'struct B *' casts away constness}}
   (void)static_cast<B&>(*((const A*)0)); // expected-error {{static_cast from 'struct A const' to 'struct B &' casts away constness}}
-  // Accessibility is not yet tested
-  //(void)static_cast<E*>((A*)0); // {{static_cast from 'struct A *' to 'struct E *' is not allowed}}
-  //(void)static_cast<E&>(*((A*)0)); // {{static_cast from 'struct A' to 'struct E &' is not allowed}}
-  (void)static_cast<H*>((A*)0); // expected-error {{ambiguous static_cast from base 'struct A' to derived 'struct H':\n    struct A -> struct B -> struct G1 -> struct H\n    struct A -> struct B -> struct G2 -> struct H}}
-  (void)static_cast<H&>(*((A*)0)); // expected-error {{ambiguous static_cast from base 'struct A' to derived 'struct H':\n    struct A -> struct B -> struct G1 -> struct H\n    struct A -> struct B -> struct G2 -> struct H}}
+  (void)static_cast<E*>((A*)0); // expected-error {{cannot cast 'struct A' to 'struct E' due to inaccessible}}
+  (void)static_cast<E&>(*((A*)0)); // expected-error {{cannot cast 'struct A' to 'struct E' due to inaccessible}}
+  (void)static_cast<H*>((A*)0); // expected-error {{ambiguous cast from base 'struct A' to derived 'struct H':\n    struct A -> struct B -> struct G1 -> struct H\n    struct A -> struct B -> struct G2 -> struct H}}
+  (void)static_cast<H&>(*((A*)0)); // expected-error {{ambiguous cast from base 'struct A' to derived 'struct H':\n    struct A -> struct B -> struct G1 -> struct H\n    struct A -> struct B -> struct G2 -> struct H}}
   (void)static_cast<E*>((B*)0); // expected-error {{static_cast from 'struct B *' to 'struct E *' is not allowed}}
   (void)static_cast<E&>(*((B*)0)); // expected-error {{non-const lvalue reference to type 'struct E' cannot be initialized with a value of type 'struct B'}}
 
diff --git a/clang/test/SemaTemplate/instantiate-cast.cpp b/clang/test/SemaTemplate/instantiate-cast.cpp
index d99f3e55660..d9088c8f6f8 100644
--- a/clang/test/SemaTemplate/instantiate-cast.cpp
+++ b/clang/test/SemaTemplate/instantiate-cast.cpp
@@ -1,6 +1,6 @@
 // RUN: clang-cc -fsyntax-only -verify %s
 
-struct A { int x; };
+struct A { int x; }; // expected-note 2 {{candidate}}
 
 class Base { 
 public:
@@ -23,7 +23,7 @@ struct Constructible {
 template<typename T, typename U>
 struct CStyleCast0 {
   void f(T t) {
-    (void)((U)t); // FIXME:ugly expected-error{{operand}}
+    (void)((U)t); // expected-error{{C-style cast from 'struct A' to 'int'}}
   }
 };
 
@@ -36,7 +36,7 @@ template struct CStyleCast0<A, int>; // expected-note{{instantiation}}
 template<typename T, typename U>
 struct StaticCast0 {
   void f(T t) {
-    (void)static_cast<U>(t); // expected-error{{static_cast}}
+    (void)static_cast<U>(t); // expected-error{{initialization of 'struct A'}}
   }
 };
 
@@ -89,7 +89,7 @@ template struct ConstCast0<int const *, float *>; // expected-note{{instantiatio
 template<typename T, typename U>
 struct FunctionalCast1 {
   void f(T t) {
-    (void)U(t); // FIXME:ugly expected-error{{operand}}
+    (void)U(t); // expected-error{{C-style cast from 'struct A' to 'int'}}
   }
 };