making contracts on virtual functions invalid

Author: NinaRanns

gcc/cp/class.cc

@@ -3225,6 +3225,14 @@ check_for_override (tree decl, tree ctype)
 
       if (DECL_DESTRUCTOR_P (decl))
 	TYPE_HAS_NONTRIVIAL_DESTRUCTOR (ctype) = true;
+
+      if (DECL_HAS_CONTRACTS_P(decl)
+	  && flag_contract_nonattr_inheritance_mode
+	      == CONTRACT_INHERITANCE_NONE)
+	{
+	  error_at (DECL_SOURCE_LOCATION(decl),
+		    "Contracts can not be added to virtual functions.");
+	}
     }
   else if (DECL_FINAL_P (decl))
     error ("%q+#D marked %<final%>, but is not virtual", decl);

gcc/cp/search.cc

@@ -2230,15 +2230,15 @@ check_override_contracts (tree fndecl)
 {
 
   if (!flag_contracts || !flag_contracts_nonattr
-      || flag_contract_nonattr_inheritance_mode != CONTRACT_INHERITANCE_P3653 )
+      || flag_contract_nonattr_inheritance_mode != CONTRACT_INHERITANCE_P3653)
     return;
 
   /* A constructor for a class T does not override a function T
-     in a base class.  */
+   in a base class.  */
   if (DECL_CONSTRUCTOR_P (fndecl))
     return;
 
-  bool explicit_contracts = DECL_HAS_CONTRACTS_P(fndecl);
+  bool explicit_contracts = DECL_HAS_CONTRACTS_P (fndecl);
   tree binfo = TYPE_BINFO (DECL_CONTEXT (fndecl));
   tree base_binfo;
 
@@ -2247,13 +2247,13 @@ check_override_contracts (tree fndecl)
       tree basetype = BINFO_TYPE (base_binfo);
 
       if (!TYPE_POLYMORPHIC_P (basetype))
-  	continue;
+	continue;
 
       tree basefn = look_for_overrides_here (basetype, fndecl);
       if (!basefn)
 	continue;
 
-      if (!explicit_contracts && DECL_HAS_CONTRACTS_P(basefn))
+      if (!explicit_contracts && DECL_HAS_CONTRACTS_P (basefn))
 	{
 	  /* We're inheriting basefn's contracts; create a copy of them but
 	   * replace references to their parms to our parms.  */
@@ -2263,19 +2263,18 @@ check_override_contracts (tree fndecl)
 	      /* remap post conditions */true);
 	  tree contracts = chainon (DECL_CONTRACTS (fndecl), base_contracts);
 
-	  set_decl_contracts(fndecl, contracts);
+	  set_decl_contracts (fndecl, contracts);
 
 	  if (suggest_explicit_contract)
 	    {
-	      warning_at (DECL_SOURCE_LOCATION(fndecl),
+	      warning_at (DECL_SOURCE_LOCATION (fndecl),
 			  suggest_explicit_contract,
 			  "Function implicitly inherits a contract");
-	      inform (DECL_SOURCE_LOCATION(basefn),
+	      inform (DECL_SOURCE_LOCATION (basefn),
 		      "overridden function is %qD", basefn);
 	    }
 	}
     }
-
 }
 
 /* Given a class TYPE, and a function decl FNDECL, look for

gcc/testsuite/g++.dg/contracts/cpp26/virtual_func_none.C

@@ -1,132 +1,16 @@
-// test that contracts on overriding functions are found correctly
-// { dg-do run }
-// { dg-options "-std=c++2a -fcontracts -fcontract-continuation-mode=off -fcontracts-nonattr -fcontracts-nonattr-inheritance-mode=none " }
-#include <cassert>
-
-struct contract{
-  int checked = 0;
-};
-
-
-contract a,b,c;
-
-bool checkA(){
-    a.checked++;
-    return true;
-}
-
-bool checkB(){
-    b.checked++;
-    return true;
-}
-
-bool checkC(){
-    c.checked++;
-    return true;
-}
-
-void clear_checks(){
-  a.checked = b.checked = c.checked = 0;
-
-}
+// { dg-do compile }
+// { dg-options "-std=c++2b -fcontracts -fcontracts-nonattr -fcontracts-nonattr-inheritance-mode=none " }
 
 struct Base
 {
-  virtual void f() pre (checkA()){};
-};
-
-
-struct Child0 : Base
-{
-  virtual void f() {};  //no contract
-};
+  virtual int f1() pre(true); // { dg-error "Contracts can not be added to virtual functions" }
+  virtual int f2();
 
-struct Child1 : Base
-{
-  virtual void f() pre (checkB()){};
 };
-
-
-struct GChild1 : Child0
+struct Child : Base
 {
-  virtual void f() pre (checkC()){};
-};
+  int f2() pre(true); // { dg-error "Contracts can not be added to virtual functions" }
 
-struct GChild2 : Child1
-{
-  virtual void f() {};
 };
 
 
-void fooBase(Base* b)
-{
-    b->f();
-}
-
-int main(int, char**)
-{
-  Base b0;
-  Child0 c0;
-  Child1 c1;
-  GChild1 g1;
-  GChild2 g2;
-
-
-  clear_checks();
-  fooBase(&b0);
-  assert(a.checked > 0);
-
-  clear_checks();
-  fooBase(&c0);
-  assert(a.checked == 0);
-
-  clear_checks();
-  fooBase(&c1);
-  assert(a.checked == 0);
-  assert(b.checked > 0);
-
-
-  clear_checks();
-  fooBase(&g1);
-  assert(a.checked == 0);
-  assert(b.checked == 0);
-  assert(c.checked > 0);
-
-
-  clear_checks();
-  fooBase(&g2);
-  assert(a.checked == 0);
-  assert(b.checked == 0);
-  assert(c.checked == 0);
-
-  clear_checks();
-  b0.f();
-  assert(a.checked > 0);
-
-  clear_checks();
-  c0.f();
-  assert(a.checked == 0);
-
-  clear_checks();
-  c1.f();
-  assert(a.checked == 0);
-  assert(b.checked > 0);
-
-
-  clear_checks();
-  g1.f();;
-  assert(a.checked == 0);
-  assert(b.checked == 0);
-  assert(c.checked > 0);
-
-
-  clear_checks();
-  g2.f();
-  assert(a.checked == 0);
-  assert(b.checked == 0);
-  assert(c.checked == 0);
-
-  return 0;
-}
-
-