re PR c++/84588 (internal compiler error: Segmentation fault (contains_struct_check()))

/cp
2018-05-21  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/84588
	* parser.c (cp_parser_maybe_commit_to_declaration,
	cp_parser_check_condition_declarator): New.
	(cp_parser_simple_declaration): Use the first above.
	(cp_parser_condition): Use both the above; enforce
	[stmt.stmt]/2 about the declarator not specifying
	a function or an array; improve error-recovery.

/testsuite
2018-05-21  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/84588
	* g++.dg/cpp0x/cond1.C: New.
	* g++.dg/cpp1y/pr84588-1.C: Likewise.
	* g++.dg/cpp1y/pr84588-2.C: Likewise.
	* g++.dg/cpp1y/pr84588-3.C: Likewise.
	* g++.dg/parse/cond6.C: Likewise.
	* g++.dg/parse/cond7.C: Likewise.
	* g++.dg/parse/cond8.C: Likewise.
	* g++.dg/cpp1z/decomp16.C: Update.
	* g++.old-deja/g++.jason/cond.C: Likewise.

From-SVN: r260482

gcc/cp/ChangeLog

+2018-05-21  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/84588
+	* parser.c (cp_parser_maybe_commit_to_declaration,
+	cp_parser_check_condition_declarator): New.
+	(cp_parser_simple_declaration): Use the first above.
+	(cp_parser_condition): Use both the above; enforce
+	[stmt.stmt]/2 about the declarator not specifying
+	a function or an array; improve error-recovery.
+
 2018-05-20  Jason Merrill  <jason@redhat.com>
 
 	PR libstdc++/85843 - warning in logic_error copy constructor.

gcc/cp/parser.c

@@ -11527,6 +11527,49 @@ cp_parser_selection_statement (cp_parser* parser, bool *if_p,
     }
 }
 
+/* Helper function for cp_parser_condition and cp_parser_simple_declaration.
+   If we have seen at least one decl-specifier, and the next token
+   is not a parenthesis, then we must be looking at a declaration.
+   (After "int (" we might be looking at a functional cast.)  */
+
+static void
+cp_parser_maybe_commit_to_declaration (cp_parser* parser,
+				       bool any_specifiers_p)
+{
+  if (any_specifiers_p
+      && cp_lexer_next_token_is_not (parser->lexer, CPP_OPEN_PAREN)
+      && cp_lexer_next_token_is_not (parser->lexer, CPP_OPEN_BRACE)
+      && !cp_parser_error_occurred (parser))
+    cp_parser_commit_to_tentative_parse (parser);
+}
+
+/* Helper function for cp_parser_condition.  Enforces [stmt.stmt]/2:
+   The declarator shall not specify a function or an array.  Returns
+   TRUE if the declarator is valid, FALSE otherwise.  */
+
+static bool
+cp_parser_check_condition_declarator (cp_parser* parser,
+                                     cp_declarator *declarator,
+                                     location_t loc)
+{
+  if (function_declarator_p (declarator)
+      || declarator->kind == cdk_array)
+    {
+      if (declarator->kind == cdk_array)
+       error_at (loc, "condition declares an array");
+      else
+       error_at (loc, "condition declares a function");
+      if (parser->fully_implicit_function_template_p)
+       abort_fully_implicit_template (parser);
+      cp_parser_skip_to_closing_parenthesis (parser, /*recovering=*/true,
+                                            /*or_comma=*/false,
+                                            /*consume_paren=*/false);
+      return false;
+    }
+  else
+    return true;
+}
+
 /* Parse a condition.
 
    condition:
@@ -11563,6 +11606,10 @@ cp_parser_condition (cp_parser* parser)
 				&declares_class_or_enum);
   /* Restore the saved message.  */
   parser->type_definition_forbidden_message = saved_message;
+
+  cp_parser_maybe_commit_to_declaration (parser,
+					 type_specifiers.any_specifiers_p);
+
   /* If all is well, we might be looking at a declaration.  */
   if (!cp_parser_error_occurred (parser))
     {
@@ -11571,6 +11618,7 @@ cp_parser_condition (cp_parser* parser)
       tree attributes;
       cp_declarator *declarator;
       tree initializer = NULL_TREE;
+      location_t loc = cp_lexer_peek_token (parser->lexer)->location;
 
       /* Parse the declarator.  */
       declarator = cp_parser_declarator (parser, CP_PARSER_DECLARATOR_NAMED,
@@ -11601,6 +11649,9 @@ cp_parser_condition (cp_parser* parser)
 	  bool non_constant_p;
 	  int flags = LOOKUP_ONLYCONVERTING;
 
+	  if (!cp_parser_check_condition_declarator (parser, declarator, loc))
+	    return error_mark_node;
+
 	  /* Create the declaration.  */
 	  decl = start_decl (declarator, &type_specifiers,
 			     /*initialized_p=*/true,
@@ -11614,11 +11665,17 @@ cp_parser_condition (cp_parser* parser)
 	      CONSTRUCTOR_IS_DIRECT_INIT (initializer) = 1;
 	      flags = 0;
 	    }
-	  else
+	  else if (cp_lexer_next_token_is (parser->lexer, CPP_EQ))
 	    {
 	      /* Consume the `='.  */
-	      cp_parser_require (parser, CPP_EQ, RT_EQ);
-	      initializer = cp_parser_initializer_clause (parser, &non_constant_p);
+	      cp_lexer_consume_token (parser->lexer);
+	      initializer = cp_parser_initializer_clause (parser,
+							  &non_constant_p);
+	    }
+	  else
+	    {
+	      cp_parser_error (parser, "expected initializer");
+	      initializer = error_mark_node;
 	    }
 	  if (BRACE_ENCLOSED_INITIALIZER_P (initializer))
 	    maybe_warn_cpp0x (CPP0X_INITIALIZER_LISTS);
@@ -12936,14 +12993,8 @@ cp_parser_simple_declaration (cp_parser* parser,
       goto done;
     }
 
-  /* If we have seen at least one decl-specifier, and the next token
-     is not a parenthesis, then we must be looking at a declaration.
-     (After "int (" we might be looking at a functional cast.)  */
-  if (decl_specifiers.any_specifiers_p
-      && cp_lexer_next_token_is_not (parser->lexer, CPP_OPEN_PAREN)
-      && cp_lexer_next_token_is_not (parser->lexer, CPP_OPEN_BRACE)
-      && !cp_parser_error_occurred (parser))
-    cp_parser_commit_to_tentative_parse (parser);
+  cp_parser_maybe_commit_to_declaration (parser,
+					 decl_specifiers.any_specifiers_p);
 
   /* Look for C++17 decomposition declaration.  */
   for (size_t n = 1; ; n++)

gcc/testsuite/ChangeLog

+2018-05-21  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/84588
+	* g++.dg/cpp0x/cond1.C: New.
+	* g++.dg/cpp1y/pr84588-1.C: Likewise.
+	* g++.dg/cpp1y/pr84588-2.C: Likewise.
+	* g++.dg/cpp1y/pr84588-3.C: Likewise.
+	* g++.dg/parse/cond6.C: Likewise.
+	* g++.dg/parse/cond7.C: Likewise.
+	* g++.dg/parse/cond8.C: Likewise.
+	* g++.dg/cpp1z/decomp16.C: Update.
+	* g++.old-deja/g++.jason/cond.C: Likewise.
+
 2018-05-21  Steven G. Kargl  <kargl@gcc.gnu.org>
 
 	ChangeLog for r260480

gcc/testsuite/g++.dg/cpp0x/cond1.C

+// PR c++/84588
+// { dg-do compile { target c++11 } }
+
+void foo()
+{
+  if (int bar() {});  // { dg-error "condition declares a function" }
+
+  for (;int bar() {};);  // { dg-error "condition declares a function" }
+
+  while (int bar() {});  // { dg-error "condition declares a function" }
+
+  if (int a[] {});  // { dg-error "condition declares an array" }
+
+  for (;int a[] {};);  // { dg-error "condition declares an array" }
+
+  while (int a[] {});  // { dg-error "condition declares an array" }
+}

gcc/testsuite/g++.dg/cpp1y/pr84588-1.C

+// { dg-do compile { target c++14 } }
+
+struct a {
+  void b() {}
+  void c(void (*) () = [] {
+      if (a a(int auto) {})  // { dg-error "two or more data types|condition declares a function" }
+      ;
+  }) {}
+};
+
+struct d {
+  void e() {}
+  void f(void (*) () = [] {
+      for (;d d(int auto) {};)  // { dg-error "two or more data types|condition declares a function" }
+      ;
+  }) {}
+};
+
+struct g {
+  void h() {}
+  void i(void (*) () = [] {
+      while (g g(int auto) {})  // { dg-error "two or more data types|condition declares a function" }
+      ;
+  }) {}
+};

gcc/testsuite/g++.dg/cpp1y/pr84588-2.C

+// { dg-do compile { target c++14 } }
+
+struct a {
+  void b() {}
+  void c(void (*) () = [] {
+      if (a a(int auto))  // { dg-error "two or more data types|condition declares a function" }
+      ;
+  }) {}
+};
+
+struct d {
+  void e() {}
+  void f(void (*) () = [] {
+      for (;d d(int auto);)  // { dg-error "two or more data types|condition declares a function" }
+      ;
+  }) {}
+};
+
+struct g {
+  void h() {}
+  void i(void (*) () = [] {
+      while (g g(int auto))  // { dg-error "two or more data types|condition declares a function" }
+      ;
+  }) {}
+};

gcc/testsuite/g++.dg/cpp1y/pr84588-3.C

+// { dg-do compile { target c++14 } }
+
+struct a {
+  void b() {}
+  void c(void (*) () = [] {
+      if (a a(int auto)JUNK)  // { dg-error "two or more data types|condition declares a function" }
+      ;
+  }) {}
+};
+
+struct d {
+  void e() {}
+  void f(void (*) () = [] {
+      for (;d d(int auto)JUNK;)  // { dg-error "two or more data types|condition declares a function" }
+      ;
+  }) {}
+};
+
+struct g {
+  void h() {}
+  void i(void (*) () = [] {
+      while (g g(int auto)JUNK)  // { dg-error "two or more data types|condition declares a function" }
+      ;
+  }) {}
+};

gcc/testsuite/g++.dg/cpp1z/decomp16.C

@@ -8,7 +8,7 @@ void
 foo ()
 {
   auto [ a, b ] = A ();
-  for (; auto [ a, b ] = A (); )			// { dg-error "expected" }
+  for (; auto [ a, b ] = A (); )			// { dg-error "expected|no match" }
     ;
   for (; false; auto [ a, b ] = A ())			// { dg-error "expected" }
     ;

gcc/testsuite/g++.dg/parse/cond6.C

+// PR c++/84588
+
+void foo()
+{
+  if (int bar());  // { dg-error "condition declares a function" }
+
+  for (;int bar(););  // { dg-error "condition declares a function" }
+
+  while (int bar());  // { dg-error "condition declares a function" }
+
+  if (int a[]);  // { dg-error "condition declares an array" }
+
+  for (;int a[];);  // { dg-error "condition declares an array" }
+
+  while (int a[]);  // { dg-error "condition declares an array" }
+}

gcc/testsuite/g++.dg/parse/cond7.C

+// PR c++/84588
+
+bool (foo()) { return 0; } // declaration
+
+void bar()
+{
+  if (bool (foo())); // expression
+
+  for (;bool (foo());); // expression
+
+  while (bool (foo())); // expression
+}

gcc/testsuite/g++.dg/parse/cond8.C

+// PR c++/84588
+
+void foo()
+{
+  if (int x);  // { dg-error "expected initializer" }
+
+  for (;int x;);  // { dg-error "expected initializer" }
+
+  while (int x);  // { dg-error "expected initializer" }
+}

gcc/testsuite/g++.old-deja/g++.jason/cond.C

@@ -47,11 +47,10 @@ int main()
   if (struct B * foo = new B)
     ;
 
-  if (int f () = 1)		// { dg-warning "extern" "extern" } 
-  // { dg-error "is initialized like a variable" "var" { target *-*-* } .-1 }
+  if (int f () = 1)		// { dg-error "declares a function" } 
     ;
   
-  if (int a[2] = {1, 2})	// { dg-error "extended init" "" { target { ! c++11 } } }
+  if (int a[2] = {1, 2})	// { dg-error "declares an array" }
     ;
 
 }