compiler: Prohibit comparisons of funcs, maps, and slices to non-nil.

From-SVN: r182703

gcc/go/gofrontend/expressions.cc

@@ -6052,11 +6052,11 @@ Binary_expression::do_determine_type(const Type_context* context)
 }
 
 // Report an error if the binary operator OP does not support TYPE.
-// Return whether the operation is OK.  This should not be used for
-// shift.
+// OTYPE is the type of the other operand.  Return whether the
+// operation is OK.  This should not be used for shift.
 
 bool
-Binary_expression::check_operator_type(Operator op, Type* type,
+Binary_expression::check_operator_type(Operator op, Type* type, Type* otype,
 				       Location location)
 {
   switch (op)
@@ -6092,6 +6092,16 @@ Binary_expression::check_operator_type(Operator op, Type* type,
 		    "or function type"));
 	  return false;
 	}
+      if ((type->is_slice_type()
+	   || type->map_type() != NULL
+	   || type->function_type() != NULL)
+	  && !otype->is_nil_type())
+	{
+	  error_at(location,
+		   ("slice, map, and function types may only "
+		    "be compared to nil"));
+	  return false;
+	}
       break;
 
     case OPERATOR_LT:
@@ -6189,8 +6199,10 @@ Binary_expression::do_check_types(Gogo*)
 	  return;
 	}
       if (!Binary_expression::check_operator_type(this->op_, left_type,
+						  right_type,
 						  this->location())
 	  || !Binary_expression::check_operator_type(this->op_, right_type,
+						     left_type,
 						     this->location()))
 	{
 	  this->set_is_error();
@@ -6205,6 +6217,7 @@ Binary_expression::do_check_types(Gogo*)
 	  return;
 	}
       if (!Binary_expression::check_operator_type(this->op_, left_type,
+						  right_type,
 						  this->location()))
 	{
 	  this->set_is_error();

gcc/go/gofrontend/expressions.h

@@ -1147,9 +1147,9 @@ class Binary_expression : public Expression
   do_import(Import*);
 
   // Report an error if OP can not be applied to TYPE.  Return whether
-  // it can.
+  // it can.  OTYPE is the type of the other operand.
   static bool
-  check_operator_type(Operator op, Type* type, Location);
+  check_operator_type(Operator op, Type* type, Type* otype, Location);
 
  protected:
   int

gcc/go/gofrontend/types.cc

@@ -1235,8 +1235,6 @@ Type::type_functions(const char** hash_fn, const char** equal_fn) const
     case Type::TYPE_FLOAT:
     case Type::TYPE_COMPLEX:
     case Type::TYPE_POINTER:
-    case Type::TYPE_FUNCTION:
-    case Type::TYPE_MAP:
     case Type::TYPE_CHANNEL:
       *hash_fn = "__go_type_hash_identity";
       *equal_fn = "__go_type_equal_identity";
@@ -1249,6 +1247,8 @@ Type::type_functions(const char** hash_fn, const char** equal_fn) const
 
     case Type::TYPE_STRUCT:
     case Type::TYPE_ARRAY:
+    case Type::TYPE_FUNCTION:
+    case Type::TYPE_MAP:
       // These types can not be hashed or compared.
       *hash_fn = "__go_type_hash_error";
       *equal_fn = "__go_type_equal_error";
@@ -4731,7 +4731,9 @@ bool
 Map_type::do_verify()
 {
   if (this->key_type_->struct_type() != NULL
-      || this->key_type_->array_type() != NULL)
+      || this->key_type_->array_type() != NULL
+      || this->key_type_->function_type() != NULL
+      || this->key_type_->map_type() != NULL)
     {
       error_at(this->location_, "invalid map key type");
       return false;

gcc/testsuite/go.test/test/closure.go

@@ -76,7 +76,6 @@ func h() {
 
 func newfunc() func(int) int { return func(x int) int { return x } }
 
-
 func main() {
 	go f()
 	check([]int{1, 4, 5, 4})
@@ -90,10 +89,6 @@ func main() {
 	check([]int{100, 200, 101, 201, 500, 101, 201, 500})
 
 	x, y := newfunc(), newfunc()
-	if x == y {
-		println("newfunc returned same func")
-		panic("fail")
-	}
 	if x(1) != 1 || y(2) != 2 {
 		println("newfunc returned broken funcs")
 		panic("fail")

gcc/testsuite/go.test/test/cmp1.go

-// $G $D/$F.go && $L $F.$A && ./$A.out
-
-// Copyright 2009 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package main
-
-import "unsafe"
-
-func use(bool) {}
-
-func stringptr(s string) uintptr { return *(*uintptr)(unsafe.Pointer(&s)) }
-
-func isfalse(b bool) {
-	if b {
-		// stack will explain where
-		panic("wanted false, got true")
-	}
-}
-
-func istrue(b bool) {
-	if !b {
-		// stack will explain where
-		panic("wanted true, got false")
-	}
-}
-
-type T *int
-
-func main() {
-	var a []int
-	var b map[string]int
-
-	var c string = "hello"
-	var d string = "hel" // try to get different pointer
-	d = d + "lo"
-	if stringptr(c) == stringptr(d) {
-		panic("compiler too smart -- got same string")
-	}
-
-	var e = make(chan int)
-
-	var ia interface{} = a
-	var ib interface{} = b
-	var ic interface{} = c
-	var id interface{} = d
-	var ie interface{} = e
-
-	// these comparisons are okay because
-	// string compare is okay and the others
-	// are comparisons where the types differ.
-	isfalse(ia == ib)
-	isfalse(ia == ic)
-	isfalse(ia == id)
-	isfalse(ib == ic)
-	isfalse(ib == id)
-	istrue(ic == id)
-	istrue(ie == ie)
-	
-	// these are okay because one side of the
-	// comparison need only be assignable to the other.
-	isfalse(a == ib)
-	isfalse(a == ic)
-	isfalse(a == id)
-	isfalse(b == ic)
-	isfalse(b == id)
-	istrue(c == id)
-	istrue(e == ie)
-
-	isfalse(ia == b)
-	isfalse(ia == c)
-	isfalse(ia == d)
-	isfalse(ib == c)
-	isfalse(ib == d)
-	istrue(ic == d)
-	istrue(ie == e)
-
-	// 6g used to let this go through as true.
-	var g uint64 = 123
-	var h int64 = 123
-	var ig interface{} = g
-	var ih interface{} = h
-	isfalse(ig == ih)
-
-	// map of interface should use == on interface values,
-	// not memory.
-	// TODO: should m[c], m[d] be valid here?
-	var m = make(map[interface{}]int)
-	m[ic] = 1
-	m[id] = 2
-	if m[ic] != 2 {
-		println("m[ic] = ", m[ic])
-		panic("bad m[ic]")
-	}
-	
-	// non-interface comparisons
-	{
-		c := make(chan int)
-		c1 := (<-chan int)(c)
-		c2 := (chan<- int)(c)
-		istrue(c == c1)
-		istrue(c == c2)
-		istrue(c1 == c)
-		istrue(c2 == c)
-		
-		d := make(chan int)
-		isfalse(c == d)
-		isfalse(d == c)
-		isfalse(d == c1)
-		isfalse(d == c2)
-		isfalse(c1 == d)
-		isfalse(c2 == d)
-	}
-
-	// named types vs not
-	{
-		var x = new(int)
-		var y T
-		var z T = x
-		
-		isfalse(x == y)
-		istrue(x == z)
-		isfalse(y == z)
-
-		isfalse(y == x)
-		istrue(z == x)
-		isfalse(z == y)
-	}
-}

gcc/testsuite/go.test/test/fixedbugs/bug285.go

@@ -45,20 +45,6 @@ func main() {
 	mp[p] = 42
 	mp[&T{7}] = 42
 
-	type F func(x int)
-	f := func(x int) {}
-	mf := make(map[F]int)
-	mf[nil] = 42
-	mf[f] = 42
-	mf[func(x int) {}] = 42
-
-	type M map[int]int
-	m := make(M)
-	mm := make(map[M]int)
-	mm[nil] = 42
-	mm[m] = 42
-	mm[make(M)] = 42
-
 	type C chan int
 	c := make(C)
 	mc := make(map[C]int)

gcc/testsuite/go.test/test/typeswitch.go

@@ -82,9 +82,9 @@ func main() {
 		case []int:
 			assert(x[3] == 3 && i == Array, "array")
 		case map[string]int:
-			assert(x == m && i == Map, "map")
+			assert(x != nil && i == Map, "map")
 		case func(i int) interface{}:
-			assert(x == f && i == Func, "fun")
+			assert(x != nil && i == Func, "fun")
 		default:
 			assert(false, "unknown")
 		}
@@ -111,5 +111,4 @@ func main() {
 	default:
 		assert(false, "switch 4 unknown")
 	}
-
 }