require unsafe for dereferencing

vlib/compiler/fn.v

@@ -1441,7 +1441,9 @@ fn (p mut Parser) dispatch_generic_fn_instance(f mut Fn, ti TypeInst) {
 	p.cgen.tmp_line = ''
 	p.cgen.cur_line = ''
 	p.cgen.lines = []string
+	unsafe { // TODO
 		p.cur_fn = *f
+	}
 	for arg in f.args {
 		p.register_var(arg)
 	}

vlib/compiler/parser.v

@@ -1481,6 +1481,10 @@ fn (p mut Parser) get_var_type(name string, is_ptr bool, is_deref bool) string {
 	mut typ := p.var_expr(v)
 	// *var
 	if is_deref {
+		if !p.inside_unsafe {
+			p.warn('dereferencing can only be done inside an `unsafe` block')
+		}	
+		
 		if !typ.contains('*') && !typ.ends_with('ptr') {
 			println('name="$name", t=$v.typ')
 			p.error('dereferencing requires a pointer, but got `$typ`')

vlib/rand/rand.v

@@ -22,8 +22,10 @@ fn C.rand() int
  * @return a value between 0 and C.RAND_MAX (inclusive)
  */
 pub fn rand_r(seed &int) int {
+	unsafe {
 	mut rs := seed
 	ns := ( *rs * 1103515245 + 12345 )
 	*rs = ns
 	return ns & 0x7fffffff
+	}
 }