refinements in string interpolation

* compile.c (iseq_compile_each0): insert to_s method call, so that
  refinements activated at the caller should take place.
  [Feature #13812]

* insns.def (tostring): fix up converted object to a string,
  infect and fallback.

* insns.def (branchiftype): new instruction for conversion.
  branches if TOS is an instance of the given type.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@59950 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

NEWS

@@ -18,6 +18,8 @@ with all sufficient information, see the ChangeLog file or Redmine
 
 * rescue/else/ensure are allowed inside do/end blocks.  [Feature #12906]
 
+* refinements take place in string interpolations.  [Feature #13812]
+
 === Core classes updates (outstanding ones only)
 
 * Array

compile.c

@@ -6180,7 +6180,15 @@ iseq_compile_each0(rb_iseq_t *iseq, LINK_ANCHOR *const ret, NODE *node, int popp
 	    ADD_INSN(ret, line, pop);
 	}
 	else {
+	    const unsigned int flag = VM_CALL_FCALL;
+	    LABEL *isstr = NEW_LABEL(line);
+	    ADD_INSN(ret, line, dup);
+	    ADD_INSN2(ret, line, branchiftype, INT2FIX(T_STRING), isstr);
+	    LABEL_REF(isstr);
+	    ADD_INSN(ret, line, dup);
+	    ADD_SEND_R(ret, line, idTo_s, INT2FIX(0), NULL, INT2FIX(flag), NULL);
 	    ADD_INSN(ret, line, tostring);
+	    ADD_LABEL(ret, isstr);
 	}
 	break;
       }

insns.def

@@ -356,10 +356,11 @@ concatstrings
 DEFINE_INSN
 tostring
 ()
-(VALUE val)
+(VALUE val, VALUE str)
 (VALUE val)
 {
-    val = rb_obj_as_string(val);
+    VALUE rb_obj_as_string_result(VALUE str, VALUE obj);
+    val = rb_obj_as_string_result(str, val);
 }
 
 /**
@@ -1038,6 +1039,23 @@ branchnil
     }
 }
 
+/**
+  @c jump
+  @e if val is type, set PC to (PC + dst).
+  @j もし val が type ならば、PC を (PC + dst) にする。
+ */
+DEFINE_INSN
+branchiftype
+(rb_num_t type, OFFSET dst)
+(VALUE val)
+()
+{
+    if (TYPE(val) == (int)type) {
+	RUBY_VM_CHECK_INTS(th);
+	JUMP(dst);
+    }
+}
+
 
 /**********************************************************/
 /* for optimize                                           */

string.c

@@ -1404,6 +1404,8 @@ str_shared_replace(VALUE str, VALUE str2)
     }
 }
 
+VALUE rb_obj_as_string_result(VALUE str, VALUE obj);
+
 VALUE
 rb_obj_as_string(VALUE obj)
 {
@@ -1413,6 +1415,12 @@ rb_obj_as_string(VALUE obj)
 	return obj;
     }
     str = rb_funcall(obj, idTo_s, 0);
+    return rb_obj_as_string_result(str, obj);
+}
+
+VALUE
+rb_obj_as_string_result(VALUE str, VALUE obj)
+{
     if (!RB_TYPE_P(str, T_STRING))
 	return rb_any_to_s(obj);
     if (!FL_TEST_RAW(str, RSTRING_FSTR) && FL_ABLE(obj))

test/ruby/test_refinement.rb

@@ -1961,6 +1961,19 @@ class TestRefinement < Test::Unit::TestCase
     end
   end
 
+  class ToString
+    c = self
+    using Module.new {refine(c) {def to_s; "ok"; end}}
+    def string
+      "#{self}"
+    end
+  end
+
+  def test_tostring
+    assert_equal("ok", ToString.new.string)
+    assert_predicate(ToString.new.taint.string, :tainted?)
+  end
+
   private
 
   def eval_using(mod, s)