X-Git-Url: http://nitlanguage.org

diff --git a/src/compiler/separate_compiler.nit b/src/compiler/separate_compiler.nit
index 8152658..1f1cf67 100644
--- a/src/compiler/separate_compiler.nit
+++ b/src/compiler/separate_compiler.nit
@@ -1126,10 +1126,10 @@ class SeparateCompilerVisitor
 		var res: nullable RuntimeVariable = null
 		var recv = arguments.first
 		var consider_null = not self.compiler.modelbuilder.toolcontext.opt_no_check_null.value or mmethod.name == "==" or mmethod.name == "!="
-		var maybenull = recv.mcasttype isa MNullableType and consider_null
+		var maybenull = (recv.mcasttype isa MNullableType or recv.mcasttype isa MNullType) and consider_null
 		if maybenull then
 			self.add("if ({recv} == NULL) \{")
-			if mmethod.name == "==" then
+			if mmethod.name == "==" or mmethod.name == "is_same_instance" then
 				res = self.new_var(bool_type)
 				var arg = arguments[1]
 				if arg.mcasttype isa MNullableType then
@@ -1156,15 +1156,15 @@ class SeparateCompilerVisitor
 		else
 			self.add("\{")
 		end
-		if not self.compiler.modelbuilder.toolcontext.opt_no_shortcut_equate.value and (mmethod.name == "==" or mmethod.name == "!=") then
-			if res == null then res = self.new_var(bool_type)
-			# Recv is not null, thus is arg is, it is easy to conclude (and respect the invariants)
+		if not self.compiler.modelbuilder.toolcontext.opt_no_shortcut_equate.value and (mmethod.name == "==" or mmethod.name == "!=" or mmethod.name == "is_same_instance") then
+			# Recv is not null, thus if arg is, it is easy to conclude (and respect the invariants)
 			var arg = arguments[1]
 			if arg.mcasttype isa MNullType then
-				if mmethod.name == "==" then
-					self.add("{res} = 0; /* arg is null but recv is not */")
-				else
+				if res == null then res = self.new_var(bool_type)
+				if mmethod.name == "!=" then
 					self.add("{res} = 1; /* arg is null and recv is not */")
+				else # `==` and `is_same_instance`
+					self.add("{res} = 0; /* arg is null but recv is not */")
 				end
 				self.add("\}") # closes the null case
 				self.add("if (0) \{") # what follow is useless, CC will drop it
@@ -1248,7 +1248,7 @@ class SeparateCompilerVisitor
 			(compiler.modelbuilder.toolcontext.opt_inline_some_methods.value and mmethoddef.can_inline(self)) then
 			compiler.modelbuilder.nb_invok_by_inline += 1
 			if compiler.modelbuilder.toolcontext.opt_invocation_metrics.value then add("count_invoke_by_inline++;")
-			var frame = new Frame(self, mmethoddef, recvtype, arguments)
+			var frame = new StaticFrame(self, mmethoddef, recvtype, arguments)
 			frame.returnlabel = self.get_name("RET_LABEL")
 			frame.returnvar = res
 			var old_frame = self.frame
@@ -1298,11 +1298,11 @@ class SeparateCompilerVisitor
 		# of the method (ie recv) if the static type is unresolved
 		# This is more complex than usual because the unresolved type must not be resolved
 		# with the current receiver (ie self).
-		# Therefore to isolate the resolution from self, a local Frame is created.
+		# Therefore to isolate the resolution from self, a local StaticFrame is created.
 		# One can see this implementation as an inlined method of the receiver whose only
 		# job is to allocate the array
 		var old_frame = self.frame
-		var frame = new Frame(self, mpropdef, mpropdef.mclassdef.bound_mtype, [recv])
+		var frame = new StaticFrame(self, mpropdef, mpropdef.mclassdef.bound_mtype, [recv])
 		self.frame = frame
 		#print "required Array[{elttype}] for recv {recv.inspect}. bound=Array[{self.resolve_for(elttype, recv)}]. selfvar={frame.arguments.first.inspect}"
 		var res = self.array_instance(varargs, elttype)
@@ -1820,7 +1820,7 @@ class SeparateRuntimeFunction
 		var v = compiler.new_visitor
 		var selfvar = new RuntimeVariable("self", recv, recv)
 		var arguments = new Array[RuntimeVariable]
-		var frame = new Frame(v, mmethoddef, recv, arguments)
+		var frame = new StaticFrame(v, mmethoddef, recv, arguments)
 		v.frame = frame
 
 		var msignature = mmethoddef.msignature.resolve_for(mmethoddef.mclassdef.bound_mtype, mmethoddef.mclassdef.bound_mtype, mmethoddef.mclassdef.mmodule, true)
@@ -1892,7 +1892,7 @@ class VirtualRuntimeFunction
 		var v = compiler.new_visitor
 		var selfvar = new RuntimeVariable("self", v.object_type, recv)
 		var arguments = new Array[RuntimeVariable]
-		var frame = new Frame(v, mmethoddef, recv, arguments)
+		var frame = new StaticFrame(v, mmethoddef, recv, arguments)
 		v.frame = frame
 
 		var sig = new FlatBuffer