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

diff --git a/src/semantize/typing.nit b/src/semantize/typing.nit
index 932256f..6a6d943 100644
--- a/src/semantize/typing.nit
+++ b/src/semantize/typing.nit
@@ -266,8 +266,13 @@ private class TypeVisitor
 
 		#debug("recv: {recvtype} (aka {unsafe_type})")
 		if recvtype isa MNullType then
-			self.error(node, "Error: Method '{name}' call on 'null'.")
-			return null
+			# `null` only accepts some methods of object.
+			if name == "==" or name == "!=" or name == "is_same_instance" then
+				unsafe_type = mmodule.object_type.as_nullable
+			else
+				self.error(node, "Error: Method '{name}' call on 'null'.")
+				return null
+			end
 		end
 
 		var mproperty = self.try_get_mproperty_by_name2(node, unsafe_type, name)
@@ -592,6 +597,8 @@ end
 redef class AAttrPropdef
 	redef fun do_typing(modelbuilder: ModelBuilder)
 	do
+		if not has_value then return
+
 		var mpropdef = self.mpropdef.as(not null)
 		var v = new TypeVisitor(modelbuilder, mpropdef.mclassdef.mmodule, mpropdef)
 		self.selfvariable = v.selfvariable
@@ -604,6 +611,10 @@ redef class AAttrPropdef
 		var nblock = self.n_block
 		if nblock != null then
 			v.visit_stmt(nblock)
+			if not nblock.after_flow_context.is_unreachable then
+				# We reach the end of the init without having a return, it is bad
+				v.error(self, "Control error: Reached end of block (a 'return' with a value was expected).")
+			end
 		end
 	end
 end
@@ -970,7 +981,7 @@ redef class AForExpr
 			is_col = true
 		end
 
-		if mapit_cla != null and v.is_subtype(ittype, mapit_cla.get_mtype([objcla.mclass_type, objcla.mclass_type.as_nullable])) then
+		if mapit_cla != null and v.is_subtype(ittype, mapit_cla.get_mtype([objcla.mclass_type.as_nullable, objcla.mclass_type.as_nullable])) then
 			# Map Iterator
 			var coltype = ittype.supertype_to(v.mmodule, v.anchor, mapit_cla)
 			var variables = self.variables
@@ -1238,7 +1249,7 @@ redef class AArrayExpr
 		if mtype == null then
 			mtype = v.merge_types(self, mtypes)
 		end
-		if mtype == null then
+		if mtype == null or mtype isa MNullType then
 			v.error(self, "Type Error: ambiguous array type {mtypes.join(" ")}")
 			return
 		end