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

diff --git a/src/semantize/typing.nit b/src/semantize/typing.nit
index 1dfaec6..343edbd 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)
@@ -604,6 +609,10 @@ 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
@@ -756,11 +765,6 @@ redef class AReassignFormExpr
 
 		self.read_type = readtype
 
-		if readtype isa MNullType then
-			v.error(self, "Error: Method '{reassign_name}' call on 'null'.")
-			return null
-		end
-
 		var callsite = v.get_method(self, readtype, reassign_name, false)
 		if callsite == null then return null # Skip error
 		self.reassign_callsite = callsite
@@ -975,7 +979,7 @@ 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
@@ -1243,7 +1247,7 @@ 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
@@ -1407,10 +1411,6 @@ redef class ASendExpr
 		var name = self.property_name
 
 		if recvtype == null then return # Forward error
-		if recvtype isa MNullType then
-			v.error(self, "Error: Method '{name}' call on 'null'.")
-			return
-		end
 
 		var callsite = v.get_method(self, recvtype, name, self.n_expr isa ASelfExpr)
 		if callsite == null then return
@@ -1554,10 +1554,6 @@ redef class ASendReassignFormExpr
 		var name = self.property_name
 
 		if recvtype == null then return # Forward error
-		if recvtype isa MNullType then
-			v.error(self, "Error: Method '{name}' call on 'null'.")
-			return
-		end
 
 		var for_self = self.n_expr isa ASelfExpr
 		var callsite = v.get_method(self, recvtype, name, for_self)