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

diff --git a/src/semantize/typing.nit b/src/semantize/typing.nit
index 6c4de01..50ba70e 100644
--- a/src/semantize/typing.nit
+++ b/src/semantize/typing.nit
@@ -102,9 +102,9 @@ private class TypeVisitor
 	end
 
 	# Check that `sub` is a subtype of `sup`.
-	# If `sub` is not a valid suptype, then display an error on `node` an return null.
-	# If `sub` is a safe subtype of `sup` then return `sub`.
-	# If `sub` is an unsafe subtype (ie an implicit cast is required), then return `sup`.
+	# If `sub` is not a valid suptype, then display an error on `node` and return `null`.
+	# If `sub` is a safe subtype of `sup`, then return `sub`.
+	# If `sub` is an unsafe subtype (i.e., an implicit cast is required), then return `sup`.
 	#
 	# The point of the return type is to determinate the usable type on an expression when `autocast` is true:
 	# If the suptype is safe, then the return type is the one on the expression typed by `sub`.
@@ -117,7 +117,7 @@ private class TypeVisitor
 			#node.debug("Unsafe typing: expected {sup}, got {sub}")
 			return sup
 		end
-		if sup isa MBottomType then return null # Skip error
+		if sup isa MErrorType then return null # Skip error
 		if sub.need_anchor then
 			var u = anchor_to(sub)
 			self.modelbuilder.error(node, "Type Error: expected `{sup}`, got `{sub}: {u}`.")
@@ -677,6 +677,11 @@ class CallSite
 		if map == null then is_broken = true
 		return map == null
 	end
+
+	# Information about the callsite to display on a node
+	fun dump_info(v: ASTDump): String do
+		return "{recv}.{mpropdef}{msignature}"
+	end
 end
 
 redef class Variable
@@ -880,6 +885,19 @@ redef class AExpr
 	#
 	# This attribute is meaning less on expressions not used as attributes.
 	var vararg_decl: Int = 0
+
+	redef fun dump_info(v) do
+		var res = super
+		var mtype = self.mtype
+		if mtype != null then
+			res += v.yellow(":{mtype}")
+		end
+		var ict = self.implicit_cast_to
+		if ict != null then
+			res += v.yellow("(.as({ict}))")
+		end
+		return res
+	end
 end
 
 redef class ABlockExpr
@@ -1480,14 +1498,14 @@ redef class AugmentedStringFormExpr
 	var newline: nullable CallSite = null
 	# Regex::extended, used for suffix `b` on `re`
 	var extended: nullable CallSite = null
-	# NativeString::to_bytes_with_copy, used for prefix `b`
+	# CString::to_bytes_with_copy, used for prefix `b`
 	var to_bytes_with_copy: nullable CallSite = null
 
 	redef fun accept_typing(v) do
 		var mclass = v.get_mclass(self, "String")
 		if mclass == null then return # Forward error
 		if is_bytestring then
-			to_bytes_with_copy = v.get_method(self, v.mmodule.native_string_type, "to_bytes_with_copy", false)
+			to_bytes_with_copy = v.get_method(self, v.mmodule.c_string_type, "to_bytes_with_copy", false)
 			mclass = v.get_mclass(self, "Bytes")
 		else if is_re then
 			to_re = v.get_method(self, mclass.mclass_type, "to_re", false)
@@ -1666,11 +1684,15 @@ redef class AIsaExpr
 
 		var variable = self.n_expr.its_variable
 		if variable != null then
-			#var orig = self.n_expr.mtype
+			var orig = self.n_expr.mtype
 			#var from = if orig != null then orig.to_s else "invalid"
 			#var to = if mtype != null then mtype.to_s else "invalid"
 			#debug("adapt {variable}: {from} -> {to}")
-			self.after_flow_context.when_true.set_var(v, variable, mtype)
+
+			# Do not adapt if there is no information gain (i.e. adapt to a supertype)
+			if mtype == null or orig == null or not v.is_subtype(orig, mtype) then
+				self.after_flow_context.when_true.set_var(v, variable, mtype)
+			end
 		end
 
 		self.mtype = v.type_bool(self)
@@ -1680,6 +1702,16 @@ redef class AIsaExpr
 	do
 		v.check_expr_cast(self, self.n_expr, self.n_type)
 	end
+
+	redef fun dump_info(v) do
+		var res = super
+		var mtype = self.cast_type
+		if mtype != null then
+			res += v.yellow(".as({mtype})")
+		end
+		return res
+	end
+
 end
 
 redef class AAsCastExpr
@@ -1845,6 +1877,15 @@ redef class ASendExpr
 	fun raw_arguments: Array[AExpr] do return compute_raw_arguments
 
 	private fun compute_raw_arguments: Array[AExpr] is abstract
+
+	redef fun dump_info(v) do
+		var res = super
+		var callsite = self.callsite
+		if callsite != null then
+			res += v.yellow(" call="+callsite.dump_info(v))
+		end
+		return res
+	end
 end
 
 redef class ABinopExpr
@@ -2095,6 +2136,19 @@ redef class ASuperExpr
 
 		self.is_typed = true
 	end
+
+	redef fun dump_info(v) do
+		var res = super
+		var callsite = self.callsite
+		if callsite != null then
+			res += v.yellow(" super-init="+callsite.dump_info(v))
+		end
+		var mpropdef = self.mpropdef
+		if mpropdef != null then
+			res += v.yellow(" call-next-method="+mpropdef.to_s)
+		end
+		return res
+	end
 end
 
 ####
@@ -2175,6 +2229,15 @@ redef class ANewExpr
 		var args = n_args.to_a
 		callsite.check_signature(v, node, args)
 	end
+
+	redef fun dump_info(v) do
+		var res = super
+		var callsite = self.callsite
+		if callsite != null then
+			res += v.yellow(" call="+callsite.dump_info(v))
+		end
+		return res
+	end
 end
 
 ####
@@ -2215,6 +2278,16 @@ redef class AAttrFormExpr
 		attr_type = v.resolve_for(attr_type, recvtype, self.n_expr isa ASelfExpr)
 		self.attr_type = attr_type
 	end
+
+	redef fun dump_info(v) do
+		var res = super
+		var mproperty = self.mproperty
+		var attr_type = self.attr_type
+		if mproperty != null then
+			res += v.yellow(" attr={mproperty}:{attr_type or else "BROKEN"}")
+		end
+		return res
+	end
 end
 
 redef class AAttrExpr