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

diff --git a/src/semantize/typing.nit b/src/semantize/typing.nit
index bec49a8..dd98336 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`.
@@ -600,6 +600,29 @@ private class TypeVisitor
 		flow.set_var(self, variable, mtype)
 	end
 
+	# Find the exact representable most specific common super-type in `col`.
+	#
+	# Try to find the most specific common type that is a super-type of each types
+	# in `col`.
+	# In most cases, the result is simply the most general type in `col`.
+	# If nullables types are involved, then the nullable information is correctly preserved.
+	# If incomparable super-types exists in `col`, them no solution is given and the `null`
+	# value is returned (since union types are non representable in Nit)
+	#
+	# The `null` values in `col` are ignored, nulltypes (MNullType) are considered.
+	#
+	# Returns the `null` value if:
+	#
+	# * `col` is empty
+	# * `col` only have null values
+	# * there is a conflict
+	#
+	# Example (with a diamond A,B,C,D):
+	#
+	# * merge(A,B,C) -> A, because A is the most general type in {A,B,C}
+	# * merge(C,B) -> null, there is conflict, because `B or C` cannot be represented
+	# * merge(A,nullable B) -> nullable A, because A is the most general type and
+	#   the nullable information is preserved
 	fun merge_types(node: ANode, col: Array[nullable MType]): nullable MType
 	do
 		if col.length == 1 then return col.first
@@ -677,6 +700,11 @@ 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 +908,19 @@ 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 +1521,14 @@ 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)
@@ -1684,6 +1725,16 @@ 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
@@ -1849,6 +1900,15 @@ 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
@@ -2099,6 +2159,19 @@ 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
 
 ####
@@ -2179,6 +2252,15 @@ 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
 
 ####
@@ -2219,6 +2301,16 @@ 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