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

diff --git a/src/modelbuilder_base.nit b/src/modelbuilder_base.nit
index 9995338..5cc235f 100644
--- a/src/modelbuilder_base.nit
+++ b/src/modelbuilder_base.nit
@@ -74,13 +74,53 @@ class ModelBuilder
 			if res == null then
 				res = mclass
 			else
-				error(anode, "Ambigous class name '{name}'; conflict between {mclass.full_name} and {res.full_name}")
+				error(anode, "Error: ambiguous class name `{name}`; conflict between `{mclass.full_name}` and `{res.full_name}`.")
 				return null
 			end
 		end
 		return res
 	end
 
+	# Return a class identified by `qid` visible by the module `mmodule`.
+	# Visibility in modules and qualified names are correctly handled.
+	#
+	# If more than one class exists, then null is silently returned.
+	# It is up to the caller to post-analysis the result and display a correct error message.
+	# The method `class_not_found` can be used to display such a message.
+	fun try_get_mclass_by_qid(qid: AQclassid, mmodule: MModule): nullable MClass
+	do
+		var name = qid.n_id.text
+
+		var classes = model.get_mclasses_by_name(name)
+		if classes == null then
+			return null
+		end
+
+		var res: nullable MClass = null
+		for mclass in classes do
+			if not mmodule.in_importation <= mclass.intro_mmodule then continue
+			if not mmodule.is_visible(mclass.intro_mmodule, mclass.visibility) then continue
+			if not qid.accept(mclass) then continue
+			if res == null then
+				res = mclass
+			else
+				return null
+			end
+		end
+
+		return res
+	end
+
+	# Like `try_get_mclass_by_name` but display an error message when the class is not found
+	fun get_mclass_by_name(node: ANode, mmodule: MModule, name: String): nullable MClass
+	do
+		var mclass = try_get_mclass_by_name(node, mmodule, name)
+		if mclass == null then
+			error(node, "Type Error: missing primitive class `{name}'.")
+		end
+		return mclass
+	end
+
 	# Return a property named `name` on the type `mtype` visible in the module `mmodule`.
 	# Visibility in modules is correctly handled.
 	# Protected properties are returned (it is up to the caller to check and reject protected properties).
@@ -158,7 +198,7 @@ class ModelBuilder
 			assert ress.length > 1
 			var s = new Array[String]
 			for mprop in ress do s.add mprop.full_name
-			self.error(anode, "Ambigous property name '{name}' for {mtype}; conflict between {s.join(" and ")}")
+			self.error(anode, "Error: ambiguous property name `{name}` for `{mtype}`; conflict between {s.join(" and ")}.")
 		end
 
 		self.try_get_mproperty_by_name2_cache[mmodule, mtype, name] = res
@@ -176,10 +216,15 @@ class ModelBuilder
 
 	# Helper function to display an error on a node.
 	# Alias for `self.toolcontext.error(n.hot_location, text)`
+	#
+	# This automatically sets `n.is_broken` to true.
 	fun error(n: nullable ANode, text: String)
 	do
 		var l = null
-		if n != null then l = n.hot_location
+		if n != null then
+			l = n.hot_location
+			n.is_broken = true
+		end
 		self.toolcontext.error(l, text)
 	end
 
@@ -208,7 +253,7 @@ class ModelBuilder
 		if res == null then
 			var l = null
 			if n != null then l = n.hot_location
-			self.toolcontext.fatal_error(l, "Fatal Error: {recv} must have a property named {name}.")
+			self.toolcontext.fatal_error(l, "Fatal Error: `{recv}` must have a property named `{name}`.")
 			abort
 		end
 		return res
@@ -220,7 +265,8 @@ class ModelBuilder
 	# FIXME: the name "resolve_mtype" is awful
 	fun resolve_mtype_unchecked(mmodule: MModule, mclassdef: nullable MClassDef, ntype: AType, with_virtual: Bool): nullable MType
 	do
-		var name = ntype.n_id.text
+		var qid = ntype.n_qid
+		var name = qid.n_id.text
 		var res: MType
 
 		# Check virtual type
@@ -228,7 +274,7 @@ class ModelBuilder
 			var prop = try_get_mproperty_by_name(ntype, mclassdef, name).as(nullable MVirtualTypeProp)
 			if prop != null then
 				if not ntype.n_types.is_empty then
-					error(ntype, "Type error: formal type {name} cannot have formal parameters.")
+					error(ntype, "Type Error: formal type `{name}` cannot have formal parameters.")
 				end
 				res = prop.mvirtualtype
 				if ntype.n_kwnullable != null then res = res.as_nullable
@@ -243,7 +289,7 @@ class ModelBuilder
 				if p.name != name then continue
 
 				if not ntype.n_types.is_empty then
-					error(ntype, "Type error: formal type {name} cannot have formal parameters.")
+					error(ntype, "Type Error: formal type `{name}` cannot have formal parameters.")
 				end
 
 				res = p
@@ -254,16 +300,16 @@ class ModelBuilder
 		end
 
 		# Check class
-		var mclass = try_get_mclass_by_name(ntype, mmodule, name)
+		var mclass = try_get_mclass_by_qid(qid, mmodule)
 		if mclass != null then
 			var arity = ntype.n_types.length
 			if arity != mclass.arity then
 				if arity == 0 then
-					error(ntype, "Type error: '{name}' is a generic class.")
+					error(ntype, "Type Error: `{mclass.signature_to_s}` is a generic class.")
 				else if mclass.arity == 0 then
-					error(ntype, "Type error: '{name}' is not a generic class.")
+					error(ntype, "Type Error: `{name}` is not a generic class.")
 				else
-					error(ntype, "Type error: '{name}' has {mclass.arity} parameters ({arity} are provided).")
+					error(ntype, "Type Error: expected {mclass.arity} formal argument(s) for `{mclass.signature_to_s}`; got {arity}.")
 				end
 				return null
 			end
@@ -286,11 +332,88 @@ class ModelBuilder
 			end
 		end
 
-		# If everything fail, then give up :(
-		error(ntype, "Type error: class {name} not found in module {mmodule}.")
+		# If everything fail, then give up with class by proposing things.
+		#
+		# TODO Give hints on formal types (param and virtual)
+		class_not_found(qid, mmodule)
+		ntype.is_broken = true
 		return null
 	end
 
+	# Print an error and suggest hints when the class identified by `qid` in `mmodule` is not found.
+	#
+	# This just print error messages.
+	fun class_not_found(qid: AQclassid, mmodule: MModule)
+	do
+		var name = qid.n_id.text
+		var qname = qid.full_name
+
+		if bad_class_names[mmodule].has(qname) then
+			error(qid, "Error: class `{qname}` not found in module `{mmodule}`.")
+			return
+		end
+		bad_class_names[mmodule].add(qname)
+
+		var all_classes = model.get_mclasses_by_name(name)
+		var hints = new Array[String]
+
+		# Look for conflicting classes.
+		if all_classes != null then for c in all_classes do
+			if not mmodule.is_visible(c.intro_mmodule, c.visibility) then continue
+			if not qid.accept(c) then continue
+			hints.add "`{c.full_name}`"
+		end
+		if hints.length > 1 then
+			error(qid, "Error: ambiguous class name `{qname}` in module `{mmodule}`. Conflicts are between {hints.join(",", " and ")}.")
+			return
+		end
+		hints.clear
+
+		# Look for imported but invisible classes.
+		if all_classes != null then for c in all_classes do
+			if not mmodule.in_importation <= c.intro_mmodule then continue
+			if mmodule.is_visible(c.intro_mmodule, c.visibility) then continue
+			if not qid.accept(c) then continue
+			error(qid, "Error: class `{c.full_name}` not visible in module `{mmodule}`.")
+			return
+		end
+
+		# Look for not imported but known classes from importable modules
+		if all_classes != null then for c in all_classes do
+			if mmodule.in_importation <= c.intro_mmodule then continue
+			if c.intro_mmodule.in_importation <= mmodule then continue
+			if c.visibility <= private_visibility then continue
+			if not qid.accept(c) then continue
+			hints.add "`{c.intro_mmodule.full_name}`"
+		end
+		if hints.not_empty then
+			error(qid, "Error: class `{qname}` not found in module `{mmodule}`. Maybe import {hints.join(",", " or ")}?")
+			return
+		end
+
+		# Look for classes with an approximative name.
+		var bests = new BestDistance[MClass](qname.length - name.length / 2) # limit up to 50% name change
+		for c in model.mclasses do
+			if not mmodule.in_importation <= c.intro_mmodule then continue
+			if not mmodule.is_visible(c.intro_mmodule, c.visibility) then continue
+			var d = qname.levenshtein_distance(c.name)
+			bests.update(d, c)
+			d = qname.levenshtein_distance(c.full_name)
+			bests.update(d, c)
+		end
+		if bests.best_items.not_empty then
+			for c in bests.best_items do hints.add "`{c.full_name}`"
+			error(qid, "Error: class `{qname}` not found in module `{mmodule}`. Did you mean {hints.join(",", " or ")}?")
+			return
+		end
+
+		error(qid, "Error: class `{qname}` not found in module `{mmodule}`.")
+	end
+
+	# List of already reported bad class names.
+	# Used to not perform and repeat hints again and again.
+	private var bad_class_names = new MultiHashMap[MModule, String]
+
 	# Return the static type associated to the node `ntype`.
 	# `mmodule` and `mclassdef` is the context where the call is made (used to understand formal types)
 	# In case of problem, an error is displayed on `ntype` and null is returned.
@@ -305,14 +428,16 @@ class ModelBuilder
 		if mtype isa MGenericType then
 			var mclass = mtype.mclass
 			for i in [0..mclass.arity[ do
-				var bound = mclass.intro.bound_mtype.arguments[i]
+				var intro = mclass.try_intro
+				if intro == null then return null # skip error
+				var bound = intro.bound_mtype.arguments[i]
 				var nt = ntype.n_types[i]
 				var mt = resolve_mtype(mmodule, mclassdef, nt)
 				if mt == null then return null # forward error
 				var anchor
 				if mclassdef != null then anchor = mclassdef.bound_mtype else anchor = null
 				if not check_subtype(nt, mmodule, anchor, mt, bound) then
-					error(nt, "Type error: expected {bound}, got {mt}")
+					error(nt, "Type Error: expected `{bound}`, got `{mt}`.")
 					return null
 				end
 			end
@@ -342,6 +467,22 @@ class ModelBuilder
 	end
 end
 
+redef class ANode
+	# The indication that the node did not pass some semantic verifications.
+	#
+	# This simple flag is set by a given analysis to say that the node is broken and unusable in
+	# an execution.
+	# When a node status is set to broken, it is usually associated with a error message.
+	#
+	# If it is safe to do so, clients of the AST SHOULD just skip broken nodes in their processing.
+	# Clients that do not care about the executability (e.g. metrics) MAY still process the node or
+	# perform specific checks to determinate the validity of the node.
+	#
+	# Note that the broken status is not propagated to parent or children nodes.
+	# e.g. a broken expression used as argument does not make the whole call broken.
+	var is_broken = false is writable
+end
+
 redef class AType
 	# The mtype associated to the node
 	var mtype: nullable MType = null
@@ -395,3 +536,53 @@ redef class ADoc
 		return res
 	end
 end
+
+redef class AQclassid
+	# The name of the package part, if any
+	fun mpackname: nullable String do
+		var nqualified = n_qualified
+		if nqualified == null then return null
+		var nids = nqualified.n_id
+		if nids.length <= 0 then return null
+		return nids[0].text
+	end
+
+	# The name of the module part, if any
+	fun mmodname: nullable String do
+		var nqualified = n_qualified
+		if nqualified == null then return null
+		var nids = nqualified.n_id
+		if nids.length <= 1 then return null
+		return nids[1].text
+	end
+
+	# Does `mclass` match the full qualified name?
+	fun accept(mclass: MClass): Bool
+	do
+		if mclass.name != n_id.text then return false
+		var mpackname = self.mpackname
+		if mpackname != null then
+			var mpackage = mclass.intro_mmodule.mpackage
+			if mpackage == null then return false
+			if mpackage.name != mpackname then return false
+			var mmodname = self.mmodname
+			if mmodname != null and mclass.intro_mmodule.name != mmodname then return false
+		end
+		return true
+	end
+
+	# The pretty name represented by self.
+	fun full_name: String
+	do
+		var res = n_id.text
+		var nqualified = n_qualified
+		if nqualified == null then return res
+		var ncid = nqualified.n_classid
+		if ncid != null then res = ncid.text + "::" + res
+		var nids = nqualified.n_id
+		if nids.not_empty then for n in nids.reverse_iterator do
+			res = n.text + "::" + res
+		end
+		return res
+	end
+end