Merge pull request #205 from soutaro/fix-subst

Fix generic method instantiation

lib/steep/ast/types/factory.rb

@@ -219,7 +219,7 @@ def method_type(method_type, self_type:, subst2: nil)
             end
           end
           subst = Interface::Substitution.build(alpha_vars, alpha_types)
-          subst.merge!(subst2) if subst2
+          subst.merge!(subst2, overwrite: true) if subst2
 
           type = Interface::MethodType.new(
             type_params: type_params,
@@ -313,6 +313,7 @@ def expand_alias(type)
         end
 
         def interface(type, private:, self_type: type)
+          Steep.logger.debug { "Factory#interface: #{type}, private=#{private}, self_type=#{self_type}" }
           type = expand_alias(type)
 
           case type
@@ -340,13 +341,15 @@ def interface(type, private:, self_type: type)
               )
 
               definition.methods.each do |name, method|
-                next if method.private? && !private
+                Steep.logger.tagged "method = #{name}" do
+                  next if method.private? && !private
 
-                interface.methods[name] = Interface::Interface::Entry.new(
-                  method_types: method.method_types.map do |type|
-                    method_type(type, self_type: self_type, subst2: subst)
-                  end
-                )
+                  interface.methods[name] = Interface::Interface::Entry.new(
+                    method_types: method.method_types.map do |type|
+                      method_type(type, self_type: self_type, subst2: subst)
+                    end
+                  )
+                end
               end
             end
 

lib/steep/interface/substitution.rb

@@ -90,20 +90,32 @@ def self.build(vars, types = nil, instance_type: AST::Types::Instance.new, modul
 
       def except(vars)
         self.class.new(
-          dictionary: dictionary.reject {|k, _| vars.include?(k) },
+          dictionary: dictionary,
           instance_type: instance_type,
           module_type: module_type,
           self_type: self_type
-        )
+        ).except!(vars)
       end
 
-      def merge!(s)
+      def except!(vars)
+        vars.each do |var|
+          dictionary.delete(var)
+        end
+
+        self
+      end
+
+      def merge!(s, overwrite: false)
         dictionary.transform_values! {|ty| ty.subst(s) }
         dictionary.merge!(s.dictionary) do |key, a, b|
           if a == b
             a
           else
-            raise "Duplicated key on merge!: #{key}, #{a}, #{b}"
+            if overwrite
+              b
+            else
+              raise "Duplicated key on merge!: #{key}, #{a}, #{b} (#{self})"
+            end
           end
         end
 

lib/steep/type_construction.rb

@@ -113,6 +113,7 @@ def update_lvar_env
     end
 
     def check_relation(sub_type:, super_type:, constraints: Subtyping::Constraints.empty)
+      Steep.logger.debug { "check_relation: self:#{self_type} |- #{sub_type} <: #{super_type}" }
       checker.check(Subtyping::Relation.new(sub_type: sub_type, super_type: super_type), self_type: self_type, constraints: constraints)
     end
 

test/type_construction_test.rb

@@ -5379,4 +5379,29 @@ def test_endless_range
       end
     end
   end
+
+  def test_generic_param_rename
+    with_checker(<<-RBS) do |checker|
+interface _Hello[A]
+  def get: [A] () -> A
+end
+
+class TestTest[A]
+  def foo: (_Hello[A]) -> void
+end
+    RBS
+      source = parse_ruby(<<-RUBY)
+class TestTest
+  def foo(x)
+   x.get()
+  end
+end
+      RUBY
+
+      with_standard_construction(checker, source) do |construction, typing|
+        construction.synthesize(source.node)
+        assert_no_error typing
+      end
+    end
+  end
 end