From 949fa3c3be83de437f84c6acf8b9503347083471 Mon Sep 17 00:00:00 2001
From: Fred Snyder <fsnyder@castwide.com>
Date: Sat, 27 Nov 2021 12:49:11 -0500
Subject: [PATCH] TypeChecker validates aliased namespaces (#497)

---
 lib/solargraph/type_checker.rb          | 11 ++++++++++-
 spec/type_checker/levels/normal_spec.rb | 17 +++++++++++++++--
 2 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/lib/solargraph/type_checker.rb b/lib/solargraph/type_checker.rb
index 4fd8f71a6..cd2183c64 100644
--- a/lib/solargraph/type_checker.rb
+++ b/lib/solargraph/type_checker.rb
@@ -89,7 +89,7 @@ def method_return_type_problems_for pin
       if declared.undefined?
         if pin.return_type.undefined? && rules.require_type_tags?
           result.push Problem.new(pin.location, "Missing @return tag for #{pin.path}", pin: pin)
-        elsif pin.return_type.defined?
+        elsif pin.return_type.defined? && !resolved_constant?(pin)
           result.push Problem.new(pin.location, "Unresolved return type #{pin.return_type} for #{pin.path}", pin: pin)
         elsif rules.must_tag_or_infer? && pin.probe(api_map).undefined?
           result.push Problem.new(pin.location, "Untyped method #{pin.path} could not be inferred")
@@ -111,6 +111,15 @@ def method_return_type_problems_for pin
       result
     end
 
+    # @todo This is not optimal. A better solution would probably be to mix
+    #   namespace alias into types at the ApiMap level.
+    #
+    # @param pin [Pin::Base]
+    # @return [Boolean]
+    def resolved_constant? pin
+      api_map.get_constants('', pin.binder.tag).any? { |pin| pin.name == pin.return_type.namespace && ['Class', 'Module'].include?(pin.return_type.name) }
+    end
+
     def virtual_pin? pin
       pin.location && source_map.source.comment_at?(pin.location.range.ending)
     end
diff --git a/spec/type_checker/levels/normal_spec.rb b/spec/type_checker/levels/normal_spec.rb
index efbeeeaed..9430fe7b0 100644
--- a/spec/type_checker/levels/normal_spec.rb
+++ b/spec/type_checker/levels/normal_spec.rb
@@ -782,7 +782,7 @@ class Foo
           def self.make(arg, *args, **kwargs)
             new([1, 2], *args, **kwargs)
           end
-        
+
           def initialize(timeframe, scope = nil, now: Time.now)
           end
         end
@@ -794,7 +794,7 @@ def initialize(timeframe, scope = nil, now: Time.now)
       checker = type_checker(%(
         def foo(arg1:, arg2:, arg3:, arg4: false)
         end
-        
+
         foo(
           arg1: val1,
           arg2: val2,
@@ -803,5 +803,18 @@ def foo(arg1:, arg2:, arg3:, arg4: false)
       ))
       expect(checker.problems).to be_empty
     end
+
+    it 'validates constant aliases for namespaces' do
+      checker = type_checker(%(
+        class Foo; end
+        Bar = Foo
+
+        # @return [Bar]
+        def foo
+          Bar
+        end
+      ))
+      expect(checker.problems).to be_empty
+    end
   end
 end