Fixed #3096: compiler crash involving NoReturn on a method marked as …

…returning Nil
crystal-lang · Aug 4, 2016 · a7aa936 · a7aa936
1 parent 5736f0b
commit a7aa936
Showing 2 changed files with 31 additions and 1 deletion.
diff --git a/spec/compiler/semantic/no_return_spec.cr b/spec/compiler/semantic/no_return_spec.cr
@@ -295,4 +295,28 @@ describe "Semantic: NoReturn" do
       end
       )) { no_return }
   end
+
+  it "types as NoReturn even if Nil return type is forced (#3096)" do
+    assert_type(%(
+      lib LibC
+        fun exit(Int32) : NoReturn
+      end
+
+      def foo : Nil
+        LibC.exit(0)
+        yield
+      end
+
+      def bar(x)
+        x
+      end
+
+      def baz
+        foo { }
+        bar 0
+      end
+
+      baz
+      )) { no_return }
+  end
 end
diff --git a/src/compiler/crystal/semantic/bindings.cr b/src/compiler/crystal/semantic/bindings.cr
@@ -243,7 +243,13 @@ module Crystal
   class Def
     def update(from = nil)
       if freeze_type.try &.nil_type?
-        # Nothing
+        # When we have Nil forced as a return type, NoReturn still
+        # wins, so we must account for this case.
+        # Otherwise we simply keep having the Nil type.
+        computed_type = Type.merge(dependencies)
+        if computed_type.try &.no_return?
+          super
+        end
       else
         super
       end