Disallow typeof in type restrictions

spec/compiler/semantic/restrictions_spec.cr

@@ -86,16 +86,49 @@ describe "Restrictions" do
       )) { types["Foo"] }
   end
 
-  it "allows typeof as restriction" do
-    assert_type(%(
-      struct Int32
-        def self.foo(x : typeof(self))
-          x
-        end
+  it "errors if using typeof" do
+    assert_error %(
+      def foo(x : typeof(1))
       end
 
-      Int32.foo 1
-      )) { int32 }
+      foo(1)
+      ),
+      "can't use typeof in type restrictions"
+  end
+
+  it "errors if using typeof inside generic type" do
+    assert_error %(
+      class Gen(T)
+      end
+
+      def foo(x : Gen(typeof(1)))
+      end
+
+      foo(Gen(Int32).new)
+      ),
+      "can't use typeof in type restrictions"
+  end
+
+  it "errors if using typeof in block restriction" do
+    assert_error %(
+      def foo(&x : typeof(1) -> )
+        yield 1
+      end
+
+      foo {}
+      ),
+      "can't use 'typeof' here"
+  end
+
+  it "errors if using typeof in block restriction" do
+    assert_error %(
+      def foo(&x : -> typeof(1))
+        yield
+      end
+
+      foo {}
+      ),
+      "can't use typeof in type restriction"
   end
 
   it "passes #278" do

src/compiler/crystal/semantic/call.cr

@@ -941,12 +941,12 @@ class Crystal::Call
 
   private def lookup_node_type(context, node)
     bubbling_exception do
-      context.defining_type.lookup_type(node, self_type: context.instantiated_type.instance_type, free_vars: context.free_vars)
+      context.defining_type.lookup_type(node, self_type: context.instantiated_type.instance_type, free_vars: context.free_vars, allow_typeof: false)
     end
   end
 
   private def lookup_node_type?(context, node)
-    context.defining_type.lookup_type?(node, self_type: context.instantiated_type.instance_type, free_vars: context.free_vars)
+    context.defining_type.lookup_type?(node, self_type: context.instantiated_type.instance_type, free_vars: context.free_vars, allow_typeof: false)
   end
 
   def bubbling_exception

src/compiler/crystal/semantic/restrictions.cr

@@ -351,8 +351,7 @@ module Crystal
     end
 
     def restrict(other : TypeOf, context)
-      lookup_type = self.lookup_type(other, self_type: context.instantiated_type.instance_type)
-      restrict lookup_type, context
+      other.raise "can't use typeof in type restrictions"
     end
 
     def restrict(other : UnionType, context)