diff --git a/samples/sdl/fire.cr b/samples/sdl/fire.cr
index 6af9ad7d5bd1..998b72443d8a 100644
--- a/samples/sdl/fire.cr
+++ b/samples/sdl/fire.cr
@@ -321,7 +321,7 @@ point_count = ARGV.size > 0 ? ARGV[0].to_i : 4
 yellow = YellowColorPattern.new
 magenta = MagentaColorPattern.new
 cyan = CyanColorPattern.new
-rainbow = RainbowColorPattern.new [yellow, magenta, cyan] of ColorPattern
+rainbow = RainbowColorPattern.new [yellow, magenta, cyan]
 
 main_points = [] of MainPoint
 main_points << MainPoint.new(50, 50, -Math::PI / 8, 1.4, yellow)
diff --git a/spec/compiler/codegen/class_spec.cr b/spec/compiler/codegen/class_spec.cr
index abd4da3ba80e..5b7abf38a8ac 100644
--- a/spec/compiler/codegen/class_spec.cr
+++ b/spec/compiler/codegen/class_spec.cr
@@ -504,15 +504,7 @@ describe "Code gen: class" do
 
   it "does to_s for virtual metaclass type (3)" do
     run(%(
-      class Class
-        def name : String
-          {{ @type.name.stringify }}
-        end
-
-        def to_s
-          name
-        end
-      end
+      require "prelude"
 
       class Foo; end
       class Bar < Foo; end
diff --git a/spec/compiler/parser/parser_spec.cr b/spec/compiler/parser/parser_spec.cr
index 2caba5fd3de6..5ebbf3aed14e 100644
--- a/spec/compiler/parser/parser_spec.cr
+++ b/spec/compiler/parser/parser_spec.cr
@@ -9,16 +9,7 @@ private def it_parses(string, expected_node, file = __FILE__, line = __LINE__)
     parser = Parser.new(string)
     parser.filename = "/foo/bar/baz.cr"
     node = parser.parse
-
-    # If it's an Array, map it all to ASTNode (the array might be of a
-    # union that's not exactly ASTNode). Not having to write `[...] of ASTNode`
-    # simplifies testing a bit.
-    local_expected_node = expected_node
-    if local_expected_node.is_a?(Array)
-      local_expected_node = local_expected_node.map(&.as(ASTNode))
-    end
-
-    node.should eq(Expressions.from(local_expected_node))
+    node.should eq(Expressions.from expected_node)
   end
 end
 
@@ -992,7 +983,7 @@ module Crystal
     it_parses "def foo(x); end; x", [Def.new("foo", ["x".arg]), "x".call]
     it_parses "def foo; / /; end", Def.new("foo", body: regex(" "))
 
-    it_parses "\"foo\#{bar}baz\"", StringInterpolation.new(["foo".string, "bar".call, "baz".string] of ASTNode)
+    it_parses "\"foo\#{bar}baz\"", StringInterpolation.new(["foo".string, "bar".call, "baz".string])
     it_parses "qux \"foo\#{bar do end}baz\"", Call.new(nil, "qux", StringInterpolation.new(["foo".string, Call.new(nil, "bar", block: Block.new), "baz".string] of ASTNode))
     it_parses "\"\#{1\n}\"", StringInterpolation.new([1.int32] of ASTNode)
 
diff --git a/spec/compiler/semantic/class_spec.cr b/spec/compiler/semantic/class_spec.cr
index 40eb162c72cc..897e119a64a6 100644
--- a/spec/compiler/semantic/class_spec.cr
+++ b/spec/compiler/semantic/class_spec.cr
@@ -178,7 +178,7 @@ describe "Semantic: class" do
       end
 
       a = Bar.new || Baz.new
-      ") { union_of types["Bar"], types["Baz"] }
+      ") { types["Foo"].virtual_type }
   end
 
   it "types class and subclass as one type" do
diff --git a/spec/compiler/semantic/def_spec.cr b/spec/compiler/semantic/def_spec.cr
index c5e6d4588dee..b689e530fb3a 100644
--- a/spec/compiler/semantic/def_spec.cr
+++ b/spec/compiler/semantic/def_spec.cr
@@ -316,7 +316,7 @@ describe "Semantic: def" do
 
   it "says compile-time type on error" do
     assert_error %(
-      class Foo
+      abstract class Foo
       end
 
       class Bar < Foo
@@ -328,7 +328,7 @@ describe "Semantic: def" do
       class Baz < Foo
       end
 
-      f = Bar.new || Foo.new
+      f = Bar.new || Baz.new
       f.bar
       ),
       "compile-time type is Foo+"
diff --git a/spec/compiler/semantic/struct_spec.cr b/spec/compiler/semantic/struct_spec.cr
index af0af2ba59da..d6452cd474b0 100644
--- a/spec/compiler/semantic/struct_spec.cr
+++ b/spec/compiler/semantic/struct_spec.cr
@@ -39,7 +39,7 @@ describe "Semantic: struct" do
       struct Baz < Foo
       end
 
-      (Bar.new || Baz.new).as(Foo)
+      Bar.new || Baz.new
       ") { types["Foo"].virtual_type! }
   end
 
diff --git a/spec/compiler/semantic/virtual_metaclass_spec.cr b/spec/compiler/semantic/virtual_metaclass_spec.cr
index 41fc904ce58a..bb907f92b380 100644
--- a/spec/compiler/semantic/virtual_metaclass_spec.cr
+++ b/spec/compiler/semantic/virtual_metaclass_spec.cr
@@ -35,7 +35,7 @@ describe "Semantic: virtual metaclass" do
 
   it "allows allocating virtual type when base class is abstract" do
     assert_type("
-      class Foo
+      abstract class Foo
       end
 
       class Bar < Foo
@@ -44,7 +44,7 @@ describe "Semantic: virtual metaclass" do
       class Baz < Foo
       end
 
-      bar = Bar.new || Foo.new
+      bar = Bar.new || Baz.new
       baz = bar.class.allocate
       ") { types["Foo"].virtual_type }
   end
diff --git a/spec/compiler/semantic/virtual_spec.cr b/spec/compiler/semantic/virtual_spec.cr
index 29df3ccd2800..f98fa1536606 100644
--- a/spec/compiler/semantic/virtual_spec.cr
+++ b/spec/compiler/semantic/virtual_spec.cr
@@ -37,7 +37,7 @@ describe "Semantic: virtual" do
       end
 
       a = Bar.new || Baz.new
-      ") { union_of types["Bar"], types["Baz"] }
+      ") { types["Foo"].virtual_type }
   end
 
   it "types class and two subclasses" do
diff --git a/src/compiler/crystal/codegen/cast.cr b/src/compiler/crystal/codegen/cast.cr
index 955b2f74db88..ec276e3bf6b7 100644
--- a/src/compiler/crystal/codegen/cast.cr
+++ b/src/compiler/crystal/codegen/cast.cr
@@ -544,11 +544,6 @@ class Crystal::CodeGenVisitor
   end
 
   def upcast_distinct(value, to_type : MetaclassType | GenericClassInstanceMetaclassType | GenericModuleInstanceMetaclassType | VirtualMetaclassType, from_type)
-    # Special case: union of metaclasses is still represented as a union
-    if from_type.is_a?(MixedUnionType)
-      return load(union_type_id(value))
-    end
-
     value
   end
 
diff --git a/src/compiler/crystal/semantic/literal_expander.cr b/src/compiler/crystal/semantic/literal_expander.cr
index b1e7219e0de2..ed5404ec86a9 100644
--- a/src/compiler/crystal/semantic/literal_expander.cr
+++ b/src/compiler/crystal/semantic/literal_expander.cr
@@ -87,7 +87,7 @@ module Crystal
       exps = Array(ASTNode).new(node.entries.size + 2)
       exps << Assign.new(temp_var.clone, constructor).at(node)
       node.entries.each do |entry|
-        exps << Call.new(temp_var.clone, "[]=", [entry.key.clone, entry.value.clone] of ASTNode).at(node)
+        exps << Call.new(temp_var.clone, "[]=", [entry.key.clone, entry.value.clone]).at(node)
       end
       exps << temp_var.clone
 
diff --git a/src/compiler/crystal/semantic/normalizer.cr b/src/compiler/crystal/semantic/normalizer.cr
index fcd5428f52d4..a65e55986136 100644
--- a/src/compiler/crystal/semantic/normalizer.cr
+++ b/src/compiler/crystal/semantic/normalizer.cr
@@ -260,7 +260,7 @@ module Crystal
 
       # (1); (4)
       if assign
-        Expressions.new([assign, call] of ASTNode).at(node)
+        Expressions.new([assign, call]).at(node)
       else
         call
       end
diff --git a/src/compiler/crystal/semantic/type_merge.cr b/src/compiler/crystal/semantic/type_merge.cr
index dfc931da14ce..e86dfd4e5b21 100644
--- a/src/compiler/crystal/semantic/type_merge.cr
+++ b/src/compiler/crystal/semantic/type_merge.cr
@@ -120,19 +120,6 @@ module Crystal
     end
 
     def type_combine(types)
-      # Modules and types at a higher level in the hierarchy are the ones
-      # that will "delete" deeper types and combine them into virtual
-      # types (or just modules), so we put them in the front for the algorithm.
-      types.sort! do |t1, t2|
-        if t1.module?
-          -1
-        elsif t2.module?
-          1
-        else
-          t1.depth <=> t2.depth
-        end
-      end
-
       all_types = [types.shift] of Type
 
       types.each do |t2|
@@ -346,10 +333,14 @@ private def class_common_ancestor(t1, t2)
     return t1
   end
 
-  # If one type is deeper than the other, check if going up we find
-  # the one in the top, and if so we combine them.
-  # But if they are at the same depth we don't go up.
-  if t1.depth > t2.depth
+  if t1.depth == t2.depth
+    t1_superclass = t1.superclass
+    t2_superclass = t2.superclass
+
+    if t1_superclass && t2_superclass
+      return t1_superclass.common_ancestor(t2_superclass)
+    end
+  elsif t1.depth > t2.depth
     t1_superclass = t1.superclass
     if t1_superclass
       return t1_superclass.common_ancestor(t2)
diff --git a/src/compiler/crystal/tools/playground/agent_instrumentor_transformer.cr b/src/compiler/crystal/tools/playground/agent_instrumentor_transformer.cr
index 7012dbbbf104..822608173f0d 100644
--- a/src/compiler/crystal/tools/playground/agent_instrumentor_transformer.cr
+++ b/src/compiler/crystal/tools/playground/agent_instrumentor_transformer.cr
@@ -96,11 +96,11 @@ module Crystal
 
     def transform(node : MultiAssign)
       node.values = if node.values.size == 1
-                      [instrument(node.values[0])] of ASTNode
+                      [instrument(node.values[0])]
                     else
                       rhs = TupleLiteral.new(node.values)
                       rhs.location = node.location
-                      [instrument(rhs)] of ASTNode
+                      [instrument(rhs)]
                     end
       node
     end