Merge branch 'master' into release/0.10

src/spectator/dsl/matchers.cr

@@ -77,7 +77,7 @@ module Spectator::DSL
     # expect(x).to be_a(Int32 | String)
     # ```
     macro be_a(expected)
-      ::Spectator::Matchers::TypeMatcher({{expected}}).new
+      ::Spectator::Matchers::TypeMatcher.create({{expected}})
     end
 
     # Indicates that some value should be of a specified type.

src/spectator/matchers/type_matcher.cr

@@ -4,6 +4,11 @@ module Spectator::Matchers
   # Matcher that tests a value is of a specified type.
   # The values are compared with the `Object#is_a?` method.
   struct TypeMatcher(Expected) < StandardMatcher
+    # Alternate constructor that works with constant types and types from variables.
+    def self.create(type : T.class) forall T
+      TypeMatcher(T).new
+    end
+
     # Short text about the matcher's purpose.
     # This explains what condition satisfies the matcher.
     # The description is used when the one-liner syntax is used.