Move #to and #to_not to base type

Remove some explicit type restrictions.

src/spectator/expectations/expectation_partial.cr

@@ -4,8 +4,8 @@ module Spectator::Expectations
   # The part of the expectation this class covers is the actual value.
   # This can also cover a block's behavior.
   # Sub-types of this class are returned by the `DSL::ExampleDSL.expect` call.
-  # Sub-types are expected to implement their own variation
-  # of the `#to` and `#not_to` methods.
+  # Sub-types are expected to implement `#eval`,
+  # which returns a corresponding sub-type of `Expectation`.
   abstract struct ExpectationPartial
     # User-friendly string displayed for the actual expression being tested.
     # For instance, in the expectation:
@@ -21,6 +21,27 @@ module Spectator::Expectations
     private def initialize(@label)
     end
 
+    # Asserts that the `#actual` value matches some criteria.
+    # The criteria is defined by the matcher passed to this method.
+    def to(matcher) : Nil
+      report(eval(matcher))
+    end
+
+    # Asserts that the `#actual` value *does not* match some criteria.
+    # This is effectively the opposite of `#to`.
+    def to_not(matcher) : Nil
+      report(eval(matcher, true))
+    end
+
+    # ditto
+    @[AlwaysInline]
+    def not_to(matcher) : Nil
+      to_not(matcher)
+    end
+
+    # Evaluates the expectation and returns it.
+    private abstract def eval(matcher, negated = false) : Expectation
+
     # Reports an expectation to the current harness.
     private def report(expectation : Expectation)
       Internals::Harness.current.report_expectation(expectation)

src/spectator/expectations/value_expectation.cr

@@ -5,7 +5,7 @@ module Spectator::Expectations
   # There are two values - the actual and expected.
   # The actual value is what the SUT returned.
   # The expected value is what the test wants to see.
-  class ValueExpectation(ActualType, ExpectedType) < Expectation
+  class ValueExpectation(ActualType) < Expectation
     # Creates the expectation.
     # The `matched` flag should be true if the matcher is satisfied with the partial.
     # The `negated` flag should be true if the expectation is inverted.
@@ -14,7 +14,7 @@ module Spectator::Expectations
     # the actual and expected value with matcher respectively.
     def initialize(matched, negated,
                    @partial : ValueExpectationPartial(ActualType),
-                   @matcher : Matchers::ValueMatcher(ExpectedType))
+                   @matcher : Matchers::Matcher)
       super(matched, negated)
     end
 

src/spectator/expectations/value_expectation_partial.cr

@@ -21,26 +21,8 @@ module Spectator::Expectations
       super(@actual.to_s)
     end
 
-    # Asserts that the `#actual` value matches some criteria.
-    # The criteria is defined by the matcher passed to this method.
-    def to(matcher : Matchers::ValueMatcher(ExpectedType)) : Nil forall ExpectedType
-      report(eval(matcher))
-    end
-
-    # Asserts that the `#actual` value *does not* match some criteria.
-    # This is effectively the opposite of `#to`.
-    def to_not(matcher : Matchers::ValueMatcher(ExpectedType)) : Nil forall ExpectedType
-      report(eval(matcher, true))
-    end
-
-    # ditto
-    @[AlwaysInline]
-    def not_to(matcher : Matchers::ValueMatcher(ExpectedType)) : Nil forall ExpectedType
-      to_not(matcher)
-    end
-
     # Evaluates the expectation and returns it.
-    private def eval(matcher : Matchers::ValueMatcher(ExpectedType), negated = false) forall ExpectedType
+    private def eval(matcher, negated = false) : Expectation
       matched = matcher.match?(self)
       ValueExpectation.new(matched, negated, self, matcher)
     end