Prevent comparing range arguments with non-compatible types in stubs

Addresses https://github.com/icy-arctic-fox/spectator/issues/48

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fix macro logic to support free variables, 'self', and variants on stubbed methods. [#48](https://github.com/icy-arctic-fox/spectator/issues/48)
 - Fix method stubs used on methods that capture blocks.
 - Fix type name resolution for when using custom types in a mocked typed.
+- Prevent comparing range arguments with non-compatible types in stubs. [#48](https://github.com/icy-arctic-fox/spectator/issues/48)
 
 ### Changed
 - Simplify string representation of mock-related types.

spec/issues/github_issue_48_spec.cr

@@ -38,6 +38,10 @@ Spectator.describe "GitHub Issue #48" do
       block.call(thing)
       block
     end
+
+    def range(r : Range)
+      r
+    end
   end
 
   mock Test, make_nilable: nil
@@ -122,4 +126,10 @@ Spectator.describe "GitHub Issue #48" do
     allow(fake).to receive(:capture).and_return(proc)
     expect(fake.capture(5) { 5 }).to be(proc)
   end
+
+  it "handles range comparisons against non-comparable types" do
+    range = 1..10
+    allow(fake).to receive(:range).and_return(range)
+    expect(fake.range(1..3)).to eq(range)
+  end
 end

src/spectator/mocks/abstract_arguments.cr

@@ -11,13 +11,7 @@ module Spectator
       return false if a.size != b.size
 
       a.zip(b) do |a_value, b_value|
-        if a_value.is_a?(Proc)
+        return false unless compare_values(a_value, b_value)
-          # Using procs as argument matchers isn't supported currently.
-          # Compare directly instead.
-          return false unless a_value == b_value
-        else
-          return false unless a_value === b_value
-        end
       end
       true
     end
@@ -34,15 +28,31 @@ module Spectator
     private def compare_named_tuples(a : NamedTuple, b : NamedTuple)
       a.each do |k, v1|
         v2 = b.fetch(k) { return false }
-        if v1.is_a?(Proc)
+        return false unless compare_values(v1, v2)
-          # Using procs as argument matchers isn't supported currently.
-          # Compare directly instead.
-          return false unless v1 == v2
-        else
-          return false unless v1 === v2
-        end
       end
       true
     end
+
+    # Utility method for comparing two arguments considering special types.
+    # Some types used for case-equality don't work well with unexpected right-hand types.
+    # This can happen when the right side is a massive union of types.
+    private def compare_values(a, b)
+      case a
+      when Proc
+        # Using procs as argument matchers isn't supported currently.
+        # Compare directly instead.
+        a == b
+      when Range
+        # Ranges can only be matched against if their right side is comparable.
+        # Ensure the right side is comparable, otherwise compare directly.
+        if b.is_a?(Comparable(typeof(b)))
+          a === b
+        else
+          a == b
+        end
+      else
+        a === b
+      end
+    end
   end
 end

src/spectator/mocks/arguments.cr

@@ -95,21 +95,13 @@ module Spectator
 
         v1 = positional[i]
         i += 1
-        if v1.is_a?(Proc)
+        return false unless compare_values(v1, v2)
-          return false unless v1 == v2
-        else
-          return false unless v1 === v2
-        end
       end
 
       other.splat.try &.each do |v2|
         v1 = positional.fetch(i) { return false }
         i += 1
-        if v1.is_a?(Proc)
+        return false unless compare_values(v1, v2)
-          return false unless v1 == v2
-        else
-          return false unless v1 === v2
-        end
       end
 
       i == positional.size