For #143, handle annotated type variables on contract test

core/src/main/java/com/pholser/junit/quickcheck/internal/ParameterTypeContext.java

@@ -163,15 +163,17 @@ private void addGenerators(List<From> generators) {
     private Generator<?> makeGenerator(Class<? extends Generator> generatorType) {
         // for Ctor/Fields
         Constructor<? extends Generator> ctor = findConstructor(generatorType, Class.class);
-        if (ctor != null)
-            return instantiate(ctor, rawParameterType());
-
-        return instantiate(generatorType);
+        return ctor != null
+            ? instantiate(ctor, rawParameterType())
+            : instantiate(generatorType);
     }
 
     private Class<?> rawParameterType() {
         if (type() instanceof ParameterizedType)
             return (Class<?>) ((ParameterizedType) type()).getRawType();
+        if (type() instanceof TypeVariable<?>)
+            return typeVariables.get(((TypeVariable<?>) type()).getName()).getRawClass();
+
         return (Class<?>) type();
     }
 

generators/src/test/java/com/pholser/junit/quickcheck/ContractTestWithTypeVariableForPropertyParameterTest.java

@@ -0,0 +1,76 @@
+/*
+ The MIT License
+
+ Copyright (c) 2010-2016 Paul R. Holser, Jr.
+
+ Permission is hereby granted, free of charge, to any person obtaining
+ a copy of this software and associated documentation files (the
+ "Software"), to deal in the Software without restriction, including
+ without limitation the rights to use, copy, modify, merge, publish,
+ distribute, sublicense, and/or sell copies of the Software, and to
+ permit persons to whom the Software is furnished to do so, subject to
+ the following conditions:
+
+ The above copyright notice and this permission notice shall be
+ included in all copies or substantial portions of the Software.
+
+ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+
+package com.pholser.junit.quickcheck;
+
+import com.pholser.junit.quickcheck.generator.Ctor;
+import com.pholser.junit.quickcheck.generator.GenerationStatus;
+import com.pholser.junit.quickcheck.generator.Generator;
+import com.pholser.junit.quickcheck.random.SourceOfRandomness;
+import com.pholser.junit.quickcheck.runner.JUnitQuickcheck;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import static org.junit.Assert.*;
+import static org.junit.experimental.results.PrintableResult.*;
+import static org.junit.experimental.results.ResultMatchers.*;
+
+public class ContractTestWithTypeVariableForPropertyParameterTest {
+    public static class TestObject {
+        private final String str;
+
+        public TestObject( String str ) {
+            this.str = str;
+        }
+
+        @Override public String toString() {
+            return str;
+        }
+    }
+
+    public static class G extends Generator<TestObject> {
+        public G() {
+            super(TestObject.class);
+        }
+
+        @Override public TestObject generate(SourceOfRandomness r, GenerationStatus s) {
+            return new TestObject("yermom");
+        }
+    }
+
+    public interface ContractTest<T> {
+        @Property default void testProperty(@From(Ctor.class) T value) {
+            assertEquals(value, value);
+        }
+    }
+
+    @RunWith(JUnitQuickcheck.class)
+    public static class ObjectTest implements ContractTest<TestObject> {
+    }
+
+    @Test public void gitHubIssue143() {
+        assertThat(testResult(ObjectTest.class), isSuccessful());
+    }
+}