fix(template): relax template parameter constraint (#1535)

* test CtTypeReference as Template parameter

* fix: TemplateParemeter proxy can be used for CtTypeReference

src/main/java/spoon/template/Substitution.java

@@ -671,29 +671,31 @@ private static <T> void checkTemplateContracts(CtClass<T> c) {
 			Parameter templateParamAnnotation = f.getAnnotation(Parameter.class);
 			if (templateParamAnnotation != null && !templateParamAnnotation.value().equals("")) {
 				String proxyName = templateParamAnnotation.value();
-				// contract: if value, then the field type must be String
-				if (!f.getType().equals(c.getFactory().Type().STRING)) {
-					throw new TemplateException("proxy template parameter must be typed as String " +  f.getType().getQualifiedName());
-				}
-
-				// contract: the name of the template parameter must correspond to the name of the field
-				// as found, by Pavel, this is not good contract because it prevents easy refactoring of templates
-				// we remove it but keep th commented code in case somebody would come up with this bad idae
-//				if (!f.getSimpleName().equals("_" + f.getAnnotation(Parameter.class).value())) {
-//					throw new TemplateException("the field name of a proxy template parameter must be called _" + f.getSimpleName());
-//				}
-
-				// contract: if a proxy parameter is declared and named "x" (@Parameter("x")), then a type member named "x" must exist.
-				boolean found = false;
-				for (CtTypeMember member: c.getTypeMembers()) {
-					if (member.getSimpleName().equals(proxyName)) {
-						found = true;
+				// contract: if value, then the field type must be String or CtTypeReference
+				String fieldTypeQName = f.getType().getQualifiedName();
+				if (fieldTypeQName.equals(String.class.getName())) {
+					// contract: the name of the template parameter must correspond to the name of the field
+					// as found, by Pavel, this is not good contract because it prevents easy refactoring of templates
+					// we remove it but keep th commented code in case somebody would come up with this bad idae
+//					if (!f.getSimpleName().equals("_" + f.getAnnotation(Parameter.class).value())) {
+//						throw new TemplateException("the field name of a proxy template parameter must be called _" + f.getSimpleName());
+//					}
+
+					// contract: if a proxy parameter is declared and named "x" (@Parameter("x")), then a type member named "x" must exist.
+					boolean found = false;
+					for (CtTypeMember member: c.getTypeMembers()) {
+						if (member.getSimpleName().equals(proxyName)) {
+							found = true;
+						}
 					}
+					if (!found) {
+						throw new TemplateException("if a proxy parameter is declared and named \"" + proxyName + "\", then a type member named \"\" + proxyName + \"\" must exist.");
+					}
+				} else if (fieldTypeQName.equals(CtTypeReference.class.getName())) {
+					//OK it is CtTypeReference
+				} else {
+					throw new TemplateException("proxy template parameter must be typed as String or CtTypeReference, but it is " + fieldTypeQName);
 				}
-				if (!found) {
-					throw new TemplateException("if a proxy parameter is declared and named \"" + proxyName + "\", then a type member named \"\" + proxyName + \"\" must exist.");
-				}
-
 			}
 		}
 	}

src/test/java/spoon/test/template/TemplateTest.java

@@ -21,6 +21,7 @@
 import spoon.reflect.declaration.CtTypeMember;
 import spoon.reflect.factory.Factory;
 import spoon.reflect.reference.CtFieldReference;
+import spoon.reflect.reference.CtTypeReference;
 import spoon.reflect.visitor.ModelConsistencyChecker;
 import spoon.reflect.visitor.filter.NamedElementFilter;
 import spoon.support.compiler.FileSystemFile;
@@ -44,6 +45,7 @@
 import spoon.test.template.testclasses.SubStringTemplate;
 import spoon.test.template.testclasses.SubstituteLiteralTemplate;
 import spoon.test.template.testclasses.SubstituteRootTemplate;
+import spoon.test.template.testclasses.TypeReferenceClassAccessTemplate;
 import spoon.test.template.testclasses.bounds.CheckBound;
 import spoon.test.template.testclasses.bounds.CheckBoundMatcher;
 import spoon.test.template.testclasses.bounds.CheckBoundTemplate;
@@ -62,6 +64,7 @@
 import spoon.test.template.testclasses.types.AClassModel;
 import spoon.test.template.testclasses.types.AnEnumModel;
 import spoon.test.template.testclasses.types.AnIfaceModel;
+import spoon.testing.utils.ModelUtils;
 
 import java.io.File;
 import java.io.Serializable;
@@ -1014,4 +1017,29 @@ public void testAnotherFieldAccessNameSubstitution() throws Exception {
 			assertEquals("java.lang.System.out.println(((x) + (m_x)))", result.getAnonymousExecutables().get(0).getBody().getStatement(0).toString());
 		}
 	}
+
+	@Test
+	public void substituteTypeAccessReference() throws Exception {
+		//contract: the substitution of CtTypeAccess expression ignores actual type arguments if it have to
+		Launcher spoon = new Launcher();
+		spoon.addTemplateResource(new FileSystemFile("./src/test/java/spoon/test/template/testclasses/TypeReferenceClassAccessTemplate.java"));
+		String outputDir = "./target/spooned/test/template/testclasses";
+		spoon.setSourceOutputDirectory(outputDir);
+
+		spoon.buildModel();
+		Factory factory = spoon.getFactory();
+
+		//contract: String value is substituted in substring of literal, named element and reference
+		CtTypeReference<?> typeRef = factory.Type().createReference(TypeReferenceClassAccessTemplate.Example.class);
+		typeRef.addActualTypeArgument(factory.Type().DATE);
+
+		final CtClass<?> result = (CtClass<?>) new TypeReferenceClassAccessTemplate(typeRef).apply(factory.Class().create("spoon.test.template.TypeReferenceClassAccess"));
+		spoon.prettyprint();
+		ModelUtils.canBeBuilt(outputDir, 8);
+		CtMethod<?> method = result.getMethodsByName("someMethod").get(0);
+		assertEquals("spoon.test.template.TypeReferenceClassAccess.Example<java.util.Date>", method.getType().toString());
+		assertEquals("spoon.test.template.TypeReferenceClassAccess.Example<java.util.Date>", method.getParameters().get(0).getType().toString());
+		assertEquals("o = spoon.test.template.TypeReferenceClassAccess.Example.out", method.getBody().getStatement(0).toString());
+		assertEquals("spoon.test.template.TypeReferenceClassAccess.Example<java.util.Date> ret = new spoon.test.template.TypeReferenceClassAccess.Example<java.util.Date>()", method.getBody().getStatement(1).toString());
+	}
 }

src/test/java/spoon/test/template/testclasses/TypeReferenceClassAccessTemplate.java

@@ -0,0 +1,39 @@
+package spoon.test.template.testclasses;
+
+import spoon.reflect.reference.CtTypeReference;
+import spoon.template.ExtensionTemplate;
+import spoon.template.Local;
+import spoon.template.Parameter;
+
+public class TypeReferenceClassAccessTemplate extends ExtensionTemplate {
+	Object o;
+
+	$Type$ someMethod($Type$ param) {
+		o = $Type$.out;
+		$Type$ ret = new $Type$();
+		return ret;
+	}
+
+	@Local
+	public TypeReferenceClassAccessTemplate(CtTypeReference<?> typeRef) {
+		this.typeRef = typeRef;
+	}
+
+	@Parameter("$Type$")
+	CtTypeReference<?> typeRef;
+
+	@Local
+	static class $Type$ {
+		static final String out = "";
+		static long currentTimeMillis(){
+			return 0;
+		}
+	}
+
+	public static class Example<T> {
+		static final String out = "";
+		static long currentTimeMillis(){
+			return 0;
+		}
+	}
+}