diff --git a/src/main/java/de/tla2b/analysis/SymbolRenamer.java b/src/main/java/de/tla2b/analysis/SymbolRenamer.java
index 56ed582af98f39e9d4707c83e5d8bfee1e0de17c..bc89947fa4573e7dce11432a95784c41b55b7679 100644
--- a/src/main/java/de/tla2b/analysis/SymbolRenamer.java
+++ b/src/main/java/de/tla2b/analysis/SymbolRenamer.java
@@ -21,7 +21,7 @@ import tlc2.tool.BuiltInOPs;
 public class SymbolRenamer extends BuiltInOPs implements TranslationGlobals,
 		ASTConstants {
 
-	private final static Set<String> KEYWORDS = new HashSet<String>();
+	private final static Set<String> KEYWORDS = new HashSet<>();
 	static {
 		KEYWORDS.add("seq");
 		KEYWORDS.add("left");
@@ -71,12 +71,11 @@ public class SymbolRenamer extends BuiltInOPs implements TranslationGlobals,
 		KEYWORDS.add("CONSTRAINTS");
 		KEYWORDS.add("MODEL");
 		KEYWORDS.add("SYSTEM");
-		KEYWORDS.add("MACHINE");
 		KEYWORDS.add("EVENTS");
 		KEYWORDS.add("OPERATIONS");
 	}
 
-	private final static Hashtable<String, String> INFIX_OPERATOR = new Hashtable<String, String>();
+	private final static Hashtable<String, String> INFIX_OPERATOR = new Hashtable<>();
 	static {
 		INFIX_OPERATOR.put("!!", "exclamationmark2");
 		INFIX_OPERATOR.put("??", "questionmark2");
@@ -98,7 +97,7 @@ public class SymbolRenamer extends BuiltInOPs implements TranslationGlobals,
 		INFIX_OPERATOR.put("...", "dot3");
 	}
 
-	private final static Hashtable<String, String> BBUILTIN_OPERATOR = new Hashtable<String, String>();
+	private final static Hashtable<String, String> BBUILTIN_OPERATOR = new Hashtable<>();
 	static {
 		BBUILTIN_OPERATOR.put("+", "plus");
 		BBUILTIN_OPERATOR.put("-", "minus");
@@ -117,8 +116,8 @@ public class SymbolRenamer extends BuiltInOPs implements TranslationGlobals,
 	private final ModuleNode moduleNode;
 	private final Set<OpDefNode> usedDefinitions;
 
-	private final Set<String> globalNames = new HashSet<String>();
-	private final Hashtable<OpDefNode, Set<String>> usedNamesTable = new Hashtable<OpDefNode, Set<String>>();
+	private final Set<String> globalNames = new HashSet<>();
+	private final Hashtable<OpDefNode, Set<String>> usedNamesTable = new Hashtable<>();
 
 	public SymbolRenamer(ModuleNode moduleNode, SpecAnalyser specAnalyser) {
 		this.moduleNode = moduleNode;
diff --git a/src/test/java/de/tla2b/typechecking/standardmodules/TestModuleReals.java b/src/test/java/de/tla2b/typechecking/standardmodules/TestModuleReals.java
index 7926e6a218199162455fe8b1b5695e32b0a10051..6e56bcbbcd1ba75984168d49feb47835edb02258 100644
--- a/src/test/java/de/tla2b/typechecking/standardmodules/TestModuleReals.java
+++ b/src/test/java/de/tla2b/typechecking/standardmodules/TestModuleReals.java
@@ -55,7 +55,7 @@ public class TestModuleReals {
 			+ "EXTENDS Reals \n"
 			+ "ASSUME -1 = -1.0 \n" + "=================================";
 
-		TestTypeChecker t = TestUtil.typeCheckString(module);
+		TestUtil.typeCheckString(module);
 	}
 
 	@Test(expected = TypeErrorException.class)
@@ -100,7 +100,7 @@ public class TestModuleReals {
 	@Test
 	public void testArithmeticOperators() throws TLA2BException {
 		final String module = "-------------- MODULE Testing ----------------\n"
-			+ "EXTENDS Naturals \n"
+			+ "EXTENDS Reals \n"
 			+ "ASSUME 2.0 = 1.0 + 1.0 \n"
 			+ "=================================";
 		TestUtil.typeCheckString(module);
@@ -109,7 +109,7 @@ public class TestModuleReals {
 	@Test(expected = TypeErrorException.class)
 	public void testArithmeticOperatorsException1() throws TLA2BException {
 		final String module = "-------------- MODULE Testing ----------------\n"
-			+ "EXTENDS Naturals \n"
+			+ "EXTENDS Reals \n"
 			+ "ASSUME TRUE = 1.0 + 1.0 \n"
 			+ "=================================";
 		TestUtil.typeCheckString(module);
@@ -118,7 +118,7 @@ public class TestModuleReals {
 	@Test(expected = TypeErrorException.class)
 	public void testArithmeticOperatorsException2() throws TLA2BException {
 		final String module = "-------------- MODULE Testing ----------------\n"
-			+ "EXTENDS Naturals \n"
+			+ "EXTENDS Reals \n"
 			+ "ASSUME 2.0 = 1.0 + 1 \n"
 			+ "=================================";
 		TestUtil.typeCheckString(module);
@@ -127,7 +127,7 @@ public class TestModuleReals {
 	@Test(expected = TypeErrorException.class)
 	public void testArithmeticOperatorsException3() throws TLA2BException {
 		final String module = "-------------- MODULE Testing ----------------\n"
-			+ "EXTENDS Naturals \n"
+			+ "EXTENDS Reals \n"
 			+ "ASSUME 2 = 1.0 + 1.0 \n"
 			+ "=================================";
 		TestUtil.typeCheckString(module);
@@ -147,11 +147,10 @@ public class TestModuleReals {
 	/*
 	 * Interval operator: x .. y
 	 */
-
 	@Test(expected = TypeErrorException.class)
 	public void testDotDotReal() throws TLA2BException {
 		final String module = "-------------- MODULE Testing ----------------\n"
-			+ "EXTENDS Naturals \n"
+			+ "EXTENDS Reals \n"
 			+ "CONSTANTS k \n"
 			+ "ASSUME k = 1.0 .. 3.0 \n"
 			+ "=================================";