diff --git a/modules/lang-painless/src/main/java/org/elasticsearch/painless/AnalyzerCaster.java b/modules/lang-painless/src/main/java/org/elasticsearch/painless/AnalyzerCaster.java
index 588fe8ef5f7..f00a30a62c4 100644
--- a/modules/lang-painless/src/main/java/org/elasticsearch/painless/AnalyzerCaster.java
+++ b/modules/lang-painless/src/main/java/org/elasticsearch/painless/AnalyzerCaster.java
@@ -41,21 +41,37 @@ public final class AnalyzerCaster {
 
         if (actual == def.class) {
             if (expected == boolean.class) {
-                return PainlessCast.unboxTargetType(def.class, Boolean.class, explicit, boolean.class);
+                return PainlessCast.originalTypetoTargetType(def.class, boolean.class, explicit);
             } else if (expected == byte.class) {
-                return PainlessCast.unboxTargetType(def.class, Byte.class, explicit, byte.class);
+                return PainlessCast.originalTypetoTargetType(def.class, byte.class, explicit);
             } else if (expected == short.class) {
-                return PainlessCast.unboxTargetType(def.class, Short.class, explicit, short.class);
+                return PainlessCast.originalTypetoTargetType(def.class, short.class, explicit);
             } else if (expected == char.class) {
-                return PainlessCast.unboxTargetType(def.class, Character.class, explicit, char.class);
+                return PainlessCast.originalTypetoTargetType(def.class, char.class, explicit);
             } else if (expected == int.class) {
-                return PainlessCast.unboxTargetType(def.class, Integer.class, explicit, int.class);
+                return PainlessCast.originalTypetoTargetType(def.class, int.class, explicit);
             } else if (expected == long.class) {
-                return PainlessCast.unboxTargetType(def.class, Long.class, explicit, long.class);
+                return PainlessCast.originalTypetoTargetType(def.class, long.class, explicit);
             } else if (expected == float.class) {
-                return PainlessCast.unboxTargetType(def.class, Float.class, explicit, float.class);
+                return PainlessCast.originalTypetoTargetType(def.class, float.class, explicit);
             } else if (expected == double.class) {
-                return PainlessCast.unboxTargetType(def.class, Double.class, explicit, double.class);
+                return PainlessCast.originalTypetoTargetType(def.class, double.class, explicit);
+            } else if (expected == Boolean.class) {
+                return PainlessCast.originalTypetoTargetType(def.class, Boolean.class, explicit);
+            } else if (expected == Byte.class) {
+                return PainlessCast.originalTypetoTargetType(def.class, Byte.class, explicit);
+            } else if (expected == Short.class) {
+                return PainlessCast.originalTypetoTargetType(def.class, Short.class, explicit);
+            } else if (expected == Character.class) {
+                return PainlessCast.originalTypetoTargetType(def.class, Character.class, explicit);
+            } else if (expected == Integer.class) {
+                return PainlessCast.originalTypetoTargetType(def.class, Integer.class, explicit);
+            } else if (expected == Long.class) {
+                return PainlessCast.originalTypetoTargetType(def.class, Long.class, explicit);
+            } else if (expected == Float.class) {
+                return PainlessCast.originalTypetoTargetType(def.class, Float.class, explicit);
+            } else if (expected == Double.class) {
+                return PainlessCast.originalTypetoTargetType(def.class, Double.class, explicit);
             }
         } else if (actual == Object.class) {
             if (expected == byte.class && explicit && internal) {
diff --git a/modules/lang-painless/src/main/java/org/elasticsearch/painless/Def.java b/modules/lang-painless/src/main/java/org/elasticsearch/painless/Def.java
index 496c2702a8b..c672956cb07 100644
--- a/modules/lang-painless/src/main/java/org/elasticsearch/painless/Def.java
+++ b/modules/lang-painless/src/main/java/org/elasticsearch/painless/Def.java
@@ -623,7 +623,7 @@ public final class Def {
 
     public static boolean defToboolean(final Object value) {
         if (value instanceof Boolean) {
-            return (boolean) value;
+            return (boolean)value;
         } else {
             throw new ClassCastException(
                     "cannot cast def [" + PainlessLookupUtility.typeToUnboxedType(value.getClass()).getCanonicalName() + "] to boolean");
@@ -853,11 +853,27 @@ public final class Def {
 
     // Conversion methods for def to boxed types.
 
+    public static Boolean defToBoolean(final Object value) {
+        if (value == null) {
+            return null;
+        } else if (value instanceof Boolean) {
+            return (Boolean)value;
+        } else {
+            throw new ClassCastException("cannot implicitly cast " +
+                    "def [" + PainlessLookupUtility.typeToUnboxedType(value.getClass()).getCanonicalName() + "] to " +
+                    Boolean.class.getCanonicalName());
+        }
+    }
+
     public static Byte defToByteImplicit(final Object value) {
         if (value == null) {
             return null;
-        } else {
+        } else if (value instanceof Byte) {
             return (Byte)value;
+        } else {
+            throw new ClassCastException("cannot implicitly cast " +
+                    "def [" + PainlessLookupUtility.typeToUnboxedType(value.getClass()).getCanonicalName() + "] to " +
+                    Byte.class.getCanonicalName());
         }
     }
 
@@ -866,16 +882,24 @@ public final class Def {
             return null;
         } else if (value instanceof Byte) {
             return (short)(byte)value;
-        } else {
+        } else if (value instanceof Short) {
             return (Short)value;
+        } else {
+            throw new ClassCastException("cannot implicitly cast " +
+                    "def [" + PainlessLookupUtility.typeToUnboxedType(value.getClass()).getCanonicalName() + "] to " +
+                    Short.class.getCanonicalName());
         }
     }
 
     public static Character defToCharacterImplicit(final Object value) {
         if (value == null) {
             return null;
-        } else {
+        } else if (value instanceof Character) {
             return (Character)value;
+        } else {
+            throw new ClassCastException("cannot implicitly cast " +
+                    "def [" + PainlessLookupUtility.typeToUnboxedType(value.getClass()).getCanonicalName() + "] to " +
+                    Character.class.getCanonicalName());
         }
     }
 
@@ -888,8 +912,12 @@ public final class Def {
             return (int)(short)value;
         } else if (value instanceof Character) {
             return (int)(char)value;
-        } else {
+        } else if (value instanceof Integer) {
             return (Integer)value;
+        } else {
+            throw new ClassCastException("cannot implicitly cast " +
+                    "def [" + PainlessLookupUtility.typeToUnboxedType(value.getClass()).getCanonicalName() + "] to " +
+                    Integer.class.getCanonicalName());
         }
     }
 
@@ -904,8 +932,12 @@ public final class Def {
             return (long)(char)value;
         } else if (value instanceof Integer) {
             return (long)(int)value;
-        } else {
+        } else if (value instanceof Long) {
             return (Long)value;
+        } else {
+            throw new ClassCastException("cannot implicitly cast " +
+                    "def [" + PainlessLookupUtility.typeToUnboxedType(value.getClass()).getCanonicalName() + "] to " +
+                    Long.class.getCanonicalName());
         }
     }
 
@@ -922,8 +954,12 @@ public final class Def {
             return (float)(int)value;
         } else if (value instanceof Long) {
             return (float)(long)value;
-        } else {
+        } else if (value instanceof Float) {
             return (Float)value;
+        } else {
+            throw new ClassCastException("cannot implicitly cast " +
+                    "def [" + PainlessLookupUtility.typeToUnboxedType(value.getClass()).getCanonicalName() + "] to " +
+                    Float.class.getCanonicalName());
         }
     }
 
@@ -942,8 +978,11 @@ public final class Def {
             return (double)(long)value;
         } else if (value instanceof Float) {
             return (double)(float)value;
-        } else {
+        } else if (value instanceof Double) {
             return (Double)value;
+        } else {
+            throw new ClassCastException("cannot implicitly cast " +
+                    "def [" + value.getClass().getCanonicalName() + "] to " + Double.class.getCanonicalName());
         }
     }
 
@@ -952,8 +991,18 @@ public final class Def {
             return null;
         } else if (value instanceof Character) {
             return (byte)(char)value;
-        } else {
+        } else if (
+            value instanceof Byte    ||
+            value instanceof Short   ||
+            value instanceof Integer ||
+            value instanceof Long    ||
+            value instanceof Float   ||
+            value instanceof Double
+        ) {
             return ((Number)value).byteValue();
+        } else {
+            throw new ClassCastException("cannot explicitly cast " +
+                    "def [" + value.getClass().getCanonicalName() + "] to " + Byte.class.getCanonicalName());
         }
     }
 
@@ -962,8 +1011,18 @@ public final class Def {
             return null;
         } else if (value instanceof Character) {
             return (short)(char)value;
-        } else {
+        } else if (
+                value instanceof Byte    ||
+                value instanceof Short   ||
+                value instanceof Integer ||
+                value instanceof Long    ||
+                value instanceof Float   ||
+                value instanceof Double
+        ) {
             return ((Number)value).shortValue();
+        } else {
+            throw new ClassCastException("cannot explicitly cast " +
+                    "def [" + value.getClass().getCanonicalName() + "] to " + Short.class.getCanonicalName());
         }
     }
 
@@ -972,8 +1031,18 @@ public final class Def {
             return null;
         } else if (value instanceof Character) {
             return (Character)value;
-        } else {
+        } else if (
+                value instanceof Byte    ||
+                value instanceof Short   ||
+                value instanceof Integer ||
+                value instanceof Long    ||
+                value instanceof Float   ||
+                value instanceof Double
+        ) {
             return (char)((Number)value).intValue();
+        } else {
+            throw new ClassCastException("cannot explicitly cast " +
+                    "def [" + value.getClass().getCanonicalName() + "] to " + Character.class.getCanonicalName());
         }
     }
 
@@ -982,8 +1051,18 @@ public final class Def {
             return null;
         } else if (value instanceof Character) {
             return (int)(char)value;
-        } else {
+        } else if (
+                value instanceof Byte    ||
+                value instanceof Short   ||
+                value instanceof Integer ||
+                value instanceof Long    ||
+                value instanceof Float   ||
+                value instanceof Double
+        ) {
             return ((Number)value).intValue();
+        } else {
+            throw new ClassCastException("cannot explicitly cast " +
+                    "def [" + value.getClass().getCanonicalName() + "] to " + Integer.class.getCanonicalName());
         }
     }
 
@@ -992,8 +1071,18 @@ public final class Def {
             return null;
         } else if (value instanceof Character) {
             return (long)(char)value;
-        } else {
+        } else if (
+                value instanceof Byte    ||
+                value instanceof Short   ||
+                value instanceof Integer ||
+                value instanceof Long    ||
+                value instanceof Float   ||
+                value instanceof Double
+        ) {
             return ((Number)value).longValue();
+        } else {
+            throw new ClassCastException("cannot explicitly cast " +
+                    "def [" + value.getClass().getCanonicalName() + "] to " + Long.class.getCanonicalName());
         }
     }
 
@@ -1002,8 +1091,18 @@ public final class Def {
             return null;
         } else if (value instanceof Character) {
             return (float)(char)value;
-        } else {
+        } else if (
+                value instanceof Byte    ||
+                value instanceof Short   ||
+                value instanceof Integer ||
+                value instanceof Long    ||
+                value instanceof Float   ||
+                value instanceof Double
+        ) {
             return ((Number)value).floatValue();
+        } else {
+            throw new ClassCastException("cannot explicitly cast " +
+                    "def [" + value.getClass().getCanonicalName() + "] to " + Float.class.getCanonicalName());
         }
     }
 
@@ -1012,8 +1111,18 @@ public final class Def {
             return null;
         } else if (value instanceof Character) {
             return (double)(char)value;
-        } else {
+        } else if (
+                value instanceof Byte    ||
+                value instanceof Short   ||
+                value instanceof Integer ||
+                value instanceof Long    ||
+                value instanceof Float   ||
+                value instanceof Double
+        ) {
             return ((Number)value).doubleValue();
+        } else {
+            throw new ClassCastException("cannot explicitly cast " +
+                    "def [" + value.getClass().getCanonicalName() + "] to " + Double.class.getCanonicalName());
         }
     }
 
diff --git a/modules/lang-painless/src/main/java/org/elasticsearch/painless/MethodWriter.java b/modules/lang-painless/src/main/java/org/elasticsearch/painless/MethodWriter.java
index b03587ba5e9..a2433689db3 100644
--- a/modules/lang-painless/src/main/java/org/elasticsearch/painless/MethodWriter.java
+++ b/modules/lang-painless/src/main/java/org/elasticsearch/painless/MethodWriter.java
@@ -39,7 +39,22 @@ import java.util.List;
 
 import static org.elasticsearch.painless.WriterConstants.CHAR_TO_STRING;
 import static org.elasticsearch.painless.WriterConstants.DEF_BOOTSTRAP_HANDLE;
-import static org.elasticsearch.painless.WriterConstants.DEF_TO_BOOLEAN;
+import static org.elasticsearch.painless.WriterConstants.DEF_TO_B_BOOLEAN;
+import static org.elasticsearch.painless.WriterConstants.DEF_TO_B_BYTE_EXPLICIT;
+import static org.elasticsearch.painless.WriterConstants.DEF_TO_B_BYTE_IMPLICIT;
+import static org.elasticsearch.painless.WriterConstants.DEF_TO_B_CHARACTER_EXPLICIT;
+import static org.elasticsearch.painless.WriterConstants.DEF_TO_B_CHARACTER_IMPLICIT;
+import static org.elasticsearch.painless.WriterConstants.DEF_TO_B_DOUBLE_EXPLICIT;
+import static org.elasticsearch.painless.WriterConstants.DEF_TO_B_DOUBLE_IMPLICIT;
+import static org.elasticsearch.painless.WriterConstants.DEF_TO_B_FLOAT_EXPLICIT;
+import static org.elasticsearch.painless.WriterConstants.DEF_TO_B_FLOAT_IMPLICIT;
+import static org.elasticsearch.painless.WriterConstants.DEF_TO_B_INTEGER_EXPLICIT;
+import static org.elasticsearch.painless.WriterConstants.DEF_TO_B_INTEGER_IMPLICIT;
+import static org.elasticsearch.painless.WriterConstants.DEF_TO_B_LONG_EXPLICIT;
+import static org.elasticsearch.painless.WriterConstants.DEF_TO_B_LONG_IMPLICIT;
+import static org.elasticsearch.painless.WriterConstants.DEF_TO_B_SHORT_EXPLICIT;
+import static org.elasticsearch.painless.WriterConstants.DEF_TO_B_SHORT_IMPLICIT;
+import static org.elasticsearch.painless.WriterConstants.DEF_TO_P_BOOLEAN;
 import static org.elasticsearch.painless.WriterConstants.DEF_TO_P_BYTE_EXPLICIT;
 import static org.elasticsearch.painless.WriterConstants.DEF_TO_P_BYTE_IMPLICIT;
 import static org.elasticsearch.painless.WriterConstants.DEF_TO_P_CHAR_EXPLICIT;
@@ -143,42 +158,56 @@ public final class MethodWriter extends GeneratorAdapter {
                 unbox(getType(cast.unboxOriginalType));
                 writeCast(cast.originalType, cast.targetType);
             } else if (cast.unboxTargetType != null) {
-                if (cast.originalType == def.class) {
-                    if (cast.explicitCast) {
-                        if      (cast.targetType == Boolean.class)   invokeStatic(DEF_UTIL_TYPE, DEF_TO_BOOLEAN);
-                        else if (cast.targetType == Byte.class)      invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_BYTE_EXPLICIT);
-                        else if (cast.targetType == Short.class)     invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_SHORT_EXPLICIT);
-                        else if (cast.targetType == Character.class) invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_CHAR_EXPLICIT);
-                        else if (cast.targetType == Integer.class)   invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_INT_EXPLICIT);
-                        else if (cast.targetType == Long.class)      invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_LONG_EXPLICIT);
-                        else if (cast.targetType == Float.class)     invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_FLOAT_EXPLICIT);
-                        else if (cast.targetType == Double.class)    invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_DOUBLE_EXPLICIT);
-                        else {
-                            throw new IllegalStateException("Illegal tree structure.");
-                        }
-                    } else {
-                        if      (cast.targetType == Boolean.class)   invokeStatic(DEF_UTIL_TYPE, DEF_TO_BOOLEAN);
-                        else if (cast.targetType == Byte.class)      invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_BYTE_IMPLICIT);
-                        else if (cast.targetType == Short.class)     invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_SHORT_IMPLICIT);
-                        else if (cast.targetType == Character.class) invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_CHAR_IMPLICIT);
-                        else if (cast.targetType == Integer.class)   invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_INT_IMPLICIT);
-                        else if (cast.targetType == Long.class)      invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_LONG_IMPLICIT);
-                        else if (cast.targetType == Float.class)     invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_FLOAT_IMPLICIT);
-                        else if (cast.targetType == Double.class)    invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_DOUBLE_IMPLICIT);
-                        else {
-                            throw new IllegalStateException("Illegal tree structure.");
-                        }
-                    }
-                } else {
-                    writeCast(cast.originalType, cast.targetType);
-                    unbox(getType(cast.unboxTargetType));
-                }
+                writeCast(cast.originalType, cast.targetType);
+                unbox(getType(cast.unboxTargetType));
             } else if (cast.boxOriginalType != null) {
                 box(getType(cast.boxOriginalType));
                 writeCast(cast.originalType, cast.targetType);
             } else if (cast.boxTargetType != null) {
                 writeCast(cast.originalType, cast.targetType);
                 box(getType(cast.boxTargetType));
+            } else if (cast.originalType == def.class) {
+                if (cast.explicitCast) {
+                    if      (cast.targetType == boolean.class)   invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_BOOLEAN);
+                    else if (cast.targetType == byte.class)      invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_BYTE_EXPLICIT);
+                    else if (cast.targetType == short.class)     invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_SHORT_EXPLICIT);
+                    else if (cast.targetType == char.class)      invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_CHAR_EXPLICIT);
+                    else if (cast.targetType == int.class)       invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_INT_EXPLICIT);
+                    else if (cast.targetType == long.class)      invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_LONG_EXPLICIT);
+                    else if (cast.targetType == float.class)     invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_FLOAT_EXPLICIT);
+                    else if (cast.targetType == double.class)    invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_DOUBLE_EXPLICIT);
+                    else if (cast.targetType == Boolean.class)   invokeStatic(DEF_UTIL_TYPE, DEF_TO_B_BOOLEAN);
+                    else if (cast.targetType == Byte.class)      invokeStatic(DEF_UTIL_TYPE, DEF_TO_B_BYTE_EXPLICIT);
+                    else if (cast.targetType == Short.class)     invokeStatic(DEF_UTIL_TYPE, DEF_TO_B_SHORT_EXPLICIT);
+                    else if (cast.targetType == Character.class) invokeStatic(DEF_UTIL_TYPE, DEF_TO_B_CHARACTER_EXPLICIT);
+                    else if (cast.targetType == Integer.class)   invokeStatic(DEF_UTIL_TYPE, DEF_TO_B_INTEGER_EXPLICIT);
+                    else if (cast.targetType == Long.class)      invokeStatic(DEF_UTIL_TYPE, DEF_TO_B_LONG_EXPLICIT);
+                    else if (cast.targetType == Float.class)     invokeStatic(DEF_UTIL_TYPE, DEF_TO_B_FLOAT_EXPLICIT);
+                    else if (cast.targetType == Double.class)    invokeStatic(DEF_UTIL_TYPE, DEF_TO_B_DOUBLE_EXPLICIT);
+                    else {
+                        writeCast(cast.originalType, cast.targetType);
+                    }
+                } else {
+                    if      (cast.targetType == boolean.class)   invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_BOOLEAN);
+                    else if (cast.targetType == byte.class)      invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_BYTE_IMPLICIT);
+                    else if (cast.targetType == short.class)     invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_SHORT_IMPLICIT);
+                    else if (cast.targetType == char.class)      invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_CHAR_IMPLICIT);
+                    else if (cast.targetType == int.class)       invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_INT_IMPLICIT);
+                    else if (cast.targetType == long.class)      invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_LONG_IMPLICIT);
+                    else if (cast.targetType == float.class)     invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_FLOAT_IMPLICIT);
+                    else if (cast.targetType == double.class)    invokeStatic(DEF_UTIL_TYPE, DEF_TO_P_DOUBLE_IMPLICIT);
+                    else if (cast.targetType == Boolean.class)   invokeStatic(DEF_UTIL_TYPE, DEF_TO_B_BOOLEAN);
+                    else if (cast.targetType == Byte.class)      invokeStatic(DEF_UTIL_TYPE, DEF_TO_B_BYTE_IMPLICIT);
+                    else if (cast.targetType == Short.class)     invokeStatic(DEF_UTIL_TYPE, DEF_TO_B_SHORT_IMPLICIT);
+                    else if (cast.targetType == Character.class) invokeStatic(DEF_UTIL_TYPE, DEF_TO_B_CHARACTER_IMPLICIT);
+                    else if (cast.targetType == Integer.class)   invokeStatic(DEF_UTIL_TYPE, DEF_TO_B_INTEGER_IMPLICIT);
+                    else if (cast.targetType == Long.class)      invokeStatic(DEF_UTIL_TYPE, DEF_TO_B_LONG_IMPLICIT);
+                    else if (cast.targetType == Float.class)     invokeStatic(DEF_UTIL_TYPE, DEF_TO_B_FLOAT_IMPLICIT);
+                    else if (cast.targetType == Double.class)    invokeStatic(DEF_UTIL_TYPE, DEF_TO_B_DOUBLE_IMPLICIT);
+                    else {
+                        writeCast(cast.originalType, cast.targetType);
+                    }
+                }
             } else {
                 writeCast(cast.originalType, cast.targetType);
             }
diff --git a/modules/lang-painless/src/main/java/org/elasticsearch/painless/WriterConstants.java b/modules/lang-painless/src/main/java/org/elasticsearch/painless/WriterConstants.java
index 78125d7e750..12112684f27 100644
--- a/modules/lang-painless/src/main/java/org/elasticsearch/painless/WriterConstants.java
+++ b/modules/lang-painless/src/main/java/org/elasticsearch/painless/WriterConstants.java
@@ -124,7 +124,7 @@ public final class WriterConstants {
 
     public static final Type DEF_UTIL_TYPE = Type.getType(Def.class);
 
-    public static final Method DEF_TO_BOOLEAN = getAsmMethod(boolean.class, "defToboolean", Object.class);
+    public static final Method DEF_TO_P_BOOLEAN = getAsmMethod(boolean.class, "defToboolean", Object.class);
 
     public static final Method DEF_TO_P_BYTE_IMPLICIT   = getAsmMethod(byte.class   , "defTobyteImplicit"   , Object.class);
     public static final Method DEF_TO_P_SHORT_IMPLICIT  = getAsmMethod(short.class  , "defToshortImplicit"  , Object.class);
@@ -141,6 +141,8 @@ public final class WriterConstants {
     public static final Method DEF_TO_P_FLOAT_EXPLICIT  = getAsmMethod(float.class  , "defTofloatExplicit"  , Object.class);
     public static final Method DEF_TO_P_DOUBLE_EXPLICIT = getAsmMethod(double.class , "defTodoubleExplicit" , Object.class);
 
+    public static final Method DEF_TO_B_BOOLEAN = getAsmMethod(Boolean.class, "defToBoolean", Object.class);
+
     public static final Method DEF_TO_B_BYTE_IMPLICIT      = getAsmMethod(Byte.class      , "defToByteImplicit"      , Object.class);
     public static final Method DEF_TO_B_SHORT_IMPLICIT     = getAsmMethod(Short.class     , "defToShortImplicit"     , Object.class);
     public static final Method DEF_TO_B_CHARACTER_IMPLICIT = getAsmMethod(Character.class , "defToCharacterImplicit" , Object.class);
diff --git a/modules/lang-painless/src/test/java/org/elasticsearch/painless/DefCastTests.java b/modules/lang-painless/src/test/java/org/elasticsearch/painless/DefCastTests.java
index 2add69989b1..015176a43c3 100644
--- a/modules/lang-painless/src/test/java/org/elasticsearch/painless/DefCastTests.java
+++ b/modules/lang-painless/src/test/java/org/elasticsearch/painless/DefCastTests.java
@@ -335,4 +335,340 @@ public class DefCastTests extends ScriptTestCase {
         assertEquals((double)0, exec("def d = Double.valueOf(0); double b = (double)d; b"));
         expectScriptThrows(ClassCastException.class, () -> exec("def d = new ArrayList(); double b = (double)d;"));
     }
+
+    public void testdefToBooleanImplicit() {
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = 'string'; Boolean b = d;"));
+        assertEquals(true, exec("def d = true; Boolean b = d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (byte)0; Boolean b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (short)0; Boolean b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (char)0; Boolean b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (int)0; Boolean b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (long)0; Boolean b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (float)0; Boolean b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (double)0; Boolean b = d;"));
+        assertEquals(false, exec("def d = Boolean.valueOf(false); Boolean b = d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Byte.valueOf(0); Boolean b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Short.valueOf(0); Boolean b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Character.valueOf(0); Boolean b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Integer.valueOf(0); Boolean b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Long.valueOf(0); Boolean b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Float.valueOf(0); Boolean b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Double.valueOf(0); Boolean b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = new ArrayList(); Boolean b = d;"));
+    }
+
+    public void testdefToByteImplicit() {
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = 'string'; Byte b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = true; Byte b = d;"));
+        assertEquals((byte)0, exec("def d = (byte)0; Byte b = d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (short)0; Byte b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (char)0; Byte b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (int)0; Byte b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (long)0; Byte b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (float)0; Byte b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (double)0; Byte b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Boolean.valueOf(true); Byte b = d;"));
+        assertEquals((byte)0, exec("def d = Byte.valueOf(0); Byte b = d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Short.valueOf(0); Byte b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Character.valueOf(0); Byte b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Integer.valueOf(0); Byte b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Long.valueOf(0); Byte b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Float.valueOf(0); Byte b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Double.valueOf(0); Byte b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = new ArrayList(); Byte b = d;"));
+    }
+
+    public void testdefToShortImplicit() {
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = 'string'; Short b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = true; Short b = d;"));
+        assertEquals((short)0, exec("def d = (byte)0; Short b = d; b"));
+        assertEquals((short)0, exec("def d = (short)0; Short b = d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (char)0; Short b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (int)0; Short b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (long)0; Short b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (float)0; Short b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (double)0; Short b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Boolean.valueOf(true); Short b = d;"));
+        assertEquals((short)0, exec("def d = Byte.valueOf(0); Short b = d; b"));
+        assertEquals((short)0, exec("def d = Short.valueOf(0); Short b = d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Character.valueOf(0); Short b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Integer.valueOf(0); Short b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Long.valueOf(0); Short b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Float.valueOf(0); Short b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Double.valueOf(0); Short b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = new ArrayList(); Short b = d;"));
+    }
+
+    public void testdefToCharacterImplicit() {
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = 'string'; Character b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = true; Character b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (byte)0; Character b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (short)0; Character b = d;"));
+        assertEquals((char)0, exec("def d = (char)0; Character b = d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (int)0; Character b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (long)0; Character b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (float)0; Character b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (double)0; Character b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Boolean.valueOf(true); Character b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Byte.valueOf(0); Character b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Short.valueOf(0); Character b = d;"));
+        assertEquals((char)0, exec("def d = Character.valueOf(0); Character b = d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Integer.valueOf(0); Character b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Long.valueOf(0); Character b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Float.valueOf(0); Character b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Double.valueOf(0); Character b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = new ArrayList(); Character b = d;"));
+    }
+
+    public void testdefToIntegerImplicit() {
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = 'string'; Integer b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = true; Integer b = d;"));
+        assertEquals(0, exec("def d = (byte)0; Integer b = d; b"));
+        assertEquals(0, exec("def d = (short)0; Integer b = d; b"));
+        assertEquals(0, exec("def d = (char)0; Integer b = d; b"));
+        assertEquals(0, exec("def d = 0; Integer b = d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (long)0; Integer b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (float)0; Integer b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (double)0; Integer b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Boolean.valueOf(true); Integer b = d;"));
+        assertEquals(0, exec("def d = Byte.valueOf(0); Integer b = d; b"));
+        assertEquals(0, exec("def d = Short.valueOf(0); Integer b = d; b"));
+        assertEquals(0, exec("def d = Character.valueOf(0); Integer b = d; b"));
+        assertEquals(0, exec("def d = Integer.valueOf(0); Integer b = d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Long.valueOf(0); Integer b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Float.valueOf(0); Integer b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Double.valueOf(0); Integer b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = new ArrayList(); Integer b = d;"));
+    }
+
+    public void testdefToLongImplicit() {
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = 'string'; Long b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = true; Long b = d;"));
+        assertEquals((long)0, exec("def d = (byte)0; Long b = d; b"));
+        assertEquals((long)0, exec("def d = (short)0; Long b = d; b"));
+        assertEquals((long)0, exec("def d = (char)0; Long b = d; b"));
+        assertEquals((long)0, exec("def d = 0; Long b = d; b"));
+        assertEquals((long)0, exec("def d = (long)0; Long b = d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (float)0; Long b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (double)0; Long b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Boolean.valueOf(true); Long b = d;"));
+        assertEquals((long)0, exec("def d = Byte.valueOf(0); Long b = d; b"));
+        assertEquals((long)0, exec("def d = Short.valueOf(0); Long b = d; b"));
+        assertEquals((long)0, exec("def d = Character.valueOf(0); Long b = d; b"));
+        assertEquals((long)0, exec("def d = Integer.valueOf(0); Long b = d; b"));
+        assertEquals((long)0, exec("def d = Long.valueOf(0); Long b = d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Float.valueOf(0); Long b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Double.valueOf(0); Long b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = new ArrayList(); Long b = d;"));
+    }
+
+    public void testdefToFloatImplicit() {
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = 'string'; Float b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = true; Float b = d;"));
+        assertEquals((float)0, exec("def d = (byte)0; Float b = d; b"));
+        assertEquals((float)0, exec("def d = (short)0; Float b = d; b"));
+        assertEquals((float)0, exec("def d = (char)0; Float b = d; b"));
+        assertEquals((float)0, exec("def d = 0; Float b = d; b"));
+        assertEquals((float)0, exec("def d = (long)0; Float b = d; b"));
+        assertEquals((float)0, exec("def d = (float)0; Float b = d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (double)0; Float b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Boolean.valueOf(true); Float b = d;"));
+        assertEquals((float)0, exec("def d = Byte.valueOf(0); Float b = d; b"));
+        assertEquals((float)0, exec("def d = Short.valueOf(0); Float b = d; b"));
+        assertEquals((float)0, exec("def d = Character.valueOf(0); Float b = d; b"));
+        assertEquals((float)0, exec("def d = Integer.valueOf(0); Float b = d; b"));
+        assertEquals((float)0, exec("def d = Long.valueOf(0); Float b = d; b"));
+        assertEquals((float)0, exec("def d = Float.valueOf(0); Float b = d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Double.valueOf(0); Float b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = new ArrayList(); Float b = d;"));
+    }
+    
+    public void testdefToDoubleImplicit() {
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = 'string'; Double b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = true; Double b = d;"));
+        assertEquals((double)0, exec("def d = (byte)0; Double b = d; b"));
+        assertEquals((double)0, exec("def d = (short)0; Double b = d; b"));
+        assertEquals((double)0, exec("def d = (char)0; Double b = d; b"));
+        assertEquals((double)0, exec("def d = 0; Double b = d; b"));
+        assertEquals((double)0, exec("def d = (long)0; Double b = d; b"));
+        assertEquals((double)0, exec("def d = (float)0; Double b = d; b"));
+        assertEquals((double)0, exec("def d = (double)0; Double b = d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Boolean.valueOf(true); Double b = d;"));
+        assertEquals((double)0, exec("def d = Byte.valueOf(0); Double b = d; b"));
+        assertEquals((double)0, exec("def d = Short.valueOf(0); Double b = d; b"));
+        assertEquals((double)0, exec("def d = Character.valueOf(0); Double b = d; b"));
+        assertEquals((double)0, exec("def d = Integer.valueOf(0); Double b = d; b"));
+        assertEquals((double)0, exec("def d = Long.valueOf(0); Double b = d; b"));
+        assertEquals((double)0, exec("def d = Float.valueOf(0); Double b = d; b"));
+        assertEquals((double)0, exec("def d = Double.valueOf(0); Double b = d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = new ArrayList(); Double b = d;"));
+    }
+
+    public void testdefToBooleanExplicit() {
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = 'string'; Boolean b = (Boolean)d;"));
+        assertEquals(true, exec("def d = true; Boolean b = (Boolean)d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (byte)0; Boolean b = (Boolean)d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (short)0; Boolean b = (Boolean)d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (char)0; Boolean b = (Boolean)d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (int)0; Boolean b = (Boolean)d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (long)0; Boolean b = (Boolean)d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (float)0; Boolean b = (Boolean)d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = (double)0; Boolean b = (Boolean)d;"));
+        assertEquals(false, exec("def d = Boolean.valueOf(false); Boolean b = (Boolean)d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Byte.valueOf(0); Boolean b = (Boolean)d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Short.valueOf(0); Boolean b = (Boolean)d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Character.valueOf(0); Boolean b = (Boolean)d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Integer.valueOf(0); Boolean b = (Boolean)d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Long.valueOf(0); Boolean b = (Boolean)d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Float.valueOf(0); Boolean b = (Boolean)d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Double.valueOf(0); Boolean b = (Boolean)d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = new ArrayList(); Boolean b = (Boolean)d;"));
+    }
+
+    public void testdefToByteExplicit() {
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = 'string'; Byte b = (Byte)d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = true; Byte b = (Byte)d;"));
+        assertEquals((byte)0, exec("def d = (byte)0; Byte b = (Byte)d; b"));
+        assertEquals((byte)0, exec("def d = (short)0; Byte b = (Byte)d; b"));
+        assertEquals((byte)0, exec("def d = (char)0; Byte b = (Byte)d; b"));
+        assertEquals((byte)0, exec("def d = 0; Byte b = (Byte)d; b"));
+        assertEquals((byte)0, exec("def d = (long)0; Byte b = (Byte)d; b"));
+        assertEquals((byte)0, exec("def d = (float)0; Byte b = (Byte)d; b"));
+        assertEquals((byte)0, exec("def d = (double)0; Byte b = (Byte)d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Boolean.valueOf(true); Byte b = d;"));
+        assertEquals((byte)0, exec("def d = Byte.valueOf(0); Byte b = (Byte)d; b"));
+        assertEquals((byte)0, exec("def d = Short.valueOf(0); Byte b = (Byte)d; b"));
+        assertEquals((byte)0, exec("def d = Character.valueOf(0); Byte b = (Byte)d; b"));
+        assertEquals((byte)0, exec("def d = Integer.valueOf(0); Byte b = (Byte)d; b"));
+        assertEquals((byte)0, exec("def d = Long.valueOf(0); Byte b = (Byte)d; b"));
+        assertEquals((byte)0, exec("def d = Float.valueOf(0); Byte b = (Byte)d; b"));
+        assertEquals((byte)0, exec("def d = Double.valueOf(0); Byte b = (Byte)d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = new ArrayList(); Byte b = (Byte)d;"));
+    }
+
+    public void testdefToShortExplicit() {
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = 'string'; Short b = (Short)d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = true; Short b = (Short)d;"));
+        assertEquals((short)0, exec("def d = (byte)0; Short b = (Short)d; b"));
+        assertEquals((short)0, exec("def d = (short)0; Short b = (Short)d; b"));
+        assertEquals((short)0, exec("def d = (char)0; Short b = (Short)d; b"));
+        assertEquals((short)0, exec("def d = 0; Short b = (Short)d; b"));
+        assertEquals((short)0, exec("def d = (long)0; Short b = (Short)d; b"));
+        assertEquals((short)0, exec("def d = (float)0; Short b = (Short)d; b"));
+        assertEquals((short)0, exec("def d = (double)0; Short b = (Short)d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Boolean.valueOf(true); Short b = d;"));
+        assertEquals((short)0, exec("def d = Byte.valueOf(0); Short b = (Short)d; b"));
+        assertEquals((short)0, exec("def d = Short.valueOf(0); Short b = (Short)d; b"));
+        assertEquals((short)0, exec("def d = Character.valueOf(0); Short b = (Short)d; b"));
+        assertEquals((short)0, exec("def d = Integer.valueOf(0); Short b = (Short)d; b"));
+        assertEquals((short)0, exec("def d = Long.valueOf(0); Short b = (Short)d; b"));
+        assertEquals((short)0, exec("def d = Float.valueOf(0); Short b = (Short)d; b"));
+        assertEquals((short)0, exec("def d = Double.valueOf(0); Short b = (Short)d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = new ArrayList(); Short b = (Short)d;"));
+    }
+
+    public void testdefToCharacterExplicit() {
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = 'string'; Character b = (Character)d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = true; Character b = (Character)d;"));
+        assertEquals((char)0, exec("def d = (byte)0; Character b = (Character)d; b"));
+        assertEquals((char)0, exec("def d = (short)0; Character b = (Character)d; b"));
+        assertEquals((char)0, exec("def d = (char)0; Character b = (Character)d; b"));
+        assertEquals((char)0, exec("def d = 0; Character b = (Character)d; b"));
+        assertEquals((char)0, exec("def d = (long)0; Character b = (Character)d; b"));
+        assertEquals((char)0, exec("def d = (float)0; Character b = (Character)d; b"));
+        assertEquals((char)0, exec("def d = (double)0; Character b = (Character)d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Boolean.valueOf(true); Character b = d;"));
+        assertEquals((char)0, exec("def d = Byte.valueOf(0); Character b = (Character)d; b"));
+        assertEquals((char)0, exec("def d = Short.valueOf(0); Character b = (Character)d; b"));
+        assertEquals((char)0, exec("def d = Character.valueOf(0); Character b = (Character)d; b"));
+        assertEquals((char)0, exec("def d = Integer.valueOf(0); Character b = (Character)d; b"));
+        assertEquals((char)0, exec("def d = Long.valueOf(0); Character b = (Character)d; b"));
+        assertEquals((char)0, exec("def d = Float.valueOf(0); Character b = (Character)d; b"));
+        assertEquals((char)0, exec("def d = Double.valueOf(0); Character b = (Character)d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = new ArrayList(); Character b = (Character)d;"));
+    }
+
+    public void testdefToIntegerExplicit() {
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = 'string'; Integer b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = true; Integer b = (Integer)d;"));
+        assertEquals(0, exec("def d = (byte)0; Integer b = (Integer)d; b"));
+        assertEquals(0, exec("def d = (short)0; Integer b = (Integer)d; b"));
+        assertEquals(0, exec("def d = (char)0; Integer b = (Integer)d; b"));
+        assertEquals(0, exec("def d = 0; Integer b = (Integer)d; b"));
+        assertEquals(0, exec("def d = (long)0; Integer b = (Integer)d; b"));
+        assertEquals(0, exec("def d = (float)0; Integer b = (Integer)d; b"));
+        assertEquals(0, exec("def d = (double)0; Integer b = (Integer)d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Boolean.valueOf(true); Integer b = d;"));
+        assertEquals(0, exec("def d = Byte.valueOf(0); Integer b = (Integer)d; b"));
+        assertEquals(0, exec("def d = Short.valueOf(0); Integer b = (Integer)d; b"));
+        assertEquals(0, exec("def d = Character.valueOf(0); Integer b = (Integer)d; b"));
+        assertEquals(0, exec("def d = Integer.valueOf(0); Integer b = (Integer)d; b"));
+        assertEquals(0, exec("def d = Long.valueOf(0); Integer b = (Integer)d; b"));
+        assertEquals(0, exec("def d = Float.valueOf(0); Integer b = (Integer)d; b"));
+        assertEquals(0, exec("def d = Double.valueOf(0); Integer b = (Integer)d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = new ArrayList(); Integer b = (Integer)d;"));
+    }
+
+    public void testdefToLongExplicit() {
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = 'string'; Long b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = true; Long b = (Long)d;"));
+        assertEquals((long)0, exec("def d = (byte)0; Long b = (Long)d; b"));
+        assertEquals((long)0, exec("def d = (short)0; Long b = (Long)d; b"));
+        assertEquals((long)0, exec("def d = (char)0; Long b = (Long)d; b"));
+        assertEquals((long)0, exec("def d = 0; Long b = (Long)d; b"));
+        assertEquals((long)0, exec("def d = (long)0; Long b = (Long)d; b"));
+        assertEquals((long)0, exec("def d = (float)0; Long b = (Long)d; b"));
+        assertEquals((long)0, exec("def d = (double)0; Long b = (Long)d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Boolean.valueOf(true); Long b = d;"));
+        assertEquals((long)0, exec("def d = Byte.valueOf(0); Long b = (Long)d; b"));
+        assertEquals((long)0, exec("def d = Short.valueOf(0); Long b = (Long)d; b"));
+        assertEquals((long)0, exec("def d = Character.valueOf(0); Long b = (Long)d; b"));
+        assertEquals((long)0, exec("def d = Integer.valueOf(0); Long b = (Long)d; b"));
+        assertEquals((long)0, exec("def d = Long.valueOf(0); Long b = (Long)d; b"));
+        assertEquals((long)0, exec("def d = Float.valueOf(0); Long b = (Long)d; b"));
+        assertEquals((long)0, exec("def d = Double.valueOf(0); Long b = (Long)d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = new ArrayList(); Long b = (Long)d;"));
+    }
+
+    public void testdefToFloatExplicit() {
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = 'string'; Float b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = true; Float b = (Float)d;"));
+        assertEquals((float)0, exec("def d = (byte)0; Float b = (Float)d; b"));
+        assertEquals((float)0, exec("def d = (short)0; Float b = (Float)d; b"));
+        assertEquals((float)0, exec("def d = (char)0; Float b = (Float)d; b"));
+        assertEquals((float)0, exec("def d = 0; Float b = (Float)d; b"));
+        assertEquals((float)0, exec("def d = (long)0; Float b = (Float)d; b"));
+        assertEquals((float)0, exec("def d = (float)0; Float b = (Float)d; b"));
+        assertEquals((float)0, exec("def d = (double)0; Float b = (Float)d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Boolean.valueOf(true); Float b = d;"));
+        assertEquals((float)0, exec("def d = Byte.valueOf(0); Float b = (Float)d; b"));
+        assertEquals((float)0, exec("def d = Short.valueOf(0); Float b = (Float)d; b"));
+        assertEquals((float)0, exec("def d = Character.valueOf(0); Float b = (Float)d; b"));
+        assertEquals((float)0, exec("def d = Integer.valueOf(0); Float b = (Float)d; b"));
+        assertEquals((float)0, exec("def d = Long.valueOf(0); Float b = (Float)d; b"));
+        assertEquals((float)0, exec("def d = Float.valueOf(0); Float b = (Float)d; b"));
+        assertEquals((float)0, exec("def d = Double.valueOf(0); Float b = (Float)d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = new ArrayList(); Float b = (Float)d;"));
+    }
+
+    public void testdefToDoubleExplicit() {
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = 'string'; Double b = d;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = true; Double b = (Double)d;"));
+        assertEquals((double)0, exec("def d = (byte)0; Double b = (Double)d; b"));
+        assertEquals((double)0, exec("def d = (short)0; Double b = (Double)d; b"));
+        assertEquals((double)0, exec("def d = (char)0; Double b = (Double)d; b"));
+        assertEquals((double)0, exec("def d = 0; Double b = (Double)d; b"));
+        assertEquals((double)0, exec("def d = (long)0; Double b = (Double)d; b"));
+        assertEquals((double)0, exec("def d = (float)0; Double b = (Double)d; b"));
+        assertEquals((double)0, exec("def d = (double)0; Double b = (Double)d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = Boolean.valueOf(true); Double b = d;"));
+        assertEquals((double)0, exec("def d = Byte.valueOf(0); Double b = (Double)d; b"));
+        assertEquals((double)0, exec("def d = Short.valueOf(0); Double b = (Double)d; b"));
+        assertEquals((double)0, exec("def d = Character.valueOf(0); Double b = (Double)d; b"));
+        assertEquals((double)0, exec("def d = Integer.valueOf(0); Double b = (Double)d; b"));
+        assertEquals((double)0, exec("def d = Long.valueOf(0); Double b = (Double)d; b"));
+        assertEquals((double)0, exec("def d = Float.valueOf(0); Double b = (Double)d; b"));
+        assertEquals((double)0, exec("def d = Double.valueOf(0); Double b = (Double)d; b"));
+        expectScriptThrows(ClassCastException.class, () -> exec("def d = new ArrayList(); Double b = (Double)d;"));
+    }
 }