Unextend Char from Number

This is impossible to achieve on JVM, where java/lang/Character does not extend
java/lang/Number

compiler/frontend/builtins/jet/CharIterator.kotlin_class

@@ -1,9 +1,9 @@
-&!2
+&"2
 
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+&0MB
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compiler/frontend/builtins/jet/Number.kotlin_class

@@ -1,5 +1,5 @@
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+2
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compiler/frontend/builtins/jet/PropertyMetadata.kotlin_class

@@ -1,3 +1,3 @@
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compiler/frontend/builtins/jet/Throwable.kotlin_class

@@ -1,9 +1,9 @@
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compiler/testData/builtin-classes.txt

@@ -166,7 +166,7 @@ public final class ByteRange : jet.Range<jet.Byte>, jet.Progression<jet.Byte> {
     }
 }
 
-public final class Char : jet.Number, jet.Comparable<jet.Char> {
+public final class Char : jet.Hashable, jet.Comparable<jet.Char> {
     /*primary*/ private constructor Char()
     public final fun compareTo(/*0*/ other: jet.Byte): jet.Int
     public open override /*1*/ fun compareTo(/*0*/ other: jet.Char): jet.Int
@@ -213,13 +213,13 @@ public final class Char : jet.Number, jet.Comparable<jet.Char> {
     public final fun times(/*0*/ other: jet.Int): jet.Int
     public final fun times(/*0*/ other: jet.Long): jet.Long
     public final fun times(/*0*/ other: jet.Short): jet.Int
-    public open override /*1*/ fun toByte(): jet.Byte
-    public open override /*1*/ fun toChar(): jet.Char
-    public open override /*1*/ fun toDouble(): jet.Double
-    public open override /*1*/ fun toFloat(): jet.Float
-    public open override /*1*/ fun toInt(): jet.Int
-    public open override /*1*/ fun toLong(): jet.Long
-    public open override /*1*/ fun toShort(): jet.Short
+    public open fun toByte(): jet.Byte
+    public open fun toChar(): jet.Char
+    public open fun toDouble(): jet.Double
+    public open fun toFloat(): jet.Float
+    public open fun toInt(): jet.Int
+    public open fun toLong(): jet.Long
+    public open fun toShort(): jet.Short
 }
 
 public final class CharArray {

compiler/testData/diagnostics/tests/numbers/characterIsNotANumber.kt

@@ -0,0 +1,11 @@
+fun foo(n: Number) = n
+
+fun test() {
+    foo(<!CONSTANT_EXPECTED_TYPE_MISMATCH!>'a'<!>)
+    
+    val c = 'c'
+    foo(<!TYPE_MISMATCH!>c<!>)
+
+    val d: Char? = 'd'
+    foo(<!TYPE_MISMATCH!>d<!>!!)
+}

compiler/tests/org/jetbrains/jet/checkers/JetDiagnosticsTestGenerated.java

@@ -4620,6 +4620,11 @@ public class JetDiagnosticsTestGenerated extends AbstractDiagnosticsTestWithEage
                 JetTestUtils.assertAllTestsPresentByMetadata(this.getClass(), "org.jetbrains.jet.generators.tests.GenerateTests", new File("compiler/testData/diagnostics/tests/numbers"), Pattern.compile("^(.+)\\.kt$"), true);
             }
             
+            @TestMetadata("characterIsNotANumber.kt")
+            public void testCharacterIsNotANumber() throws Exception {
+                doTest("compiler/testData/diagnostics/tests/numbers/characterIsNotANumber.kt");
+            }
+            
             @TestMetadata("doublesInSimpleConstraints.kt")
             public void testDoublesInSimpleConstraints() throws Exception {
                 doTest("compiler/testData/diagnostics/tests/numbers/doublesInSimpleConstraints.kt");

idea/builtinsSrc/jet/Numbers.kt

@@ -328,7 +328,7 @@ public class Int private () : Number, Comparable<Int> {
   public override fun equals(other : Any?) : Boolean
 }
 
-public class Char private () : Number, Comparable<Char> {
+public class Char private () : Hashable, Comparable<Char> {
   public fun compareTo(other : Double) : Int
   public fun compareTo(other : Float)  : Int
   public fun compareTo(other : Long)    : Int
@@ -384,13 +384,13 @@ public class Char private () : Number, Comparable<Char> {
   public fun plus() : Int
   public fun minus() : Int
 
-  public override fun toDouble() : Double
-  public override fun toFloat() : Float
-  public override fun toLong() : Long
-  public override fun toInt() : Int
-  public override fun toChar() : Char
-  public override fun toShort() : Short
-  public override fun toByte() : Byte
+  public fun toDouble() : Double
+  public fun toFloat() : Float
+  public fun toLong() : Long
+  public fun toInt() : Int
+  public fun toChar() : Char
+  public fun toShort() : Short
+  public fun toByte() : Byte
 
   public override fun hashCode() : Int
   public override fun equals(other : Any?) : Boolean