*** empty log message ***

git-svn-id: http://lampsvn.epfl.ch/svn-repos/scala/scala/trunk@379 5e8d7ff9-d8ef-0310-90f0-a4852d11357a

sources/scalac/symtab/Symbol.java

@@ -156,7 +156,8 @@ public abstract class Symbol implements Modifiers, Kinds {
     public final boolean isStable() {
 	return kind == VAL && 
 	    ((flags & STABLE) != 0 ||
-	     (flags & MUTABLE) == 0 && type().isObjectType());
+	     (flags & MUTABLE) == 0 && type().isObjectType()) &&
+	    !owner.isPrimaryConstructor();
     }
 
     /** Does this symbol denote a variable? */

sources/scalac/symtab/Type.java

@@ -136,13 +136,27 @@ public class Type implements Modifiers, Kinds, TypeTags {
 	ExtSingleType(Type pre, Symbol sym) {
 	    super(pre, sym);
 	}
-	public Type widen() {
+	private Type type() {
 	    if (definedId != Global.instance.currentPhase.id) {
 		definedId = Global.instance.currentPhase.id;
-		tp = pre.memberType(sym).resultType().widen();
+		tp = pre.memberType(sym).resultType();
 	    }
 	    return tp;
 	}
+	/** If this type is a thistype or singleton type, its underlying object type,
+	 *  otherwise the type itself.
+	 */
+	public Type widen() {
+	    return type().widen();
+	}
+	/** If this type is a singleton type whose type is another, the end of the chain,
+	 *  otherwise the type itself.
+	 */
+	public Type aliasedType() {
+	    Type tp = type();
+	    if (tp.isStable()) return tp.aliasedType();
+	    else return this;
+	}
     }
 
     static class ExtCompoundType extends CompoundType {
@@ -222,6 +236,13 @@ public class Type implements Modifiers, Kinds, TypeTags {
 	return tps1;
     }
 
+    /** If this type is a singleton type whose type is another, the end of the chain,
+     *  otherwise the type itself.
+     */
+    public Type aliasedType() {
+	return this;
+    }
+
     /** The thistype or singleton type corresponding to values of this type.
       */
     public Type narrow() {
@@ -1197,25 +1218,12 @@ public class Type implements Modifiers, Kinds, TypeTags {
 	case NoType:
 	    return false;
 
-	case ThisType(Symbol sym1):
+	case ThisType(_):
+	case SingleType(_, _):
 	    switch (this) {
-	    case ThisType(Symbol sym):
-		return sym == sym1;
-	    case SingleType(Type pre, Symbol sym):
-		return sym.isModule() 
-		    && sym.moduleClass() == sym1
-		    && pre.isSameAs(sym1.owner().thisType());
-	    }
-	    break;
-
-	case SingleType(Type pre1, Symbol sym1):
-	    switch (this) {
-	    case SingleType(Type pre, Symbol sym):
-		return sym == sym1 && pre.isSameAs(pre1);
-	    case ThisType(Symbol sym):
-		return sym1.isModule() 
-		    && sym == sym1.moduleClass()
-		    && sym.owner().thisType().isSameAs(pre1);
+	    case ThisType(_):
+	    case SingleType(_, _):
+		return this.isSameAs(that);
 	    }
 	    break;
 
@@ -1445,20 +1453,27 @@ public class Type implements Modifiers, Kinds, TypeTags {
 	    case SingleType(Type pre1, Symbol sym1):
 		return sym1.isModule() 
 		    && sym == sym1.moduleClass()
-		    && sym.owner().thisType().isSameAs(pre1);
+		    && sym.owner().thisType().isSameAs(pre1)
+		    ||
+		    that != that.aliasedType() &&
+		    this.isSameAs(that.aliasedType());
 	    }
 	    break;
 
 	case SingleType(Type pre, Symbol sym):
 	    switch (that) {
 	    case SingleType(Type pre1, Symbol sym1):
-		return sym == sym1 && pre.isSameAs(pre1);
-		//|| sym.type.isStable() && sym.type.isSameAs(that)
-		//|| sym1.type.isStable() && this.isSameAs(sym1.type);
+		return sym == sym1 && pre.isSameAs(pre1)
+		    ||
+		    (this != this.aliasedType() || that != that.aliasedType()) &&
+		    this.aliasedType().isSameAs(that.aliasedType());
 	    case ThisType(Symbol sym1):
 		return sym.isModule() 
 		    && sym.moduleClass() == sym1
-		    && pre.isSameAs(sym1.owner().thisType());
+		    && pre.isSameAs(sym1.owner().thisType())
+		    ||
+		    this != this.aliasedType() &&
+		    this.aliasedType().isSameAs(that);
 	    }
 	    break;
 

sources/scalac/typechecker/Analyzer.java

@@ -527,8 +527,8 @@ public class Analyzer extends Transformer implements Modifiers, Kinds {
      */
     Tree checkStable(Tree tree) {
 	if (TreeInfo.isPureExpr(tree) || tree.type == Type.ErrorType) return tree;
-	new TextTreePrinter().print(tree).end();//debug
-	System.out.println(" " + tree.type);//debug
+	//new TextTreePrinter().print(tree).end();//DEBUG
+	//System.out.println(" " + tree.type);//DEBUG
 	return error(tree, "stable identifier required");
     }
 
@@ -822,8 +822,7 @@ public class Analyzer extends Transformer implements Modifiers, Kinds {
 		sym.constructor().flags |= INITIALIZED; 
 
 		if (tpe != Tree.Empty)
-		    sym.setTypeOfThis(
-			checkNoEscape(tpe.pos, transform(tpe, TYPEmode).type));
+		    sym.setTypeOfThis(transform(tpe, TYPEmode).type);
 
 		defineTemplate(templ, sym);
 		owntype = templ.type;
@@ -1664,8 +1663,6 @@ public class Analyzer extends Transformer implements Modifiers, Kinds {
 		Tree.ValDef[][] vparams1 = transform(vparams);
 		Tree tpe1 = transform(tpe);
 		Tree.Template templ1 = transformTemplate(templ, sym);
-		for (int i = 0; i < templ1.parents.length; i++) 
-		    checkNoEscape(templ1.parents[i].pos, templ1.parents[i].type);
 
 		if ((sym.flags & ABSTRACTCLASS) == 0 &&
 		    !sym.type().isSubType(sym.typeOfThis()))
@@ -2025,7 +2022,7 @@ public class Analyzer extends Transformer implements Modifiers, Kinds {
 		return tree;
 
 	    case SingletonType(Tree ref):
-		Tree ref1 = transform(ref, EXPRmode, Type.AnyType);
+		Tree ref1 = transform(ref, EXPRmode | QUALmode, Type.AnyType);
 		return make.TypeTerm(tree.pos)
 		    .setType(checkObjectType(tree.pos, ref1.type.resultType()));
 

test/files/neg/constrparams.scala

@@ -0,0 +1,6 @@
+abstract class C(x: C) {
+  type t;
+  private val y: x.type = x; 
+  private val z: x.t = null; //error
+}
+

test/files/pos/aliases.scala

@@ -0,0 +1,21 @@
+abstract class C() {
+
+  type t <: C;
+
+  val x: t;
+  val y: x.type;
+  val z: x.type;
+
+  val xt: x.t;
+  val yt: y.t;
+  val zt: z.t;
+
+  def fx(a: x.t): Unit;
+  def fy(a: y.t): Unit;
+  def fz(a: z.t): Unit;
+
+  fx(xt); fx(yt); fx(zt);
+  fy(xt); fy(yt); fy(zt);
+  fz(xt); fz(yt); fz(zt);
+
+}

test/files/pos/null.scala

@@ -0,0 +1,3 @@
+module M {
+  val x: Boolean = null == null;
+}

test/neg/constrparams.scala

@@ -0,0 +1,6 @@
+abstract class C(x: C) {
+  type t;
+  private val y: x.type = x; 
+  private val z: x.t = null; //error
+}
+

test/pos/aliases.scala

@@ -0,0 +1,21 @@
+abstract class C() {
+
+  type t <: C;
+
+  val x: t;
+  val y: x.type;
+  val z: x.type;
+
+  val xt: x.t;
+  val yt: y.t;
+  val zt: z.t;
+
+  def fx(a: x.t): Unit;
+  def fy(a: y.t): Unit;
+  def fz(a: z.t): Unit;
+
+  fx(xt); fx(yt); fx(zt);
+  fy(xt); fy(yt); fy(zt);
+  fz(xt); fz(yt); fz(zt);
+
+}

test/pos/null.scala

@@ -0,0 +1,3 @@
+module M {
+  val x: Boolean = null == null;
+}