Index: ParameterizedGenericMethodBinding.java
===================================================================
RCS file: /home/eclipse/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/ParameterizedGenericMethodBinding.java,v
retrieving revision 1.37
diff -u -r1.37 ParameterizedGenericMethodBinding.java
--- ParameterizedGenericMethodBinding.java	10 Jun 2005 07:30:26 -0000	1.37
+++ ParameterizedGenericMethodBinding.java	20 Jun 2005 11:56:47 -0000
@@ -68,31 +68,13 @@
 			// 15.12.2.8 - inferring unresolved type arguments
 			if (hasUnresolvedTypeArgument(substitutes)) {
 				TypeBinding expectedType = null;
-				// if message invocation has expected type
-				if (invocationSite instanceof MessageSend) {
-					MessageSend message = (MessageSend) invocationSite;
-					expectedType = message.expectedType;
-				}
-				TypeBinding upperBound;
-				TypeBinding substitutedReturnType = methodSubstitute.returnType;
-				switch (substitutedReturnType.kind()) {
-					case Binding.TYPE_PARAMETER :
-						// should be: if no expected type, then assume Object
-						// actually it rather seems to handle the returned variable case by expecting its erasure instead
-						upperBound = Scope.substitute(methodSubstitute, ((TypeVariableBinding)substitutedReturnType).upperBound());
-						break;
-					case Binding.BASE_TYPE :
-						if (substitutedReturnType == VoidBinding) {
-							upperBound = null;
-							break;
-						}
-						// fallthrough
-					default:
-						upperBound = scope.getJavaLangObject(); 
-				}
-				// Object o = foo(); // where <T extends Serializable> T foo();
-				if (expectedType == null || (upperBound != null && upperBound.isCompatibleWith(expectedType))) {
-					expectedType = upperBound;
+				if (methodSubstitute.returnType != VoidBinding) {
+					// if message invocation has expected type
+					if (invocationSite instanceof MessageSend) {
+						MessageSend message = (MessageSend) invocationSite;
+						expectedType = message.expectedType;
+					}
+					if (expectedType == null) expectedType = scope.getJavaLangObject(); // assume Object by default
 				}
 				methodSubstitute = methodSubstitute.inferFromExpectedType(scope, expectedType, collectedSubstitutes, substitutes);
 				if (methodSubstitute == null) 
@@ -208,6 +190,7 @@
 						for (int j = 0, equalLength = equalSubstitutes.length; j < equalLength; j++) {
 							TypeBinding equalSubstitute = equalSubstitutes[j];
 							if (equalSubstitute == null) continue nextConstraint;
+//							if (equalSubstitute == current) continue nextConstraint;
 							if (equalSubstitute == current) {
 								// try to find a better different match if any in subsequent equal candidates
 								for (int k = j+1; k < equalLength; k++) {
@@ -387,19 +370,28 @@
 		computeSubstitutes: {
 		    // infer from expected return type
 			if (expectedType != null) {
-			    returnType.collectSubstitutes(scope, expectedType, collectedSubstitutes, CONSTRAINT_SUPER);
+			    this.returnType.collectSubstitutes(scope, expectedType, collectedSubstitutes, CONSTRAINT_SUPER);
 			}
 		    // infer from bounds of type parameters
 			for (int i = 0; i < varLength; i++) {
 				TypeVariableBinding originalVariable = originalVariables[i];
 				TypeBinding argument = this.typeArguments[i];
+				boolean argAlreadyInferred = argument != originalVariable;
 				if (originalVariable.firstBound == originalVariable.superclass) {
-					Scope.substitute(this, originalVariable.firstBound) // substitue original bound with resolved variables
-						.collectSubstitutes(scope, argument, collectedSubstitutes, CONSTRAINT_EXTENDS);
+					TypeBinding substitutedBound = Scope.substitute(this, originalVariable.superclass);
+					argument.collectSubstitutes(scope, substitutedBound, collectedSubstitutes, CONSTRAINT_SUPER);
+					// JLS 15.12.2.8 claims reverse inference shouldn't occur, however it improves inference
+					// e.g. given: <E extends Object, S extends Collection<E>> S test1(S param)
+					//                   invocation: test1(new Vector<String>())    will infer: S=Vector<String>  and with code below: E=String
+					if (argAlreadyInferred)
+						substitutedBound.collectSubstitutes(scope, argument, collectedSubstitutes, CONSTRAINT_EXTENDS);
 				}
 				for (int j = 0, max = originalVariable.superInterfaces.length; j < max; j++) {
-					Scope.substitute(this, originalVariable.superInterfaces[j]) // substitue original bound with resolved variables
-						.collectSubstitutes(scope, argument, collectedSubstitutes, CONSTRAINT_EXTENDS);
+					TypeBinding substitutedBound = Scope.substitute(this, originalVariable.superInterfaces[j]);
+					argument.collectSubstitutes(scope, substitutedBound, collectedSubstitutes, CONSTRAINT_SUPER);
+					// JLS 15.12.2.8 claims reverse inference shouldn't occur, however it improves inference
+					if (argAlreadyInferred)
+						substitutedBound.collectSubstitutes(scope, argument, collectedSubstitutes, CONSTRAINT_EXTENDS);
 				}
 			}
 			substitutes = resolveSubstituteConstraints(scope, originalVariables, substitutes, true/*consider Ti<:Uk*/, collectedSubstitutes);