A massive organize imports and formatting of the sources using default Eclipse code...
[phpeclipse.git] / net.sourceforge.phpeclipse / src / net / sourceforge / phpdt / internal / compiler / ast / Assignment.java
index ba59094..297f4a0 100644 (file)
 /*******************************************************************************
- * Copyright (c) 2000, 2001, 2002 International Business Machines Corp. and others.
+ * Copyright (c) 2000, 2003 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials 
- * are made available under the terms of the Common Public License v0.5 
+ * are made available under the terms of the Common Public License v1.0
  * which accompanies this distribution, and is available at
- * http://www.eclipse.org/legal/cpl-v05.html
+ * http://www.eclipse.org/legal/cpl-v10.html
  * 
  * Contributors:
  *     IBM Corporation - initial API and implementation
- ******************************************************************************/
+ *     Genady Beriozkin - added support for reporting assignment with no effect
+ *******************************************************************************/
 package net.sourceforge.phpdt.internal.compiler.ast;
 
-import net.sourceforge.phpdt.internal.compiler.IAbstractSyntaxTreeVisitor;
-import net.sourceforge.phpdt.internal.compiler.codegen.CodeStream;
+import net.sourceforge.phpdt.internal.compiler.ASTVisitor;
 import net.sourceforge.phpdt.internal.compiler.flow.FlowContext;
 import net.sourceforge.phpdt.internal.compiler.flow.FlowInfo;
 import net.sourceforge.phpdt.internal.compiler.lookup.BaseTypeBinding;
+import net.sourceforge.phpdt.internal.compiler.lookup.Binding;
 import net.sourceforge.phpdt.internal.compiler.lookup.BlockScope;
 import net.sourceforge.phpdt.internal.compiler.lookup.TypeBinding;
 
 public class Assignment extends Expression {
 
-       public Reference lhs;
+       public Expression lhs;
+
        public Expression expression;
-       public TypeBinding lhsType;
-       
+
        public Assignment(Expression lhs, Expression expression, int sourceEnd) {
-               //lhs is always a reference by construction ,
-               //but is build as an expression ==> the checkcast cannot fail
+               // lhs is always a reference by construction ,
+               // but is build as an expression ==> the checkcast cannot fail
+
+               this.lhs = lhs;
+               lhs.bits |= IsStrictlyAssignedMASK; // tag lhs as assigned
 
-               this.lhs = (Reference) lhs;
                this.expression = expression;
 
                this.sourceStart = lhs.sourceStart;
                this.sourceEnd = sourceEnd;
        }
 
-       public FlowInfo analyseCode(
-               BlockScope currentScope,
-               FlowContext flowContext,
-               FlowInfo flowInfo) {
-               // record setting a variable: various scenarii are possible, setting an array reference, 
-               // a field reference, a blank final field reference, a field of an enclosing instance or 
+       public FlowInfo analyseCode(BlockScope currentScope,
+                       FlowContext flowContext, FlowInfo flowInfo) {
+               // record setting a variable: various scenarii are possible, setting an
+               // array reference,
+               // a field reference, a blank final field reference, a field of an
+               // enclosing instance or
                // just a local variable.
 
-               return lhs
-                       .analyseAssignment(currentScope, flowContext, flowInfo, this, false)
-                       .unconditionalInits();
+               return ((Reference) lhs).analyseAssignment(currentScope, flowContext,
+                               flowInfo, this, false).unconditionalInits();
        }
 
-       public void generateCode(
-               BlockScope currentScope,
-               CodeStream codeStream,
-               boolean valueRequired) {
+       void checkAssignmentEffect(BlockScope scope) {
 
-               // various scenarii are possible, setting an array reference, 
-               // a field reference, a blank final field reference, a field of an enclosing instance or 
-               // just a local variable.
+               Binding left = getDirectBinding(this.lhs);
+               if (left != null && left == getDirectBinding(this.expression)) {
+                       scope.problemReporter().assignmentHasNoEffect(this,
+                                       left.shortReadableName());
+                       this.bits |= IsAssignmentWithNoEffectMASK; // record assignment has
+                                                                                                               // no effect
+               }
+       }
+
+       // public void generateCode(
+       // BlockScope currentScope,
+       // CodeStream codeStream,
+       // boolean valueRequired) {
+       //
+       // // various scenarii are possible, setting an array reference,
+       // // a field reference, a blank final field reference, a field of an
+       // enclosing instance or
+       // // just a local variable.
+       //
+       // int pc = codeStream.position;
+       // if ((this.bits & IsAssignmentWithNoEffectMASK) != 0) {
+       // if (valueRequired) {
+       // this.expression.generateCode(currentScope, codeStream, true);
+       // }
+       // } else {
+       // ((Reference) lhs).generateAssignment(currentScope, codeStream, this,
+       // valueRequired);
+       // // variable may have been optimized out
+       // // the lhs is responsible to perform the implicitConversion generation
+       // for the assignment since optimized for unused local assignment.
+       // }
+       // codeStream.recordPositionsFrom(pc, this.sourceStart);
+       // }
+
+       Binding getDirectBinding(Expression someExpression) {
+               if (someExpression instanceof SingleNameReference) {
+                       return ((SingleNameReference) someExpression).binding;
+               } else if (someExpression instanceof FieldReference) {
+                       FieldReference fieldRef = (FieldReference) someExpression;
+                       if (fieldRef.receiver.isThis()
+                                       && !(fieldRef.receiver instanceof QualifiedThisReference)) {
+                               return fieldRef.binding;
+                       }
+               }
+               return null;
+       }
+
+       public StringBuffer print(int indent, StringBuffer output) {
+
+               // no () when used as a statement
+               printIndent(indent, output);
+               return printExpressionNoParenthesis(indent, output);
+       }
+
+       public StringBuffer printExpression(int indent, StringBuffer output) {
 
-               int pc = codeStream.position;
-               lhs.generateAssignment(currentScope, codeStream, this, valueRequired);
-               // variable may have been optimized out
-               // the lhs is responsible to perform the implicitConversion generation for the assignment since optimized for unused local assignment.
-               codeStream.recordPositionsFrom(pc, this.sourceStart);
+               // subclass redefine printExpressionNoParenthesis()
+               output.append('(');
+               return printExpressionNoParenthesis(0, output).append(')');
+       }
+
+       public StringBuffer printExpressionNoParenthesis(int indent,
+                       StringBuffer output) {
+
+               lhs.printExpression(indent, output).append(" = "); //$NON-NLS-1$
+               return expression.printExpression(0, output);
+       }
+
+       public StringBuffer printStatement(int indent, StringBuffer output) {
+
+               // no () when used as a statement
+               return print(indent, output).append(';');
        }
 
        public TypeBinding resolveType(BlockScope scope) {
 
-               // due to syntax lhs may be only a NameReference, a FieldReference or an ArrayReference
+               // due to syntax lhs may be only a NameReference, a FieldReference or an
+               // ArrayReference
                constant = NotAConstant;
-               this.lhsType = lhs.resolveType(scope);
-               TypeBinding expressionTb = expression.resolveType(scope);
-               if (this.lhsType == null || expressionTb == null)
+               if (!(this.lhs instanceof Reference)) {
+                       scope.problemReporter().expressionShouldBeAVariable(this.lhs);
+               }
+               this.resolvedType = lhs.resolveType(scope); // expressionType contains
+                                                                                                       // the assignment type (lhs
+                                                                                                       // Type)
+               TypeBinding rhsType = expression.resolveType(scope);
+               if (this.resolvedType == null || rhsType == null) {
                        return null;
+               }
+               checkAssignmentEffect(scope);
 
-               // Compile-time conversion of base-types : implicit narrowing integer into byte/short/character
+               // Compile-time conversion of base-types : implicit narrowing integer
+               // into byte/short/character
                // may require to widen the rhs expression at runtime
-               if ((expression.isConstantValueOfTypeAssignableToType(expressionTb, this.lhsType)
-                       || (this.lhsType.isBaseType() && BaseTypeBinding.isWidening(this.lhsType.id, expressionTb.id)))
-                       || (BlockScope.areTypesCompatible(expressionTb, this.lhsType))) {
-                       expression.implicitWidening(this.lhsType, expressionTb);
-                       return this.lhsType;
+               if ((expression.isConstantValueOfTypeAssignableToType(rhsType,
+                               this.resolvedType) || (this.resolvedType.isBaseType() && BaseTypeBinding
+                               .isWidening(this.resolvedType.id, rhsType.id)))
+                               || rhsType.isCompatibleWith(this.resolvedType)) {
+                       expression.implicitWidening(this.resolvedType, rhsType);
+                       return this.resolvedType;
                }
                scope.problemReporter().typeMismatchErrorActualTypeExpectedType(
-                       expression,
-                       expressionTb,
-                       this.lhsType);
-               return null;
+                               expression, rhsType, this.resolvedType);
+               return this.resolvedType;
        }
 
        public String toString(int tab) {
 
-               //no () when used as a statement 
+               // no () when used as a statement
                return tabString(tab) + toStringExpressionNoParenthesis();
        }
 
        public String toStringExpression() {
 
-               //subclass redefine toStringExpressionNoParenthesis()
+               // subclass redefine toStringExpressionNoParenthesis()
                return "(" + toStringExpressionNoParenthesis() + ")"; //$NON-NLS-2$ //$NON-NLS-1$
-       } 
-       
+       }
+
        public String toStringExpressionNoParenthesis() {
 
-               return lhs.toStringExpression() + " " //$NON-NLS-1$
-                       + "=" //$NON-NLS-1$
-                       + ((expression.constant != null) && (expression.constant != NotAConstant)
-                               ? " /*cst:" + expression.constant.toString() + "*/ " //$NON-NLS-1$ //$NON-NLS-2$
-                               : " ")  //$NON-NLS-1$
-                       + expression.toStringExpression();
+               return lhs.toStringExpression()
+                               + " " //$NON-NLS-1$
+                               + "=" //$NON-NLS-1$
+                               + ((expression.constant != null)
+                                               && (expression.constant != NotAConstant) ? " /*cst:" + expression.constant.toString() + "*/ " //$NON-NLS-1$ //$NON-NLS-2$
+                                               : " ") //$NON-NLS-1$
+                               + expression.toStringExpression();
        }
-       public void traverse(IAbstractSyntaxTreeVisitor visitor, BlockScope scope) {
-               
+
+       public void traverse(ASTVisitor visitor, BlockScope scope) {
+
                if (visitor.visit(this, scope)) {
                        lhs.traverse(visitor, scope);
                        expression.traverse(visitor, scope);