KT-2701 Prevent redeclaration in multi-declaration

#KT-2701 Fixed

compiler/frontend/src/org/jetbrains/jet/lang/types/expressions/ExpressionTypingUtils.java

@@ -18,6 +18,7 @@ package org.jetbrains.jet.lang.types.expressions;
 
 import com.intellij.openapi.project.Project;
 import com.intellij.openapi.util.Pair;
+import com.intellij.psi.PsiElement;
 import com.intellij.psi.tree.IElementType;
 import com.intellij.psi.tree.TokenSet;
 import org.jetbrains.annotations.NotNull;
@@ -25,6 +26,7 @@ import org.jetbrains.annotations.Nullable;
 import org.jetbrains.jet.JetNodeTypes;
 import org.jetbrains.jet.lang.ModuleConfiguration;
 import org.jetbrains.jet.lang.descriptors.*;
+import org.jetbrains.jet.lang.diagnostics.Errors;
 import org.jetbrains.jet.lang.psi.*;
 import org.jetbrains.jet.lang.resolve.*;
 import org.jetbrains.jet.lang.resolve.calls.CallMaker;
@@ -341,10 +343,22 @@ public class ExpressionTypingUtils {
             VariableDescriptor variableDescriptor = context.expressionTypingServices.getDescriptorResolver().
                 resolveLocalVariableDescriptorWithType(writableScope.getContainingDeclaration(), entry, componentType, context.trace);
 
+            VariableDescriptor olderVariable = writableScope.getLocalVariable(variableDescriptor.getName());
+            checkVariableShadowing(context, variableDescriptor, olderVariable);
+
             writableScope.addVariableDescriptor(variableDescriptor);
         }
     }
 
+    public static void checkVariableShadowing(@NotNull ExpressionTypingContext context, @NotNull VariableDescriptor variableDescriptor, VariableDescriptor oldDescriptor) {
+        if (oldDescriptor != null && DescriptorUtils.isLocal(variableDescriptor.getContainingDeclaration(), oldDescriptor)) {
+            PsiElement declaration = BindingContextUtils.descriptorToDeclaration(context.trace.getBindingContext(), variableDescriptor);
+            if (declaration != null) {
+                context.trace.report(Errors.NAME_SHADOWING.on(declaration, variableDescriptor.getName().getName()));
+            }
+        }
+    }
+
     @NotNull
     private static JetType getExpectedTypeForComponent(ExpressionTypingContext context, JetMultiDeclarationEntry entry) {
         JetTypeReference entryTypeRef = entry.getTypeRef();

compiler/frontend/src/org/jetbrains/jet/lang/types/expressions/ExpressionTypingVisitorForStatements.java

@@ -117,10 +117,7 @@ public class ExpressionTypingVisitorForStatements extends ExpressionTypingVisito
         
         {
             VariableDescriptor olderVariable = scope.getLocalVariable(propertyDescriptor.getName());
-            if (olderVariable != null && DescriptorUtils.isLocal(propertyDescriptor.getContainingDeclaration(), olderVariable)) {
+            ExpressionTypingUtils.checkVariableShadowing(context, propertyDescriptor, olderVariable);
-                PsiElement declaration = BindingContextUtils.descriptorToDeclaration(context.trace.getBindingContext(), propertyDescriptor);
-                context.trace.report(Errors.NAME_SHADOWING.on(declaration, propertyDescriptor.getName().getName()));
-            }
         }
 
         scope.addVariableDescriptor(propertyDescriptor);

compiler/testData/diagnostics/tests/declarationChecks/RedeclarationsInMultiDecl.kt

@@ -4,11 +4,11 @@ class A {
 }
 
 fun a() {
-    val (<!REDECLARATION, UNUSED_VARIABLE!>a<!>, <!REDECLARATION, UNUSED_VARIABLE!>a<!>) = A()
+    val (<!REDECLARATION, UNUSED_VARIABLE!>a<!>, <!NAME_SHADOWING, REDECLARATION, UNUSED_VARIABLE!>a<!>) = A()
     val (<!UNUSED_VARIABLE!>x<!>, <!REDECLARATION, UNUSED_VARIABLE!>y<!>) = A();
     val <!REDECLARATION!>b<!> = 1
     use(b)
-    val (<!REDECLARATION, UNUSED_VARIABLE!>b<!>, <!REDECLARATION, UNUSED_VARIABLE!>y<!>) = A();
+    val (<!NAME_SHADOWING, REDECLARATION, UNUSED_VARIABLE!>b<!>, <!NAME_SHADOWING, REDECLARATION, UNUSED_VARIABLE!>y<!>) = A();
 }
 
 

compiler/testData/diagnostics/tests/declarationChecks/multiDeclarations/RedeclarationInForLoop.kt

@@ -8,7 +8,7 @@ class C {
 }
 
 fun test() {
-    for ((<!REDECLARATION!>x<!>, <!REDECLARATION!>x<!>) in C()) {
+    for ((<!REDECLARATION!>x<!>, <!NAME_SHADOWING, REDECLARATION!>x<!>) in C()) {
 
     }
 }

compiler/testData/diagnostics/tests/shadowing/ShadowMultiDeclarationWithFunParameter.kt

@@ -0,0 +1,14 @@
+class A {
+    fun component1() = 42
+    fun component2() = 42
+}
+
+fun foo(a: A, c: Int) {
+    val (<!NAME_SHADOWING!>a<!>, b) = a
+    val arr = Array(2) { A() }
+    for ((<!NAME_SHADOWING!>c<!>, d) in arr)  {
+        
+    }
+
+    val <!UNUSED_VARIABLE!>e<!> = a.toString() + b + c
+}

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

@@ -3386,6 +3386,11 @@ public class JetDiagnosticsTestGenerated extends AbstractDiagnosticsTestWithEage
                 JetTestUtils.assertAllTestsPresentByMetadata(this.getClass(), "org.jetbrains.jet.checkers.AbstractDiagnosticsTestWithEagerResolve", new File("compiler/testData/diagnostics/tests/shadowing"), "kt", true);
             }
             
+            @TestMetadata("ShadowMultiDeclarationWithFunParameter.kt")
+            public void testShadowMultiDeclarationWithFunParameter() throws Exception {
+                doTest("compiler/testData/diagnostics/tests/shadowing/ShadowMultiDeclarationWithFunParameter.kt");
+            }
+            
             @TestMetadata("ShadowParameterInFunctionBody.kt")
             public void testShadowParameterInFunctionBody() throws Exception {
                 doTest("compiler/testData/diagnostics/tests/shadowing/ShadowParameterInFunctionBody.kt");