KT-2632 Check multi-declaraions in for-loops

#KT-2632 Fixed

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

@@ -0,0 +1,14 @@
+class A {
+    fun component1() = 1
+    fun component2() = 1
+}
+
+class C {
+    fun iterator(): Iterator<A> = null!!
+}
+
+fun test() {
+    for ((x, y) in C()) {
+
+    }
+}

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

@@ -0,0 +1,14 @@
+class A {
+    fun component1() = 1
+    fun component2() = 1.0
+}
+
+class C {
+    fun iterator(): Iterator<A> = null!!
+}
+
+fun test() {
+    for ((x: Double, y: Int) in <!COMPONENT_FUNCTION_RETURN_TYPE_MISMATCH, COMPONENT_FUNCTION_RETURN_TYPE_MISMATCH!>C()<!>) {
+
+    }
+}

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

@@ -0,0 +1,15 @@
+class A {
+    <!CONFLICTING_OVERLOADS!>fun component1()<!> = 1
+    <!CONFLICTING_OVERLOADS!>fun component1()<!> = 1
+    fun component2() = 1
+}
+
+class C {
+    fun iterator(): Iterator<A> = null!!
+}
+
+fun test() {
+    for ((x, y) in <!COMPONENT_FUNCTION_AMBIGUITY!>C()<!>) {
+
+    }
+}

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

@@ -0,0 +1,13 @@
+class A {
+    fun component1() = 1
+}
+
+class C {
+    fun iterator(): Iterator<A> = null!!
+}
+
+fun test() {
+    for ((x, y) in <!COMPONENT_FUNCTION_MISSING!>C()<!>) {
+
+    }
+}

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

@@ -0,0 +1,14 @@
+class A {
+}
+fun A.component1() = 1
+fun A.component2() = 1
+
+class C {
+    fun iterator(): Iterator<A> = null!!
+}
+
+fun test() {
+    for ((x, y) in C()) {
+
+    }
+}

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

@@ -0,0 +1,14 @@
+class A {
+    fun component1() = 1
+    fun component2() = 1.0
+}
+
+class C {
+    fun iterator(): Iterator<A> = null!!
+}
+
+fun test() {
+    for ((x: Int, y: Double) in C()) {
+
+    }
+}

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

@@ -0,0 +1,14 @@
+class A {
+    fun component1() = 1
+    fun component2() = 1
+}
+
+class C {
+    fun iterator(): Iterator<A> = null!!
+}
+
+fun test() {
+    for ((<!REDECLARATION!>x<!>, <!REDECLARATION!>x<!>) in C()) {
+
+    }
+}

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

@@ -0,0 +1,13 @@
+class A {
+    fun component1() = 1
+}
+
+class C {
+    fun iterator(): Iterator<A> = null!!
+}
+
+fun test() {
+    for ((x) in C()) {
+
+    }
+}