Tests for shadowing and redeclaration

idea/testData/checker/Redeclaration.kt

@@ -0,0 +1,28 @@
+val <error>a</error> : Int = 1
+val <error>a</error> : Int = 1
+
+<error>fun foo()</error> {}
+<error>fun foo()</error> {}
+
+enum class EnumClass {
+    <error>FOO</error>
+    <error>FOO</error>
+}
+
+class A {
+    val <error>a</error> : Int = 1
+    val <error>a</error> : Int = 1
+
+    <error>fun foo()</error> {}
+    <error>fun foo()</error> {}
+}
+
+object B {
+    class <error>C</error>
+    class <error>C</error>
+}
+
+fun PairParam<<error>T</error>, <error>T</error>>() {}
+class PParam<<error>T</error>, <error>T</error>> {}
+
+val <<error>T</error>, <error>T</error>> T.fooParam : Int = 1

idea/testData/checker/Shadowing.kt

@@ -0,0 +1,17 @@
+class A {
+    fun component1() = 42
+    fun component2() = 42
+}
+
+fun foo(a: A, <warning>c</warning>: Int) {
+    val (<warning descr="[NAME_SHADOWING] Name shadowed: a"><warning descr="[UNUSED_VARIABLE] Variable 'a' is never used">a</warning></warning>, <warning>b</warning>) = a
+    val arr = Array(2) { A() }
+    for ((<warning descr="[NAME_SHADOWING] Name shadowed: c">c</warning>, d) in arr) {
+    }
+}
+
+fun f(<warning>p</warning>: Int): Int {
+    val <error>p</error> = 2
+    val <error>p</error> = 3
+    return p
+}