Report diagnostic on import with explicit import class if class was imported earlier.

compiler/testData/diagnostics/tests/imports/ClassImportsConflicting.kt

@@ -1,8 +1,8 @@
 //FILE:a.kt
 package a
 
-import <!CONFLICTING_IMPORT!>b.O<!>
-import <!CONFLICTING_IMPORT!>c.O<!>
+import b.<!CONFLICTING_IMPORT!>O<!>
+import c.<!CONFLICTING_IMPORT!>O<!>
 
 //FILE:b.kt
 package b
@@ -12,4 +12,4 @@ object O {}
 //FILE:c.kt
 package c
 
-object O {}
+object O {}

compiler/testData/diagnostics/tests/imports/ExplicitImportsAmbiguity.kt

@@ -11,7 +11,7 @@ class X
 // FILE: c.kt
 package c
 
-import <!CONFLICTING_IMPORT!>a.X<!>
-import <!CONFLICTING_IMPORT!>b.X<!>
+import a.<!CONFLICTING_IMPORT!>X<!>
+import b.<!CONFLICTING_IMPORT!>X<!>
 
 class Y : <!UNRESOLVED_REFERENCE!>X<!>

compiler/testData/diagnostics/tests/imports/ImportClassClash.kt

@@ -0,0 +1,48 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+// FILE: 1.kt
+package a
+
+class someFun() {}
+fun someFun(i: Int) {}
+
+class someVal() {}
+val Int.someVal: Int get() = 3
+
+class A
+
+class B
+
+// FILE: 2.kt
+package b
+
+class someFun
+class someVal
+class someAll
+
+fun A() {}
+
+class B
+
+
+// FILE: 3.kt
+import a.<!CONFLICTING_IMPORT!>someFun<!>
+import b.<!CONFLICTING_IMPORT!>someFun<!>
+
+import a.<!CONFLICTING_IMPORT!>someVal<!>
+import b.<!CONFLICTING_IMPORT!>someVal<!>
+
+import a.A
+import b.A
+
+// FILE: 4.kt
+import b.*
+import a.B
+
+// FILE: 5.kt
+package b
+
+import a.B
+
+// FILE: 6.kt
+import a.<!CONFLICTING_IMPORT!>B<!>
+import b.<!CONFLICTING_IMPORT!>B<!>

compiler/testData/diagnostics/tests/imports/ImportClassClash.txt

@@ -0,0 +1,66 @@
+package
+
+package a {
+    public val kotlin.Int.someVal: kotlin.Int
+    public fun someFun(/*0*/ i: kotlin.Int): kotlin.Unit
+
+    public final class A {
+        public constructor A()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public final class B {
+        public constructor B()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public final class someFun {
+        public constructor someFun()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public final class someVal {
+        public constructor someVal()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+package b {
+    public fun A(): kotlin.Unit
+
+    public final class B {
+        public constructor B()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public final class someAll {
+        public constructor someAll()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public final class someFun {
+        public constructor someFun()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public final class someVal {
+        public constructor someVal()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}

compiler/testData/diagnostics/tests/imports/NestedClassClash.kt

@@ -14,8 +14,8 @@ class D {
 }
 
 // FILE: c.kt
-import <!CONFLICTING_IMPORT!>a.A.B<!>
-import <!CONFLICTING_IMPORT!>a.D.B<!>
+import a.A.<!CONFLICTING_IMPORT!>B<!>
+import a.D.<!CONFLICTING_IMPORT!>B<!>
 
 fun test(b: <!UNRESOLVED_REFERENCE!>B<!>) {
     <!UNRESOLVED_REFERENCE!>B<!>()