Minor, explain why we don't store array type arguments in ::class in proto

build-common/test/org/jetbrains/kotlin/metadata/DebugProtoBuf.java

@@ -2643,7 +2643,9 @@ public final class DebugProtoBuf {
          * - Array<String>::class, if array_dimension_count = 1
          * - Array<Array<String>>::class, if array_dimension_count = 2
          * - etc.
-         * Other forms of array class literals are not supported by this format, see KT-26568
+         * Since it's very difficult to represent Kotlin-specific type aspects (nullability, type projections) of array arguments
+         * in class literals on JVM, we don't bother to do represent this in our format as well.
+         * So, for example, values `Array<Array<in B?>>::class` and `Array<out Array<B>>?>::class` will be represented exactly the same here.
          * </pre>
          */
         boolean hasArrayDimensionCount();
@@ -2657,7 +2659,9 @@ public final class DebugProtoBuf {
          * - Array&lt;String&gt;::class, if array_dimension_count = 1
          * - Array&lt;Array&lt;String&gt;&gt;::class, if array_dimension_count = 2
          * - etc.
-         * Other forms of array class literals are not supported by this format, see KT-26568
+         * Since it's very difficult to represent Kotlin-specific type aspects (nullability, type projections) of array arguments
+         * in class literals on JVM, we don't bother to do represent this in our format as well.
+         * So, for example, values `Array&lt;Array&lt;in B?&gt;&gt;::class` and `Array&lt;out Array&lt;B&gt;&gt;?&gt;::class` will be represented exactly the same here.
          * </pre>
          */
         int getArrayDimensionCount();
@@ -3220,7 +3224,9 @@ public final class DebugProtoBuf {
          * - Array&lt;String&gt;::class, if array_dimension_count = 1
          * - Array&lt;Array&lt;String&gt;&gt;::class, if array_dimension_count = 2
          * - etc.
-         * Other forms of array class literals are not supported by this format, see KT-26568
+         * Since it's very difficult to represent Kotlin-specific type aspects (nullability, type projections) of array arguments
+         * in class literals on JVM, we don't bother to do represent this in our format as well.
+         * So, for example, values `Array&lt;Array&lt;in B?&gt;&gt;::class` and `Array&lt;out Array&lt;B&gt;&gt;?&gt;::class` will be represented exactly the same here.
          * </pre>
          */
         public boolean hasArrayDimensionCount() {
@@ -3236,7 +3242,9 @@ public final class DebugProtoBuf {
          * - Array&lt;String&gt;::class, if array_dimension_count = 1
          * - Array&lt;Array&lt;String&gt;&gt;::class, if array_dimension_count = 2
          * - etc.
-         * Other forms of array class literals are not supported by this format, see KT-26568
+         * Since it's very difficult to represent Kotlin-specific type aspects (nullability, type projections) of array arguments
+         * in class literals on JVM, we don't bother to do represent this in our format as well.
+         * So, for example, values `Array&lt;Array&lt;in B?&gt;&gt;::class` and `Array&lt;out Array&lt;B&gt;&gt;?&gt;::class` will be represented exactly the same here.
          * </pre>
          */
         public int getArrayDimensionCount() {
@@ -4365,7 +4373,9 @@ public final class DebugProtoBuf {
            * - Array&lt;String&gt;::class, if array_dimension_count = 1
            * - Array&lt;Array&lt;String&gt;&gt;::class, if array_dimension_count = 2
            * - etc.
-           * Other forms of array class literals are not supported by this format, see KT-26568
+           * Since it's very difficult to represent Kotlin-specific type aspects (nullability, type projections) of array arguments
+           * in class literals on JVM, we don't bother to do represent this in our format as well.
+           * So, for example, values `Array&lt;Array&lt;in B?&gt;&gt;::class` and `Array&lt;out Array&lt;B&gt;&gt;?&gt;::class` will be represented exactly the same here.
            * </pre>
            */
           public boolean hasArrayDimensionCount() {
@@ -4381,7 +4391,9 @@ public final class DebugProtoBuf {
            * - Array&lt;String&gt;::class, if array_dimension_count = 1
            * - Array&lt;Array&lt;String&gt;&gt;::class, if array_dimension_count = 2
            * - etc.
-           * Other forms of array class literals are not supported by this format, see KT-26568
+           * Since it's very difficult to represent Kotlin-specific type aspects (nullability, type projections) of array arguments
+           * in class literals on JVM, we don't bother to do represent this in our format as well.
+           * So, for example, values `Array&lt;Array&lt;in B?&gt;&gt;::class` and `Array&lt;out Array&lt;B&gt;&gt;?&gt;::class` will be represented exactly the same here.
            * </pre>
            */
           public int getArrayDimensionCount() {
@@ -4397,7 +4409,9 @@ public final class DebugProtoBuf {
            * - Array&lt;String&gt;::class, if array_dimension_count = 1
            * - Array&lt;Array&lt;String&gt;&gt;::class, if array_dimension_count = 2
            * - etc.
-           * Other forms of array class literals are not supported by this format, see KT-26568
+           * Since it's very difficult to represent Kotlin-specific type aspects (nullability, type projections) of array arguments
+           * in class literals on JVM, we don't bother to do represent this in our format as well.
+           * So, for example, values `Array&lt;Array&lt;in B?&gt;&gt;::class` and `Array&lt;out Array&lt;B&gt;&gt;?&gt;::class` will be represented exactly the same here.
            * </pre>
            */
           public Builder setArrayDimensionCount(int value) {
@@ -4416,7 +4430,9 @@ public final class DebugProtoBuf {
            * - Array&lt;String&gt;::class, if array_dimension_count = 1
            * - Array&lt;Array&lt;String&gt;&gt;::class, if array_dimension_count = 2
            * - etc.
-           * Other forms of array class literals are not supported by this format, see KT-26568
+           * Since it's very difficult to represent Kotlin-specific type aspects (nullability, type projections) of array arguments
+           * in class literals on JVM, we don't bother to do represent this in our format as well.
+           * So, for example, values `Array&lt;Array&lt;in B?&gt;&gt;::class` and `Array&lt;out Array&lt;B&gt;&gt;?&gt;::class` will be represented exactly the same here.
            * </pre>
            */
           public Builder clearArrayDimensionCount() {

core/metadata/src/metadata.proto

@@ -90,7 +90,9 @@ message Annotation {
       // - Array<String>::class, if array_dimension_count = 1
       // - Array<Array<String>>::class, if array_dimension_count = 2
       // - etc.
-      // Other forms of array class literals are not supported by this format, see KT-26568
+      // Since it's very difficult to represent Kotlin-specific type aspects (nullability, type projections) of array arguments
+      // in class literals on JVM, we don't bother to do represent this in our format as well.
+      // So, for example, values `Array<Array<in B?>>::class` and `Array<out Array<B>>?>::class` will be represented exactly the same here.
       optional int32 array_dimension_count = 11 [default = 0];
 
       /*

core/metadata/src/org/jetbrains/kotlin/metadata/ProtoBuf.java

@@ -2211,7 +2211,9 @@ public final class ProtoBuf {
          * - Array<String>::class, if array_dimension_count = 1
          * - Array<Array<String>>::class, if array_dimension_count = 2
          * - etc.
-         * Other forms of array class literals are not supported by this format, see KT-26568
+         * Since it's very difficult to represent Kotlin-specific type aspects (nullability, type projections) of array arguments
+         * in class literals on JVM, we don't bother to do represent this in our format as well.
+         * So, for example, values `Array<Array<in B?>>::class` and `Array<out Array<B>>?>::class` will be represented exactly the same here.
          * </pre>
          */
         boolean hasArrayDimensionCount();
@@ -2225,7 +2227,9 @@ public final class ProtoBuf {
          * - Array&lt;String&gt;::class, if array_dimension_count = 1
          * - Array&lt;Array&lt;String&gt;&gt;::class, if array_dimension_count = 2
          * - etc.
-         * Other forms of array class literals are not supported by this format, see KT-26568
+         * Since it's very difficult to represent Kotlin-specific type aspects (nullability, type projections) of array arguments
+         * in class literals on JVM, we don't bother to do represent this in our format as well.
+         * So, for example, values `Array&lt;Array&lt;in B?&gt;&gt;::class` and `Array&lt;out Array&lt;B&gt;&gt;?&gt;::class` will be represented exactly the same here.
          * </pre>
          */
         int getArrayDimensionCount();
@@ -2749,7 +2753,9 @@ public final class ProtoBuf {
          * - Array&lt;String&gt;::class, if array_dimension_count = 1
          * - Array&lt;Array&lt;String&gt;&gt;::class, if array_dimension_count = 2
          * - etc.
-         * Other forms of array class literals are not supported by this format, see KT-26568
+         * Since it's very difficult to represent Kotlin-specific type aspects (nullability, type projections) of array arguments
+         * in class literals on JVM, we don't bother to do represent this in our format as well.
+         * So, for example, values `Array&lt;Array&lt;in B?&gt;&gt;::class` and `Array&lt;out Array&lt;B&gt;&gt;?&gt;::class` will be represented exactly the same here.
          * </pre>
          */
         public boolean hasArrayDimensionCount() {
@@ -2765,7 +2771,9 @@ public final class ProtoBuf {
          * - Array&lt;String&gt;::class, if array_dimension_count = 1
          * - Array&lt;Array&lt;String&gt;&gt;::class, if array_dimension_count = 2
          * - etc.
-         * Other forms of array class literals are not supported by this format, see KT-26568
+         * Since it's very difficult to represent Kotlin-specific type aspects (nullability, type projections) of array arguments
+         * in class literals on JVM, we don't bother to do represent this in our format as well.
+         * So, for example, values `Array&lt;Array&lt;in B?&gt;&gt;::class` and `Array&lt;out Array&lt;B&gt;&gt;?&gt;::class` will be represented exactly the same here.
          * </pre>
          */
         public int getArrayDimensionCount() {
@@ -3652,7 +3660,9 @@ public final class ProtoBuf {
            * - Array&lt;String&gt;::class, if array_dimension_count = 1
            * - Array&lt;Array&lt;String&gt;&gt;::class, if array_dimension_count = 2
            * - etc.
-           * Other forms of array class literals are not supported by this format, see KT-26568
+           * Since it's very difficult to represent Kotlin-specific type aspects (nullability, type projections) of array arguments
+           * in class literals on JVM, we don't bother to do represent this in our format as well.
+           * So, for example, values `Array&lt;Array&lt;in B?&gt;&gt;::class` and `Array&lt;out Array&lt;B&gt;&gt;?&gt;::class` will be represented exactly the same here.
            * </pre>
            */
           public boolean hasArrayDimensionCount() {
@@ -3668,7 +3678,9 @@ public final class ProtoBuf {
            * - Array&lt;String&gt;::class, if array_dimension_count = 1
            * - Array&lt;Array&lt;String&gt;&gt;::class, if array_dimension_count = 2
            * - etc.
-           * Other forms of array class literals are not supported by this format, see KT-26568
+           * Since it's very difficult to represent Kotlin-specific type aspects (nullability, type projections) of array arguments
+           * in class literals on JVM, we don't bother to do represent this in our format as well.
+           * So, for example, values `Array&lt;Array&lt;in B?&gt;&gt;::class` and `Array&lt;out Array&lt;B&gt;&gt;?&gt;::class` will be represented exactly the same here.
            * </pre>
            */
           public int getArrayDimensionCount() {
@@ -3684,7 +3696,9 @@ public final class ProtoBuf {
            * - Array&lt;String&gt;::class, if array_dimension_count = 1
            * - Array&lt;Array&lt;String&gt;&gt;::class, if array_dimension_count = 2
            * - etc.
-           * Other forms of array class literals are not supported by this format, see KT-26568
+           * Since it's very difficult to represent Kotlin-specific type aspects (nullability, type projections) of array arguments
+           * in class literals on JVM, we don't bother to do represent this in our format as well.
+           * So, for example, values `Array&lt;Array&lt;in B?&gt;&gt;::class` and `Array&lt;out Array&lt;B&gt;&gt;?&gt;::class` will be represented exactly the same here.
            * </pre>
            */
           public Builder setArrayDimensionCount(int value) {
@@ -3703,7 +3717,9 @@ public final class ProtoBuf {
            * - Array&lt;String&gt;::class, if array_dimension_count = 1
            * - Array&lt;Array&lt;String&gt;&gt;::class, if array_dimension_count = 2
            * - etc.
-           * Other forms of array class literals are not supported by this format, see KT-26568
+           * Since it's very difficult to represent Kotlin-specific type aspects (nullability, type projections) of array arguments
+           * in class literals on JVM, we don't bother to do represent this in our format as well.
+           * So, for example, values `Array&lt;Array&lt;in B?&gt;&gt;::class` and `Array&lt;out Array&lt;B&gt;&gt;?&gt;::class` will be represented exactly the same here.
            * </pre>
            */
           public Builder clearArrayDimensionCount() {