Discriminate 'platform' declarations in resolution

Otherwise calls to functions which are declared twice (platform and impl) would
result in an error "conflicting overloads" in platform-specific modules

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/results/FlatSignatureForResolvedCall.kt

@@ -17,6 +17,7 @@
 package org.jetbrains.kotlin.resolve.calls.results
 
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
+import org.jetbrains.kotlin.descriptors.MemberDescriptor
 import org.jetbrains.kotlin.psi.ValueArgument
 import org.jetbrains.kotlin.resolve.DescriptorToSourceUtils
 import org.jetbrains.kotlin.resolve.calls.inference.ConstraintSystemBuilderImpl
@@ -55,7 +56,8 @@ fun <RC : ResolvedCall<*>> RC.createFlatSignature(): FlatSignature<RC> {
                                                call.valueArguments.map { valueArgumentToParameterType[it] },
                          hasExtensionReceiver = originalDescriptor.extensionReceiverParameter != null,
                          hasVarargs = originalDescriptor.valueParameters.any { it.varargElementType != null },
-                         numDefaults = numDefaults)
+                         numDefaults = numDefaults,
+                         isPlatform = originalDescriptor is MemberDescriptor && originalDescriptor.isPlatform)
 }
 
 fun createOverloadingConflictResolver(

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/results/FlatSignature.kt

@@ -17,6 +17,7 @@
 package org.jetbrains.kotlin.resolve.calls.results
 
 import org.jetbrains.kotlin.descriptors.CallableDescriptor
+import org.jetbrains.kotlin.descriptors.MemberDescriptor
 import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
 import org.jetbrains.kotlin.descriptors.ValueParameterDescriptor
 import org.jetbrains.kotlin.types.*
@@ -41,7 +42,8 @@ class FlatSignature<out T>(
         val valueParameterTypes: List<KotlinType?>,
         val hasExtensionReceiver: Boolean,
         val hasVarargs: Boolean,
-        val numDefaults: Int
+        val numDefaults: Int,
+        val isPlatform: Boolean
 ) {
     val isGeneric = typeParameters.isNotEmpty()
 
@@ -52,7 +54,8 @@ class FlatSignature<out T>(
                               valueParameterTypes = descriptor.extensionReceiverTypeOrEmpty() + descriptor.valueParameters.map { it.argumentValueType },
                               hasExtensionReceiver = descriptor.extensionReceiverParameter != null,
                               hasVarargs = descriptor.valueParameters.any { it.varargElementType != null },
-                              numDefaults = 0)
+                              numDefaults = 0,
+                              isPlatform = descriptor is MemberDescriptor && descriptor.isPlatform)
 
         val ValueParameterDescriptor.argumentValueType: KotlinType
             get() = varargElementType ?: type

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/results/OverloadingConflictResolver.kt

@@ -219,7 +219,7 @@ class OverloadingConflictResolver<C : Any>(
     }
 
     /**
-     * Returns `true` if `d1` is definitely not less specific than `d2`,
+     * Returns `true` if [call1] is definitely not less specific than [call2],
      * `false` otherwise.
      */
     private fun compareCallsByUsedArguments(
@@ -237,6 +237,9 @@ class OverloadingConflictResolver<C : Any>(
             if (isGeneric1 && isGeneric2) return false
         }
 
+        if (!call1.isPlatform && call2.isPlatform) return true
+        if (call1.isPlatform && !call2.isPlatform) return false
+
         return createEmptyConstraintSystem().isSignatureNotLessSpecific(call1, call2, SpecificityComparisonWithNumerics, specificityComparator)
     }