[NI] Introduce methods to extend inference for several candidates

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/tower/KotlinToResolvedCallTransformer.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
- *
+ * that can be found in the license/LICENSE.txt file.
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
  */
 
 package org.jetbrains.kotlin.resolve.calls.tower
@@ -94,6 +83,7 @@ class KotlinToResolvedCallTransformer(
                     psiKotlinCall.psiCall
 
                 context.trace.record(BindingContext.ONLY_RESOLVED_CALL, psiCall, baseResolvedCall)
+                context.inferenceSession.addPartiallyResolvedCall(baseResolvedCall)
 
                 return createStubResolvedCallAndWriteItToTrace(candidate, context.trace, baseResolvedCall.diagnostics)
             }

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/components/KotlinCallCompleter.kt

@@ -38,7 +38,10 @@ class KotlinCallCompleter(
         val candidate = prepareCandidateForCompletion(factory, candidates, resolutionCallbacks)
         val completionType = candidate.prepareForCompletion(expectedType, resolutionCallbacks)
 
-        return candidate.runCompletion(completionType, diagnosticHolder, resolutionCallbacks)
+        return if (resolutionCallbacks.inferenceSession.shouldFixTypeVariables())
+            candidate.runCompletion(completionType, diagnosticHolder, resolutionCallbacks)
+        else
+            candidate.asCallResolutionResult(CallResolutionResult.Type.PARTIAL, diagnosticHolder)
     }
 
     fun createAllCandidatesResult(
@@ -176,6 +179,12 @@ class KotlinCallCompleter(
 
 interface InferenceSession {
     companion object {
-        val default = object : InferenceSession {}
+        val default = object : InferenceSession {
+            override fun shouldFixTypeVariables(): Boolean = false
+            override fun addPartiallyResolvedCall(call: CallResolutionResult) {}
+        }
     }
+
+    fun shouldFixTypeVariables(): Boolean
+    fun addPartiallyResolvedCall(call: CallResolutionResult)
 }