NI: Allow to resolve to functions with SAM conversion and passing array without spread as vararg (with warning)

^KT-35224 Fixed

compiler/frontend/src/org/jetbrains/kotlin/diagnostics/Errors.java

@@ -765,6 +765,7 @@ public interface Errors {
     DiagnosticFactory1<PsiElement, TypeParameterDescriptor> TYPE_INFERENCE_ONLY_INPUT_TYPES = DiagnosticFactory1.create(ERROR);
     DiagnosticFactory1<PsiElement, InferenceErrorData> TYPE_INFERENCE_UPPER_BOUND_VIOLATED = DiagnosticFactory1.create(ERROR);
     DiagnosticFactory2<KtElement, KotlinType, KotlinType> TYPE_INFERENCE_EXPECTED_TYPE_MISMATCH = DiagnosticFactory2.create(ERROR);
+    DiagnosticFactory0<PsiElement> TYPE_INFERENCE_CANDIDATE_WITH_SAM_AND_VARARG = DiagnosticFactory0.create(WARNING);
 
     DiagnosticFactory0<KtExpression> TYPE_INFERENCE_FAILED_ON_SPECIAL_CONSTRUCT = DiagnosticFactory0.create(ERROR, SPECIAL_CONSTRUCT_TOKEN);
 

compiler/frontend/src/org/jetbrains/kotlin/diagnostics/rendering/DefaultErrorMessages.java

@@ -859,6 +859,7 @@ public class DefaultErrorMessages {
                                                  "(argument types, receiver type or expected type). Try to specify it explicitly.", NAME);
         MAP.put(TYPE_INFERENCE_UPPER_BOUND_VIOLATED, "{0}", TYPE_INFERENCE_UPPER_BOUND_VIOLATED_RENDERER);
         MAP.put(TYPE_INFERENCE_EXPECTED_TYPE_MISMATCH, "Type inference failed. Expected type mismatch: inferred type is {1} but {0} was expected", RENDER_TYPE, RENDER_TYPE);
+        MAP.put(TYPE_INFERENCE_CANDIDATE_WITH_SAM_AND_VARARG, "Please use spread operator to pass an array as vararg. It will be an error in 1.5.");
 
         MAP.put(TYPE_INFERENCE_FAILED_ON_SPECIAL_CONSTRUCT, "Type inference for control flow expression failed. Please specify its type explicitly.");
 

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/DiagnosticReporterByTrackingStrategy.kt

@@ -175,6 +175,10 @@ class DiagnosticReporterByTrackingStrategy(
                 }
 
             }
+
+            ResolvedToSamWithVarargDiagnostic::class.java -> {
+                trace.report(TYPE_INFERENCE_CANDIDATE_WITH_SAM_AND_VARARG.on(callArgument.psiCallArgument.valueArgument.asElement()))
+            }
         }
     }