[NI] Decrease only input types check diagnostic level to warning

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

@@ -764,6 +764,7 @@ public interface Errors {
     DiagnosticFactory1<PsiElement, InferenceErrorData> TYPE_INFERENCE_PARAMETER_CONSTRAINT_ERROR = DiagnosticFactory1.create(ERROR);
     DiagnosticFactory0<PsiElement> TYPE_INFERENCE_INCORPORATION_ERROR = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory1<PsiElement, TypeParameterDescriptor> TYPE_INFERENCE_ONLY_INPUT_TYPES = DiagnosticFactory1.create(ERROR);
+    DiagnosticFactory1<PsiElement, TypeParameterDescriptor> TYPE_INFERENCE_ONLY_INPUT_TYPES_WARNING = DiagnosticFactory1.create(WARNING);
     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);

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

@@ -858,6 +858,8 @@ public class DefaultErrorMessages {
         MAP.put(TYPE_INFERENCE_INCORPORATION_ERROR, "Type inference failed. Please try to specify type arguments explicitly.");
         MAP.put(TYPE_INFERENCE_ONLY_INPUT_TYPES, "Type inference failed. The value of the type parameter {0} should be mentioned in input types " +
                                                  "(argument types, receiver type or expected type). Try to specify it explicitly.", NAME);
+        MAP.put(TYPE_INFERENCE_ONLY_INPUT_TYPES_WARNING, "Type inference failed. The value of the type parameter {0} should be mentioned in input types " +
+                                                 "(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.");

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

@@ -67,7 +67,10 @@ class DiagnosticReporterByTrackingStrategy(
             OnlyInputTypesDiagnostic::class.java -> {
                 val typeVariable = (diagnostic as OnlyInputTypesDiagnostic).typeVariable as? TypeVariableFromCallableDescriptor ?: return
                 psiKotlinCall.psiCall.calleeExpression?.let {
-                    trace.report(TYPE_INFERENCE_ONLY_INPUT_TYPES.on(it, typeVariable.originalTypeParameter))
+                    val factory = if (context.languageVersionSettings.supportsFeature(LanguageFeature.NonStrictOnlyInputTypesChecks))
+                        TYPE_INFERENCE_ONLY_INPUT_TYPES_WARNING
+                    else TYPE_INFERENCE_ONLY_INPUT_TYPES
+                    trace.report(factory.on(it, typeVariable.originalTypeParameter))
                 }
             }
         }