Fix false positive "Cannot capture" error reporting

There is no need to report an error in case of non-top-level
capture conversion, just don't add relevant capture type in the system instead

If system can be solved successfully without captured type, then it's just fine
(see KT-13950)
In case of contradiction TYPE_INFERENCE_PARAMETER_CONSTRAINT_ERROR is reported

 #KT-13950 Fixed

compiler/frontend/src/org/jetbrains/kotlin/diagnostics/rendering/Renderers.kt

@@ -341,16 +341,16 @@ object Renderers {
         }
 
         val typeParameter = typeVariableWithCapturedConstraint.originalTypeParameter
-
-        val explanation: String
         val upperBound = TypeIntersector.getUpperBoundsAsType(typeParameter)
-        if (!KotlinBuiltIns.isNullableAny(upperBound) && capturedTypeConstructor.typeProjection.projectionKind == Variance.IN_VARIANCE) {
-            explanation = "Type parameter has an upper bound '" + result.typeRenderer.render(upperBound, RenderingContext.of(upperBound)) + "'" +
-                          " that cannot be satisfied capturing 'in' projection"
-        }
-        else {
-            explanation = "Only top-level type projections can be captured"
+
+        assert(!KotlinBuiltIns.isNullableAny(upperBound) && capturedTypeConstructor.typeProjection.projectionKind == Variance.IN_VARIANCE) {
+            "There is the only reason to report TYPE_INFERENCE_CANNOT_CAPTURE_TYPES"
         }
+
+        val explanation =
+                "Type parameter has an upper bound '" + result.typeRenderer.render(upperBound, RenderingContext.of(upperBound)) + "'" +
+                " that cannot be satisfied capturing 'in' projection"
+
         result.text(newText().normal(
                 "'" + typeParameter.name + "'" +
                 " cannot capture " +
@@ -454,4 +454,4 @@ object Renderers {
     }.asRenderer()
 }
 
-fun DescriptorRenderer.asRenderer() = SmartDescriptorRenderer(this)
+fun DescriptorRenderer.asRenderer() = SmartDescriptorRenderer(this)

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/inference/ConstraintSystemBuilderImpl.kt

@@ -152,13 +152,10 @@ open class ConstraintSystemBuilderImpl(private val mode: Mode = ConstraintSystem
             }
 
             override fun capture(type: KotlinType, typeProjection: TypeProjection): Boolean {
-                if (isMyTypeVariable(typeProjection.type)) return false
+                if (isMyTypeVariable(typeProjection.type) || depth > 0) return false
                 val myTypeVariable = getMyTypeVariable(type)
 
                 if (myTypeVariable != null && constraintPosition.isParameter()) {
-                    if (depth > 0) {
-                        errors.add(CannotCapture(constraintPosition, myTypeVariable))
-                    }
                     generateTypeParameterCaptureConstraint(myTypeVariable, typeProjection, newConstraintContext, type.isMarkedNullable)
                     return true
                 }