review comments

Author: artidoro

src/Microsoft.ML.Data/Evaluators/AnomalyDetectionEvaluator.cs

@@ -99,7 +99,7 @@ private protected override void CheckScoreAndLabelTypes(RoleMappedSchema schema)
             Host.Check(schema.Label.HasValue, "Could not find the label column");
             t = schema.Label.Value.Type;
             if (t != NumberType.Float && t.GetKeyCount() != 2)
-                throw Host.ExceptSchemaMismatch(nameof(schema), "label", schema.Label.Value.Name, "float or a 2-value KeyType", t.ToString());
+                throw Host.ExceptSchemaMismatch(nameof(schema), "label", schema.Label.Value.Name, "float or a KeyType with cardinality 2", t.ToString());
         }
 
         private protected override Aggregator GetAggregatorCore(RoleMappedSchema schema, string stratName)
@@ -665,7 +665,7 @@ private protected override void PrintFoldResultsCore(IChannel ch, Dictionary<str
 
             IDataView overall;
             if (!metrics.TryGetValue(MetricKinds.OverallMetrics, out overall))
-                throw Host.ExceptSchemaMismatch(nameof(overall.Schema), "overall metrics", MetricKinds.OverallMetrics);
+                throw Host.Except("No overall metrics found");
 
             // Find the number of anomalies, and the thresholds.
             int numAnomIndex;

src/Microsoft.ML.Data/Evaluators/BinaryClassifierEvaluator.cs

@@ -132,7 +132,7 @@ private protected override void CheckScoreAndLabelTypes(RoleMappedSchema schema)
             host.Check(schema.Label.HasValue, "Could not find the label column");
             t = schema.Label.Value.Type;
             if (t != NumberType.R4 && t != NumberType.R8 && t != BoolType.Instance && t.GetKeyCount() != 2)
-                throw host.ExceptSchemaMismatch(nameof(schema), "label", schema.Label.Value.Name, "float, double, bool, or a 2-value KeyType", t.ToString());
+                throw host.ExceptSchemaMismatch(nameof(schema), "label", schema.Label.Value.Name, "float, double, bool, or a KeyType with cardinality 2", t.ToString());
         }
 
         private protected override void CheckCustomColumnTypesCore(RoleMappedSchema schema)
@@ -1097,7 +1097,7 @@ private void CheckInputColumnTypes(Schema schema)
 
             var t = schema[(int) LabelIndex].Type;
             if (t != NumberType.R4 && t != NumberType.R8 && t != BoolType.Instance && t.GetKeyCount() != 2)
-                throw Host.ExceptSchemaMismatch(nameof(schema), "label", LabelCol, "float, double, bool or a 2-value KeyType", t.ToString());
+                throw Host.ExceptSchemaMismatch(nameof(schema), "label", LabelCol, "float, double, bool or a KeyType with cardinality 2", t.ToString());
 
             t = schema[ScoreIndex].Type;
             if (t != NumberType.Float)

src/Microsoft.ML.Data/Evaluators/ClusteringEvaluator.cs

@@ -99,7 +99,7 @@ private protected override void CheckScoreAndLabelTypes(RoleMappedSchema schema)
             if (type != null && type != NumberType.Float && !(type is KeyType keyType && keyType.Count > 0))
             {
                 throw Host.ExceptSchemaMismatch(nameof(schema), "label", schema.Label.Value.Name,
-                    "float or key", type.ToString());
+                    "float or KeyType", type.ToString());
             }
 
             var score = schema.GetUniqueColumn(MetadataUtils.Const.ScoreValueKind.Score);