Provide lints on insert statements that will fail

moor_generator/lib/src/model/sql_query.dart

@@ -10,6 +10,8 @@ final _leadingDigits = RegExp(r'^\d*');
 abstract class SqlQuery {
   final String name;
   final AnalysisContext fromContext;
+  List<AnalysisError> lints;
+
   String get sql => fromContext.sql;
 
   /// The variables that appear in the [sql] query. We support three kinds of

moor_generator/lib/src/parser/sql/lints/linter.dart

@@ -0,0 +1,82 @@
+import 'package:sqlparser/sqlparser.dart';
+
+import '../query_handler.dart';
+
+class Linter {
+  final QueryHandler handler;
+  final List<AnalysisError> lints = [];
+
+  Linter(this.handler);
+
+  void reportLints() {
+    handler.context.root.accept(_LintingVisitor(this));
+  }
+}
+
+class _LintingVisitor extends RecursiveVisitor<void> {
+  final Linter linter;
+
+  _LintingVisitor(this.linter);
+
+  @override
+  void visitInsertStatement(InsertStatement e) {
+    final targeted = e.resolvedTargetColumns;
+    if (targeted == null) return;
+
+    // First, check that the amount of values matches the declaration.
+    e.source.when(
+      isValues: (values) {
+        for (var tuple in values.values) {
+          if (tuple.expressions.length != targeted.length) {
+            linter.lints.add(AnalysisError(
+              type: AnalysisErrorType.other,
+              message: 'Expected tuple to have ${targeted.length} values',
+              relevantNode: tuple,
+            ));
+          }
+        }
+      },
+      isSelect: (select) {
+        final columns = select.stmt.resolvedColumns;
+
+        if (columns.length != targeted.length) {
+          linter.lints.add(AnalysisError(
+            type: AnalysisErrorType.other,
+            message: 'This select statement should return ${targeted.length} '
+                'columns, but actually returns ${columns.length}',
+            relevantNode: select.stmt,
+          ));
+        }
+      },
+    );
+
+    // second, check that no required columns are left out
+    final specifiedTable =
+        linter.handler.mapper.tableToMoor(e.table.resolved as Table);
+    final required =
+        specifiedTable.columns.where((c) => c.requiredDuringInsert).toList();
+
+    if (required.isNotEmpty && e.source is DefaultValues) {
+      linter.lints.add(AnalysisError(
+        type: AnalysisErrorType.other,
+        message: 'This table has columns without default values, so defaults '
+            'can\'t be used for insert.',
+        relevantNode: e.table,
+      ));
+    } else {
+      final notPresent = required.where((c) => !targeted
+          .any((t) => t.name.toUpperCase() == c.name.name.toUpperCase()));
+
+      if (notPresent.isNotEmpty) {
+        final msg = notPresent.join(', ');
+
+        linter.lints.add(AnalysisError(
+          type: AnalysisErrorType.other,
+          message: 'Some columns are required but not present here. Expected '
+              'values for $msg.',
+          relevantNode: e.source.childNodes.first,
+        ));
+      }
+    }
+  }
+}

moor_generator/lib/src/parser/sql/query_handler.dart

@@ -5,6 +5,7 @@ import 'package:moor_generator/src/utils/type_converter_hint.dart';
 import 'package:sqlparser/sqlparser.dart' hide ResultColumn;
 
 import 'affected_tables_visitor.dart';
+import 'lints/linter.dart';
 
 class QueryHandler {
   final String name;
@@ -19,11 +20,20 @@ class QueryHandler {
   QueryHandler(this.name, this.context, this.mapper);
 
   SqlQuery handle() {
-    final root = context.root;
     _foundVariables = mapper.extractVariables(context);
 
     _verifyNoSkippedIndexes();
+    final query = _mapToMoor();
 
+    final linter = Linter(this);
+    linter.reportLints();
+    query.lints = linter.lints;
+
+    return query;
+  }
+
+  SqlQuery _mapToMoor() {
+    final root = context.root;
     if (root is SelectStatement) {
       return _handleSelect();
     } else if (root is UpdateStatement ||

moor_generator/lib/src/parser/sql/sql_parser.dart

@@ -54,5 +54,15 @@ class SqlParser {
         log.warning('Error while generating APIs for ${context.sql}', e, s);
       }
     });
+
+    // report lints
+    for (var query in foundQueries) {
+      for (var lint in query.lints) {
+        session.errors.add(MoorError(
+          critical: false,
+          message: 'Lint for ${query.name}: $lint',
+        ));
+      }
+    }
   }
 }

sqlparser/lib/src/analysis/error.dart

@@ -56,4 +56,5 @@ enum AnalysisErrorType {
   ambiguousReference,
 
   unknownFunction,
+  other,
 }