Make the parser set a span on each AST node.

sqlparser/lib/src/reader/parser/crud.dart

@@ -274,6 +274,7 @@ mixin CrudParser on ParserBase {
 
   OrderByBase _orderBy() {
     if (_matchOne(TokenType.order)) {
+      final orderToken = _previous;
       _consume(TokenType.by, 'Expected "BY" after "ORDER" token');
       final terms = <OrderingTermBase>[];
       do {
@@ -290,7 +291,7 @@ mixin CrudParser on ParserBase {
           ..setSpan(termPlaceholder.first, termPlaceholder.last);
       }
 
-      return OrderBy(terms: terms);
+      return OrderBy(terms: terms)..setSpan(orderToken, _previous);
     }
     return null;
   }
@@ -307,7 +308,8 @@ mixin CrudParser on ParserBase {
         ..setSpan(expr.first, expr.last);
     }
 
-    return OrderingTerm(expression: expr, orderingMode: mode);
+    return OrderingTerm(expression: expr, orderingMode: mode)
+      ..setSpan(expr.first, _previous);
   }
 
   @override
@@ -356,6 +358,8 @@ mixin CrudParser on ParserBase {
 
   DeleteStatement _deleteStmt() {
     if (!_matchOne(TokenType.delete)) return null;
+    final deleteToken = _previous;
+
     _consume(TokenType.from, 'Expected a FROM here');
 
     final table = _tableReference();
@@ -368,7 +372,8 @@ mixin CrudParser on ParserBase {
       where = expression();
     }
 
-    return DeleteStatement(from: table, where: where);
+    return DeleteStatement(from: table, where: where)
+      ..setSpan(deleteToken, _previous);
   }
 
   UpdateStatement _update() {
@@ -393,7 +398,8 @@ mixin CrudParser on ParserBase {
       _consume(TokenType.equal, 'Expected = after the column name');
       final expr = expression();
 
-      set.add(SetComponent(column: reference, expression: expr));
+      set.add(SetComponent(column: reference, expression: expr)
+        ..setSpan(columnName, _previous));
     } while (_matchOne(TokenType.comma));
 
     final where = _where();
@@ -428,7 +434,7 @@ mixin CrudParser on ParserBase {
         insertMode = InsertMode.insert;
       }
     } else {
-      // is it wasn't an insert, it must have been a replace
+      // if it wasn't an insert, it must have been a replace
       insertMode = InsertMode.replace;
     }
     assert(insertMode != null);
@@ -440,7 +446,8 @@ mixin CrudParser on ParserBase {
     if (_matchOne(TokenType.leftParen)) {
       do {
         final columnRef = _consumeIdentifier('Expected a column');
-        targetColumns.add(Reference(columnName: columnRef.identifier));
+        targetColumns.add(Reference(columnName: columnRef.identifier)
+          ..setSpan(columnRef, columnRef));
       } while (_matchOne(TokenType.comma));
 
       _consume(TokenType.rightParen,

sqlparser/lib/src/reader/parser/expressions.dart

@@ -20,15 +20,20 @@ mixin ExpressionParser on ParserBase {
 
   Expression _case() {
     if (_matchOne(TokenType.$case)) {
+      final caseToken = _previous;
+
       final base = _check(TokenType.when) ? null : _or();
       final whens = <WhenComponent>[];
       Expression $else;
 
       while (_matchOne(TokenType.when)) {
+        final whenToken = _previous;
+
         final whenExpr = _or();
         _consume(TokenType.then, 'Expected THEN');
         final then = _or();
-        whens.add(WhenComponent(when: whenExpr, then: then));
+        whens.add(WhenComponent(when: whenExpr, then: then)
+          ..setSpan(whenToken, _previous));
       }
 
       if (_matchOne(TokenType.$else)) {
@@ -36,7 +41,8 @@ mixin ExpressionParser on ParserBase {
       }
 
       _consume(TokenType.end, 'Expected END to finish the case operator');
-      return CaseExpression(whens: whens, base: base, elseExpr: $else);
+      return CaseExpression(whens: whens, base: base, elseExpr: $else)
+        ..setSpan(caseToken, _previous);
     }
 
     return _or();
@@ -52,7 +58,8 @@ mixin ExpressionParser on ParserBase {
     while (_match(types)) {
       final operator = _previous;
       final right = higherPrecedence();
-      expression = BinaryExpression(expression, operator, right);
+      expression = BinaryExpression(expression, operator, right)
+        ..setSpan(expression.first, _previous);
     }
     return expression;
   }
@@ -68,7 +75,8 @@ mixin ExpressionParser on ParserBase {
       _matchOne(TokenType.$in);
 
       final inside = _variableOrNull() ?? _consumeTuple(orSubQuery: true);
-      return InExpression(left: left, inside: inside, not: not);
+      return InExpression(left: left, inside: inside, not: not)
+        ..setSpan(left.first, _previous);
     }
 
     return left;
@@ -79,6 +87,7 @@ mixin ExpressionParser on ParserBase {
   /// expressions.
   Expression _equals() {
     var expression = _comparison();
+    final first = expression.first;
 
     final ops = const [
       TokenType.equal,
@@ -104,15 +113,18 @@ mixin ExpressionParser on ParserBase {
         final upper = _comparison();
 
         expression = BetweenExpression(
-            not: not, check: expression, lower: lower, upper: upper);
+            not: not, check: expression, lower: lower, upper: upper)
+          ..setSpan(first, _previous);
       } else if (_match(ops)) {
         final operator = _previous;
         if (operator.type == TokenType.$is) {
           final not = _match(const [TokenType.not]);
           // special case: is not expression
-          expression = IsExpression(not, expression, _comparison());
+          expression = IsExpression(not, expression, _comparison())
+            ..setSpan(first, _previous);
         } else {
-          expression = BinaryExpression(expression, operator, _comparison());
+          expression = BinaryExpression(expression, operator, _comparison())
+            ..setSpan(first, _previous);
         }
       } else if (_checkAnyWithNot(stringOps)) {
         final not = _matchOne(TokenType.not);
@@ -130,7 +142,8 @@ mixin ExpressionParser on ParserBase {
             left: expression,
             operator: operator,
             right: right,
-            escape: escape);
+            escape: escape)
+          ..setSpan(first, _previous);
       } else {
         break; // no matching operator with this precedence was found
       }
@@ -175,14 +188,17 @@ mixin ExpressionParser on ParserBase {
     ])) {
       final operator = _previous;
       final expression = _unary();
-      return UnaryExpression(operator, expression);
+      return UnaryExpression(operator, expression)
+        ..setSpan(operator, expression.last);
     } else if (_matchOne(TokenType.exists)) {
+      final existsToken = _previous;
       _consume(
           TokenType.leftParen, 'Expected opening parenthesis after EXISTS');
       final selectStmt = select();
       _consume(TokenType.rightParen,
           'Expected closing paranthesis to finish EXISTS expression');
-      return ExistsExpression(select: selectStmt);
+      return ExistsExpression(select: selectStmt)
+        ..setSpan(existsToken, _previous);
     }
 
     return _postfix();
@@ -255,11 +271,11 @@ mixin ExpressionParser on ParserBase {
         if (_peek.type == TokenType.select) {
           final stmt = select();
           _consume(TokenType.rightParen, 'Expected a closing bracket');
-          return SubQuery(select: stmt);
+          return SubQuery(select: stmt)..setSpan(left, _previous);
         } else {
           final expr = expression();
           _consume(TokenType.rightParen, 'Expected a closing bracket');
-          return Parentheses(left, expr, token);
+          return Parentheses(left, expr, token)..setSpan(left, _previous);
         }
         break;
       case TokenType.identifier:

sqlparser/test/parser/expression_test.dart

@@ -146,6 +146,8 @@ void main() {
         final tokens = scanner.scanTokens();
         final parser = Parser(tokens);
         final expression = parser.expression();
+        enforceHasSpan(expression);
+
         enforceEqual(expression, expected);
       });
     });

sqlparser/test/parser/moor_file_test.dart

@@ -2,6 +2,8 @@ import 'package:sqlparser/sqlparser.dart';
 import 'package:sqlparser/src/utils/ast_equality.dart';
 import 'package:test/test.dart';
 
+import 'utils.dart';
+
 const content = r'''
 import 'other.dart';
 import 'another.moor';
@@ -19,6 +21,7 @@ void main() {
   test('parses moor files', () {
     final parsed = SqlEngine(useMoorExtensions: true).parseMoorFile(content);
     final file = parsed.rootNode;
+    enforceHasSpan(file);
 
     enforceEqual(
       file,

sqlparser/test/parser/utils.dart

@@ -20,6 +20,7 @@ IdentifierToken identifier(String content) {
 
 void testStatement(String sql, AstNode expected, {bool moorMode = false}) {
   final parsed = SqlEngine(useMoorExtensions: moorMode).parse(sql).rootNode;
+  enforceHasSpan(parsed);
   enforceEqual(parsed, expected);
 }
 
@@ -34,3 +35,14 @@ void testAll(Map<String, AstNode> testCases) {
     });
   });
 }
+
+/// The parser should make sure [AstNode.hasSpan] is true on relevant nodes.
+void enforceHasSpan(AstNode node) {
+  final problematic = [node]
+      .followedBy(node.allDescendants)
+      .firstWhere((node) => !node.hasSpan, orElse: () => null);
+
+  if (problematic != null) {
+    throw ArgumentError('Node $problematic did not have a span');
+  }
+}