Support LIKE expressions in the new type resolver

sqlparser/lib/src/analysis/types2/resolving_visitor.dart

@@ -2,6 +2,8 @@ part of 'types.dart';
 
 const _expectInt =
     ExactTypeExpectation.laxly(ResolvedType(type: BasicType.int));
+const _expectString =
+    ExactTypeExpectation.laxly(ResolvedType(type: BasicType.text));
 
 class TypeResolver extends RecursiveVisitor<TypeExpectation, void> {
   final TypeInferenceSession session;
@@ -116,16 +118,20 @@ class TypeResolver extends RecursiveVisitor<TypeExpectation, void> {
 
     if (e is NullLiteral) {
       type = const ResolvedType(type: BasicType.nullType, nullable: true);
+      session.hintNullability(e, true);
     } else if (e is StringLiteral) {
       type = e.isBinary
           ? const ResolvedType(type: BasicType.blob)
           : const ResolvedType(type: BasicType.text);
+      session.hintNullability(e, false);
     } else if (e is BooleanLiteral) {
       type = const ResolvedType.bool();
+      session.hintNullability(e, false);
     } else if (e is NumericLiteral) {
       type = e.isInt
           ? const ResolvedType(type: BasicType.int)
           : const ResolvedType(type: BasicType.real);
+      session.hintNullability(e, false);
     }
 
     session.checkAndResolve(e, type, arg);
@@ -243,6 +249,24 @@ class TypeResolver extends RecursiveVisitor<TypeExpectation, void> {
     visit(e.operand, const NoTypeExpectation());
   }
 
+  @override
+  void visitStringComparison(
+      StringComparisonExpression e, TypeExpectation arg) {
+    session.checkAndResolve(e, const ResolvedType(type: BasicType.text), arg);
+    session.addRelationship(NullableIfSomeOtherIs(
+      e,
+      [
+        e.left,
+        e.right,
+        if (e.escape != null) e.escape,
+      ],
+    ));
+
+    visit(e.left, _expectString);
+    visit(e.right, _expectString);
+    visitNullable(e.escape, _expectString);
+  }
+
   @override
   void visitReference(Reference e, TypeExpectation arg) {
     final resolved = e.resolvedColumn;

sqlparser/lib/src/ast/expressions/simple.dart

@@ -57,6 +57,7 @@ class BinaryExpression extends Expression {
   }
 }
 
+/// A like, glob, match or regexp expression.
 class StringComparisonExpression extends Expression {
   final bool not;
   final Token operator;

sqlparser/test/analysis/types2/resolver_test.dart

@@ -127,4 +127,14 @@ void main() {
     final offsetType = _resolveFirstVariable('SELECT 0 LIMIT 1, ?');
     expect(offsetType, int);
   });
+
+  test('handles string matching expressions', () {
+    final type =
+        _resolveFirstVariable('SELECT * FROM demo WHERE content LIKE ?');
+    expect(type, const ResolvedType(type: BasicType.text));
+
+    final escapedType = _resolveFirstVariable(
+        "SELECT * FROM demo WHERE content LIKE 'foo' ESCAPE ?");
+    expect(escapedType, const ResolvedType(type: BasicType.text));
+  });
 }