Allow field name declaration in row literal

Add support for `row(a 1, b 2)` instead of the much more complex
`cast(row(1, 2) as row(a integer, b integer))`.

Author: dain

core/trino-grammar/src/main/antlr4/io/trino/grammar/sql/SqlBase.g4

@@ -574,7 +574,7 @@ primaryExpression
     | QUESTION_MARK                                                                       #parameter
     | POSITION '(' valueExpression IN valueExpression ')'                                 #position
     | '(' expression (',' expression)+ ')'                                                #rowConstructor
-    | ROW '(' expression (',' expression)* ')'                                            #rowConstructor
+    | ROW '(' fieldConstructor (',' fieldConstructor)* ')'                                        #rowConstructor
     | name=LISTAGG '(' setQuantifier? expression (',' string)?
         (ON OVERFLOW listAggOverflowBehavior)? ')'
         (WITHIN GROUP '(' ORDER BY sortItem (',' sortItem)* ')')
@@ -646,6 +646,10 @@ primaryExpression
      ')'                                                                                  #jsonArray
     ;
 
+fieldConstructor
+    : expression (AS? identifier)?
+    ;
+
 jsonPathInvocation
     : jsonValueExpression ',' path=string
         (AS pathName=identifier)?

core/trino-main/src/main/java/io/trino/sql/analyzer/AggregationAnalyzer.java

@@ -701,10 +701,16 @@ protected Boolean visitTryExpression(TryExpression node, Void context)
         @Override
         protected Boolean visitRow(Row node, Void context)
         {
-            return node.getItems().stream()
+            return node.getFields().stream()
                     .allMatch(item -> process(item, context));
         }
 
+        @Override
+        protected Boolean visitRowField(Row.Field node, Void context)
+        {
+            return process(node.getExpression(), context);
+        }
+
         @Override
         protected Boolean visitParameter(Parameter node, Void context)
         {

core/trino-main/src/main/java/io/trino/sql/analyzer/ExpressionAnalyzer.java

@@ -679,11 +679,11 @@ public Type process(Node node, @Nullable Context context)
         @Override
         protected Type visitRow(Row node, Context context)
         {
-            List<Type> types = node.getItems().stream()
-                    .map(child -> process(child, context))
+            List<RowType.Field> fields = node.getFields().stream()
+                    .map(field -> new RowType.Field(field.getName().map(Identifier::getCanonicalValue), process(field.getExpression(), context)))
                     .collect(toImmutableList());
 
-            Type type = RowType.anonymous(types);
+            Type type = RowType.from(fields);
             return setExpressionType(node, type);
         }
 

core/trino-main/src/main/java/io/trino/sql/analyzer/StatementAnalyzer.java

@@ -3929,7 +3929,7 @@ protected Scope visitValues(Values node, Optional<Scope> scope)
                     // TODO coerce the whole Row and add an Optimizer rule that converts CAST(ROW(...) AS ...) into ROW(CAST(...), CAST(...), ...).
                     //  The rule would also handle Row-type expressions that were specified as CAST(ROW). It should support multiple casts over a ROW.
                     for (int i = 0; i < actualType.getTypeParameters().size(); i++) {
-                        Expression item = ((Row) row).getItems().get(i);
+                        Expression item = ((Row) row).getFields().get(i).getExpression();
                         Type actualItemType = actualType.getTypeParameters().get(i);
                         Type expectedItemType = commonSuperType.getTypeParameters().get(i);
                         if (!actualItemType.equals(expectedItemType)) {

core/trino-main/src/main/java/io/trino/sql/ir/ExpressionFormatter.java

@@ -16,6 +16,7 @@
 import com.google.common.base.CharMatcher;
 import com.google.common.base.Joiner;
 import com.google.common.collect.ImmutableList;
+import io.trino.spi.type.RowType;
 import io.trino.sql.planner.Symbol;
 
 import java.util.List;
@@ -67,9 +68,19 @@ protected String visitArray(Array node, Void context)
         @Override
         protected String visitRow(Row node, Void context)
         {
-            return node.items().stream()
-                    .map(child -> process(child, context))
-                    .collect(joining(", ", "ROW (", ")"));
+            List<RowType.Field> fieldTypes = ((RowType) node.type()).getFields();
+
+            StringBuilder builder = new StringBuilder();
+            builder.append("ROW (");
+            for (int i = 0; i < fieldTypes.size(); i++) {
+                if (i > 0) {
+                    builder.append(", ");
+                }
+                builder.append(node.items().get(i).accept(this, context));
+                fieldTypes.get(i).getName().ifPresent(name -> builder.append(" AS ").append(name));
+            }
+            builder.append(")");
+            return builder.toString();
         }
 
         @Override

core/trino-main/src/main/java/io/trino/sql/ir/ExpressionTreeRewriter.java

@@ -110,7 +110,7 @@ protected Expression visitRow(Row node, Context<C> context)
             List<Expression> items = rewrite(node.items(), context);
 
             if (!sameElements(node.items(), items)) {
-                return new Row(items);
+                return new Row(items, node.type());
             }
 
             return node;

core/trino-main/src/main/java/io/trino/sql/ir/Row.java

@@ -16,15 +16,15 @@
 import com.fasterxml.jackson.databind.annotation.JsonSerialize;
 import com.google.common.collect.ImmutableList;
 import io.trino.spi.type.RowType;
-import io.trino.spi.type.Type;
 
 import java.util.List;
+import java.util.Optional;
 import java.util.stream.Collectors;
 
 import static java.util.Objects.requireNonNull;
 
 @JsonSerialize
-public record Row(List<Expression> items)
+public record Row(List<Expression> items, RowType type)
         implements Expression
 {
     public Row
@@ -33,10 +33,9 @@ public record Row(List<Expression> items)
         items = ImmutableList.copyOf(items);
     }
 
-    @Override
-    public Type type()
+    public Row(List<Expression> items)
     {
-        return RowType.anonymous(items.stream().map(Expression::type).collect(Collectors.toList()));
+        this(items, RowType.anonymous(items.stream().map(Expression::type).toList()));
     }
 
     @Override
@@ -60,4 +59,25 @@ public String toString()
                         .collect(Collectors.joining(", ")) +
                 ")";
     }
+
+    @JsonSerialize
+    public record Field(Optional<String> name, Expression value)
+    {
+        public Field
+        {
+            requireNonNull(name, "name is null");
+            requireNonNull(value, "value is null");
+        }
+
+        public static Field anonymousField(Expression value)
+        {
+            return new Field(Optional.empty(), value);
+        }
+
+        @Override
+        public String toString()
+        {
+            return name.map(n -> n + " " + value).orElseGet(value::toString);
+        }
+    }
 }

core/trino-main/src/main/java/io/trino/sql/ir/optimizer/IrExpressionOptimizer.java

@@ -192,7 +192,7 @@ private Optional<Expression> processChildren(Expression expression, Session sess
             case Logical logical -> process(logical.terms(), session, bindings).map(arguments -> new Logical(logical.operator(), arguments));
             case Call call -> process(call.arguments(), session, bindings).map(arguments -> new Call(call.function(), arguments));
             case Array array -> process(array.elements(), session, bindings).map(elements -> new Array(array.elementType(), elements));
-            case Row row -> process(row.items(), session, bindings).map(fields -> new Row(fields));
+            case Row row -> process(row.items(), session, bindings).map(fields -> new Row(fields, row.type()));
             case Between between -> {
                 Optional<Expression> value = process(between.value(), session, bindings);
                 Optional<Expression> min = process(between.min(), session, bindings);

core/trino-main/src/main/java/io/trino/sql/ir/optimizer/rule/EvaluateRow.java

@@ -37,7 +37,7 @@ public class EvaluateRow
     @Override
     public Optional<Expression> apply(Expression expression, Session session, Map<Symbol, Expression> bindings)
     {
-        if (!(expression instanceof Row(List<Expression> fields)) || !fields.stream().allMatch(Constant.class::isInstance)) {
+        if (!(expression instanceof Row(List<Expression> fields, RowType _)) || !fields.stream().allMatch(Constant.class::isInstance)) {
             return Optional.empty();
         }
 

core/trino-main/src/main/java/io/trino/sql/planner/RelationPlanner.java

@@ -1764,10 +1764,16 @@ protected RelationPlan visitValues(Values node, Void context)
 
         ImmutableList.Builder<Expression> rows = ImmutableList.builder();
         for (io.trino.sql.tree.Expression row : node.getRows()) {
-            if (row instanceof io.trino.sql.tree.Row) {
-                rows.add(new Row(((io.trino.sql.tree.Row) row).getItems().stream()
-                        .map(item -> coerceIfNecessary(analysis, item, translationMap.rewrite(item)))
-                        .collect(toImmutableList())));
+            if (row instanceof io.trino.sql.tree.Row astRow) {
+                ImmutableList.Builder<Expression> fields = ImmutableList.builder();
+                ImmutableList.Builder<RowType.Field> typeFields = ImmutableList.builder();
+                for (int i = 0; i < astRow.getFields().size(); i++) {
+                    io.trino.sql.tree.Row.Field astField = astRow.getFields().get(i);
+                    Expression expression = coerceIfNecessary(analysis, astField.getExpression(), translationMap.rewrite(astField.getExpression()));
+                    fields.add(expression);
+                    typeFields.add(new RowType.Field(astField.getName().map(Identifier::getCanonicalValue), expression.type()));
+                }
+                rows.add(new Row(fields.build(), RowType.from(typeFields.build())));
             }
             else if (analysis.getType(row) instanceof RowType) {
                 rows.add(coerceIfNecessary(analysis, row, translationMap.rewrite(row)));

core/trino-main/src/main/java/io/trino/sql/planner/TranslationMap.java

@@ -150,6 +150,7 @@
 import static io.trino.sql.ir.Comparison.Operator.NOT_EQUAL;
 import static io.trino.sql.ir.IrExpressions.ifExpression;
 import static io.trino.sql.ir.IrExpressions.not;
+import static io.trino.sql.planner.QueryPlanner.coerceIfNecessary;
 import static io.trino.sql.planner.ScopeAware.scopeAwareKey;
 import static io.trino.sql.tree.JsonQuery.EmptyOrErrorBehavior.ERROR;
 import static io.trino.sql.tree.JsonQuery.QuotesBehavior.KEEP;
@@ -545,11 +546,17 @@ private io.trino.sql.ir.Expression translate(NotExpression expression)
         return not(plannerContext.getMetadata(), translateExpression(expression.getValue()));
     }
 
-    private io.trino.sql.ir.Expression translate(Row expression)
+    private io.trino.sql.ir.Expression translate(Row row)
     {
-        return new io.trino.sql.ir.Row(expression.getItems().stream()
-                .map(this::translateExpression)
-                .collect(toImmutableList()));
+        ImmutableList.Builder<io.trino.sql.ir.Expression> fields = ImmutableList.builder();
+        ImmutableList.Builder<RowType.Field> typeFields = ImmutableList.builder();
+        for (int i = 0; i < row.getFields().size(); i++) {
+            io.trino.sql.tree.Row.Field field = row.getFields().get(i);
+            io.trino.sql.ir.Expression expression = coerceIfNecessary(analysis, field.getExpression(), translateExpression(field.getExpression()));
+            fields.add(expression);
+            typeFields.add(new RowType.Field(field.getName().map(Identifier::getCanonicalValue), expression.type()));
+        }
+        return new io.trino.sql.ir.Row(fields.build(), RowType.from(typeFields.build()));
     }
 
     private io.trino.sql.ir.Expression translate(ComparisonExpression expression)

core/trino-main/src/main/java/io/trino/sql/planner/iterative/rule/ExpressionRewriteRuleSet.java

@@ -300,18 +300,20 @@ public Result apply(ValuesNode valuesNode, Captures captures, Context context)
 
             boolean anyRewritten = false;
             ImmutableList.Builder<Expression> rows = ImmutableList.builder();
-            for (Expression row : valuesNode.getRows().get()) {
+            for (Expression original : valuesNode.getRows().get()) {
                 Expression rewritten;
-                if (row instanceof Row) {
+                if (original instanceof Row row) {
                     // preserve the structure of row
-                    rewritten = new Row(((Row) row).items().stream()
-                            .map(item -> rewriter.rewrite(item, context))
-                            .collect(toImmutableList()));
+                    rewritten = new Row(
+                            row.items().stream()
+                                    .map(item -> rewriter.rewrite(item, context))
+                                    .collect(toImmutableList()),
+                            row.type());
                 }
                 else {
-                    rewritten = rewriter.rewrite(row, context);
+                    rewritten = rewriter.rewrite(original, context);
                 }
-                if (!row.equals(rewritten)) {
+                if (!original.equals(rewritten)) {
                     anyRewritten = true;
                 }
                 rows.add(rewritten);

core/trino-main/src/main/java/io/trino/sql/planner/iterative/rule/PushCastIntoRow.java

@@ -20,73 +20,57 @@
 import io.trino.sql.ir.Expression;
 import io.trino.sql.ir.ExpressionTreeRewriter;
 import io.trino.sql.ir.Row;
-import io.trino.type.UnknownType;
 
 /**
  * Transforms expressions of the form
  *
  * <pre>
  *  CAST(
- *      CAST(
- *          ROW(x, y)
- *          AS row(f1 type1, f2 type2))
- *      AS row(g1 type3, g2 type4))
+ *      ROW(x, y)
+ *      AS row(f1 type1, f2 type2))
  * </pre>
  *
  * to
  *
  * <pre>
- *  CAST(
- *      ROW(
- *          CAST(x AS type1),
- *          CAST(y AS type2))
- *      AS row(g1 type3, g2 type4))
+ *  ROW(
+ *      CAST(x AS type1) as f1,
+ *      CAST(y AS type2) as f2)
  * </pre>
- *
- * Note: it preserves the top-level CAST if the row type has field names because the names are needed by the ROW to JSON cast
- *       TODO: ideally, the types involved in ROW to JSON cast should be captured at analysis time and
- *         remain fixed for the duration of the optimization process so as to have flexibility in terms
- *         of removing field names, which are irrelevant in the IR
  */
 public class PushCastIntoRow
         extends ExpressionRewriteRuleSet
 {
     public PushCastIntoRow()
     {
-        super((expression, context) -> ExpressionTreeRewriter.rewriteWith(new Rewriter(), expression, false));
+        super((expression, context) -> ExpressionTreeRewriter.rewriteWith(new Rewriter(), expression, null));
     }
 
     private static class Rewriter
-            extends io.trino.sql.ir.ExpressionRewriter<Boolean>
+            extends io.trino.sql.ir.ExpressionRewriter<Void>
     {
         @Override
-        public Expression rewriteCast(Cast node, Boolean inRowCast, ExpressionTreeRewriter<Boolean> treeRewriter)
+        public Expression rewriteCast(Cast node, Void context, ExpressionTreeRewriter<Void> treeRewriter)
         {
-            if (!(node.type() instanceof RowType type)) {
-                return treeRewriter.defaultRewrite(node, false);
+            if (!(node.type() instanceof RowType castToType)) {
+                return treeRewriter.defaultRewrite(node, null);
             }
 
-            // if inRowCast == true or row is anonymous, we're free to push Cast into Row. An enclosing CAST(... AS ROW) will take care of preserving field names
-            // otherwise, apply recursively with inRowCast == true and don't push this one
-
-            if (inRowCast || type.getFields().stream().allMatch(field -> field.getName().isEmpty())) {
-                Expression value = treeRewriter.rewrite(node.expression(), true);
-
-                if (value instanceof Row row) {
-                    ImmutableList.Builder<Expression> items = ImmutableList.builder();
-                    for (int i = 0; i < row.items().size(); i++) {
-                        Expression item = row.items().get(i);
-                        Type itemType = type.getFields().get(i).getType();
-                        if (!(itemType instanceof UnknownType)) {
-                            item = new Cast(item, itemType);
-                        }
-                        items.add(item);
+            Expression value = treeRewriter.rewrite(node.expression(), null);
+            if (value instanceof Row(java.util.List<Expression> expressions, RowType type)) {
+                ImmutableList.Builder<Expression> items = ImmutableList.builder();
+                for (int i = 0; i < expressions.size(); i++) {
+                    Expression fieldValue = expressions.get(i);
+                    Type fieldType = castToType.getFields().get(i).getType();
+                    if (!fieldValue.type().equals(fieldType)) {
+                        fieldValue = new Cast(fieldValue, fieldType);
                     }
-                    return new Row(items.build());
+                    items.add(fieldValue);
                 }
+                return new Row(items.build(), castToType);
             }
 
-            return treeRewriter.defaultRewrite(node, true);
+            return treeRewriter.defaultRewrite(node, null);
         }
     }
 }

core/trino-main/src/main/java/io/trino/sql/planner/iterative/rule/TransformCorrelatedSingleRowSubqueryToProject.java

@@ -93,7 +93,7 @@ public Result apply(CorrelatedJoinNode parent, Captures captures, Context contex
                         .putIdentities(parent.getInput().getOutputSymbols());
                 forEachPair(
                         values.getOutputSymbols().stream(),
-                        row.items().stream(),
+                        row.children().stream(),
                         assignments::put);
                 return Result.ofPlanNode(projectNode(parent.getInput(), assignments.build(), context));
             }