Apply requested changes

hibernate-core/src/main/java/org/hibernate/dialect/function/CastFunction.java

@@ -17,7 +17,6 @@ import org.hibernate.query.sqm.function.AbstractSqmSelfRenderingFunctionDescript
 import org.hibernate.query.sqm.produce.function.StandardArgumentsValidators;
 import org.hibernate.query.sqm.produce.function.StandardFunctionReturnTypeResolvers;
 import org.hibernate.query.sqm.produce.function.internal.PatternRenderer;
-import org.hibernate.sql.ast.SqlAstNodeRenderingMode;
 import org.hibernate.sql.ast.SqlAstTranslator;
 import org.hibernate.sql.ast.spi.SqlAppender;
 import org.hibernate.sql.ast.tree.SqlAstNode;
@@ -64,7 +63,7 @@ public class CastFunction extends AbstractSqmSelfRenderingFunctionDescriptor {
 
 		String cast = dialect.castPattern( sourceType, targetType );
 
-		new PatternRenderer( cast, SqlAstNodeRenderingMode.DEFAULT ).render( sqlAppender, arguments, walker );
+		new PatternRenderer( cast ).render( sqlAppender, arguments, walker );
 	}
 
 	private CastType getCastType(JdbcMapping sourceMapping) {

hibernate-core/src/main/java/org/hibernate/dialect/function/TimestampaddFunction.java

@@ -13,7 +13,6 @@ import org.hibernate.query.sqm.function.SelfRenderingFunctionSqlAstExpression;
 import org.hibernate.query.sqm.produce.function.StandardArgumentsValidators;
 import org.hibernate.query.sqm.produce.function.StandardFunctionReturnTypeResolvers;
 import org.hibernate.query.sqm.produce.function.internal.PatternRenderer;
-import org.hibernate.sql.ast.SqlAstNodeRenderingMode;
 import org.hibernate.sql.ast.SqlAstTranslator;
 import org.hibernate.sql.ast.spi.SqlAppender;
 import org.hibernate.sql.ast.tree.SqlAstNode;
@@ -56,7 +55,7 @@ public class TimestampaddFunction
 				TypeConfiguration.getSqlTemporalType( to.getExpressionType() )
 		);
 
-		new PatternRenderer( pattern, SqlAstNodeRenderingMode.DEFAULT ).render( sqlAppender, arguments, walker );
+		new PatternRenderer( pattern ).render( sqlAppender, arguments, walker );
 	}
 
 //	@Override

hibernate-core/src/main/java/org/hibernate/dialect/function/TimestampdiffFunction.java

@@ -13,7 +13,6 @@ import org.hibernate.query.sqm.function.SelfRenderingFunctionSqlAstExpression;
 import org.hibernate.query.sqm.produce.function.StandardArgumentsValidators;
 import org.hibernate.query.sqm.produce.function.StandardFunctionReturnTypeResolvers;
 import org.hibernate.query.sqm.produce.function.internal.PatternRenderer;
-import org.hibernate.sql.ast.SqlAstNodeRenderingMode;
 import org.hibernate.sql.ast.SqlAstTranslator;
 import org.hibernate.sql.ast.spi.SqlAppender;
 import org.hibernate.sql.ast.tree.SqlAstNode;
@@ -59,7 +58,7 @@ public class TimestampdiffFunction
 				TypeConfiguration.getSqlTemporalType( to.getExpressionType() )
 		);
 
-		new PatternRenderer( pattern, SqlAstNodeRenderingMode.DEFAULT ).render( sqlAppender, arguments, walker );
+		new PatternRenderer( pattern ).render( sqlAppender, arguments, walker );
 	}
 
 //	@Override

hibernate-core/src/main/java/org/hibernate/dialect/function/TrimFunction.java

@@ -12,7 +12,6 @@ import org.hibernate.query.sqm.function.AbstractSqmSelfRenderingFunctionDescript
 import org.hibernate.query.sqm.produce.function.StandardArgumentsValidators;
 import org.hibernate.query.sqm.produce.function.StandardFunctionReturnTypeResolvers;
 import org.hibernate.query.sqm.produce.function.internal.PatternRenderer;
-import org.hibernate.sql.ast.SqlAstNodeRenderingMode;
 import org.hibernate.sql.ast.SqlAstTranslator;
 import org.hibernate.sql.ast.spi.SqlAppender;
 import org.hibernate.sql.ast.tree.SqlAstNode;
@@ -48,8 +47,7 @@ public class TrimFunction extends AbstractSqmSelfRenderingFunctionDescriptor {
 
 		String trim = dialect.trimPattern( specification, trimCharacter );
 
-		new PatternRenderer( trim, SqlAstNodeRenderingMode.DEFAULT )
-				.render( sqlAppender, Collections.singletonList( sourceExpr ), walker );
+		new PatternRenderer( trim ).render( sqlAppender, Collections.singletonList( sourceExpr ), walker );
 	}
 
 //	@Override

hibernate-core/src/main/java/org/hibernate/query/sqm/produce/function/internal/PatternRenderer.java

@@ -32,6 +32,10 @@ public class PatternRenderer {
 	private final int maxParamIndex;
 	private final SqlAstNodeRenderingMode argumentRenderingMode;
 
+	public PatternRenderer(String pattern) {
+		this( pattern, SqlAstNodeRenderingMode.DEFAULT );
+	}
+
 	/**
 	 * Constructs a template renderer
 	 *

hibernate-core/src/main/java/org/hibernate/sql/ast/SqlAstNodeRenderingMode.java

@@ -6,8 +6,20 @@
  */
 package org.hibernate.sql.ast;
 
+import org.hibernate.sql.ast.tree.SqlAstNode;
+
 /**
+ * The rendering mode to use for {@link org.hibernate.sql.ast.tree.SqlAstNode}.
+ *
+ * Some functions/contexts require the use of literals/expressions rather than parameters
+ * like for example the `char` function in Derby which requires the length as literal.
+ *
+ * Another example is a function that renders a function argument into a subquery select and group by item.
+ * It can use {@link #INLINE_PARAMETERS} so that a database can match such a select item to a group by item.
+ * Without this, such queries would result in a query error.
+ * 
  * @author Christian Beikov
+ * @see SqlAstTranslator#render(SqlAstNode, SqlAstNodeRenderingMode) 
  */
 public enum SqlAstNodeRenderingMode {
 	/**
@@ -17,11 +29,15 @@ public enum SqlAstNodeRenderingMode {
 
 	/**
 	 * Render parameters as literals.
+	 * All parameters within the {@link org.hibernate.sql.ast.tree.SqlAstNode} are rendered as literals.
 	 */
 	INLINE_PARAMETERS,
 
 	/**
 	 * Don't render plain parameters. Render it as literal or as expression.
+	 * If the {@link org.hibernate.sql.ast.tree.SqlAstNode} to render is a parameter,
+	 * it will be rendered either as literal or wrapped into a semantically equivalent expression
+	 * such that it doesn't appear as plain parameter.
 	 */
 	NO_PLAIN_PARAMETER
 }

hibernate-core/src/main/java/org/hibernate/sql/ast/spi/AbstractSqlAstTranslator.java

@@ -124,8 +124,9 @@ public abstract class AbstractSqlAstTranslator<T extends JdbcOperation>
 						case Types.FLOAT:
 						case Types.NUMERIC:
 						case Types.DECIMAL:
+							appendSql( '(' );
 							sqlAstNode.accept( this );
-							appendSql( "+0" );
+							appendSql( "+0)" );
 							break;
 						case Types.CHAR:
 						case Types.VARCHAR: