Add PhysicalExpr optimizer and cast unwrapping

Author: adriangb

Cargo.lock

@@ -37,6 +37,7 @@ use datafusion_common::pruning::{
 };
 use datafusion_common::{exec_err, Result};
 use datafusion_datasource::PartitionedFile;
+use datafusion_physical_expr::simplifier::PhysicalExprSimplifier;
 use datafusion_physical_expr::PhysicalExprSchemaRewriter;
 use datafusion_physical_expr_common::physical_expr::PhysicalExpr;
 use datafusion_physical_optimizer::pruning::PruningPredicate;
@@ -262,7 +263,13 @@ impl FileOpener for ParquetOpener {
                     )
                     .rewrite(p)
                     .map_err(ArrowError::from)
+                    .map(|p| {
+                        PhysicalExprSimplifier::new(&physical_file_schema)
+                            .simplify(p)
+                            .map_err(ArrowError::from)
+                    })
                 })
+                .transpose()?
                 .transpose()?;
 
             // Build predicates for this specific file