Function normalize_field_access_after_subscript 

fn normalize_field_access_after_subscript(
    stmt: &mut Statement,
    normalize_ident: bool,
)

Normalizes dot field accesses that follow a subscript for DataFusion.

sqlparser represents j.o.l[1].inner.l[2] as a compound field access with the following access chain:

Dot(Identifier("o")),
Dot(Identifier("l")),
Subscript(1),
Dot(Identifier("inner")),
Dot(Identifier("l")),
Subscript(2)

DataFusion first resolves the leading j.o.l through JsonExprPlanner::plan_compound_identifier, which produces an untyped json_get with path o.l. Before invoking JsonExprPlanner::plan_field_access, however, DataFusion eagerly converts every remaining access into a GetFieldAccess. It accepts string values but not [SqlExpr::Identifier]s in [AccessExpr::Dot] after a subscript. Without this normalization, that conversion fails at .inner, and plan_field_access is never called, even for the preceding [1].

This function converts dot identifiers after the first subscript into Dot(Value(SingleQuotedString(...))), applying DataFusion’s identifier normalization before discarding whether each identifier was quoted. It changes neither the SQL text nor the dot accesses into subscript nodes: the resulting AST is conceptually j.o.l[1].'inner'.'l'[2]. DataFusion converts the string-valued dot accesses into named field accesses, which plan_field_access safely encodes as bracket members. It can then extend the JSON path to o.l[1]["inner"]["l"][2].

This behavior is unchanged in the latest upstream releases checked here: DataFusion 55.0.0 and sqlparser 0.62.0.

TODO(LFC): Remove this workaround after upstream supports dot identifiers after subscripts.