Module infer 

AST-based type inference for Plotnik queries.

Analyzes query AST to determine output types. Rules follow ADR-0009 (Type System).

Design

Unlike graph-based inference which must reconstruct structure from CFG traversal, AST-based inference directly walks the tree structure:

• Sequences → SeqExpr
• Alternations → AltExpr with .kind() for tagged/untagged
• Quantifiers → QuantifiedExpr
• Captures → CapturedExpr

This eliminates dry-run traversal, reconvergence detection, and scope stack management.

Structs

InferredMember

A field (for Record) or variant (for Enum).

InferredTypeDef

An inferred type definition.

TypeInferenceResult

Result of type inference.

UnificationError

Error when types cannot be unified in alternation branches.

Enums

TypeDescription

Human-readable type description for error messages.