Add initial support for schema types in static typing system

[CaiJimmy]

Static typing now uses the schema types of nodes. Typed node tests (element(*, T), attribute(*, T), schema-element(E), schema-attribute(A)) know the typed value their schema type declares, and validate expressions infer the schema type they annotate their result with.

Based on #1881. It also contains the two commits of #1884 (schema type names keep their import prefix), which it needs; they will disappear from this diff once #1884 merges.

Typed values

Atomizing a node now yields the typed value its schema type declares, instead of always xs:anyAtomicType*. An instance may select a derived type with xsi:type, so the typed value covers the type and every type derived from it.

Examples from static-typing/schema-typed-values/ (types from TypedValues.xsd):

Expression	Inferred type	Why
validate { <t:price>4.5</t:price> } + 1	xs:decimal	t:Price restricts xs:decimal
data(validate { <t:amount currency="CHF">3</t:amount> })	t:Price	simple content with an attribute
data(validate { <t:optional-price .../> })	t:Price?	nillable, and a nilled element has no typed value
data(validate { <t:tags>a b</t:tags> })	xs:string*	list type
data(validate { <t:note>a<t:b>b</t:b></t:note> })	xs:untypedAtomic	mixed content
data(validate { <t:marker/> })	xs:untypedAtomic?	empty, but the derived t:Remark adds mixed content
data(validate { <t:order>...</t:order> })	xs:anyAtomicType*	element-only content has no typed value

Item types report this through ItemType.getTypedValueType() (null when unknown), which TypeAtomization and the LSP can use.

How the typed value comes from the Xerces model

XmlSchemaCatalog already mapped a Xerces simple type to a Rumble atomic type (t:Price becomes a DerivedAtomicItemType based on xs:decimal), and any type to an annotation (its name and base-type chain). This PR adds a third mapping, from a type definition to the SequenceType of its typed value, or to unknown when it is no narrower than xs:anyAtomicType*.

Simple types:

• An atomic type or pure union has exactly one value of its mapped type: t:Price gives t:Price.
• A list, or a union with a list member, gives the list's item type with *: t:Tags gives xs:string*.
• A union with constraining facets has no XDM type, so it uses the nearest base type that has one.
• xs:anySimpleType stays unknown, since its values may also be lists.

Complex types: an instance may select a derived type with xsi:type, so the typed value covers the type and every complex type derived from it, joined with leastCommonSupertypeWith:

Content type	Typed value
empty	()
mixed	xs:untypedAtomic
simple	the typed value of its simple type
element-only	none: atomization raises FOTY0012, so it adds nothing

For example t:Marker is empty, but t:Remark extends it with mixed content, so it gives () ⊔ xs:untypedAtomic = xs:untypedAtomic?. If nothing but the empty sequence remains, the typed value is unknown.

Xerces only lists named types, so the catalog collects every complex type once when it is built, including the anonymous types of global and local element declarations, and finds derived types by scanning them with derivedFromType. Typed values are cached per type definition because of that scan.

Two rules live in the node types rather than the catalog:

• ElementNodeItemType adds the empty sequence for a nillable element, since a nilled element has no typed value.
• SchemaElementNodeItemType combines the typed values of its alternatives: the declaration and the members of its substitution group.

Known approximations:

• Facets are not carried over, so t:Price is statically just a restriction of xs:decimal.
• Derived types are joined by their least common supertype, not into a union, so content types that disagree widen to xs:anyAtomicType.

Validate expressions

Expression	Inferred type
validate { <t:price>4.5</t:price> }	schema-element(t:price)
validate type t:Price { <total>4.5</total> }	element(total, t:Price)
validate lax { <t:unknown/> }	element(t:unknown) (no declaration, so not annotated)
validate { document { <s:root>1</s:root> } }	document-node(schema-element(s:root))

Strict validation requires a global declaration with the element's name (XQDY0084), so when the element's name is not known statically but the schema has a single global element declaration, that declaration is used.

Checks that use typed values

Operations that atomize their operands now check known typed values statically, and only leave nodes whose typed value is unknown to runtime:

• Function arguments: sum(validate { <t:price>4.5</t:price> }) is xs:decimal, and sum(validate { <t:tags>a b</t:tags> }) is a static error because the typed value is xs:string*.
• Casts check both the type and the cardinality of the typed value. Casting a list-typed element to a single type, or a nillable element to a non-optional type, is now a static XPTY0004; the message names the typed value, e.g. schema-element(t:tags) with typed value xs:string*.

TypeAtomization.containsNode no longer counts the error type (the type of fn:error()) as a node: it is also atomic and atomizes to itself, which made function argument checks recurse forever (K-FunctionProlog-66, xs-error-017, xs-error-019).

[github-actions]

QT3 Test Results - Parser: jsoniq

Regression baseline: run 37837493959

🎉 No regressions found for this build.

Summary of passed tests for jsoniq

Test Suite	Passing	Failing	Errors	Skipped	Missing features	Total
app	2056	27	69	5	5	2157
array	208	0	1	0	0	209
fn	10311	268	169	387	315	11135
map	220	0	0	0	0	220
math	149	0	0	0	0	149
misc	765	34	20	52	18	871
op	4351	3	12	0	0	4366
prod	11505	328	166	208	7	12207
ser	332	11	0	0	0	343
xs	155	0	0	9	0	164
Total	30052	671	437	661	345	31821

Full analysis report: see analysis-jsoniq in artifacts.

Download detailed test results

[github-actions]

QT3 Test Results - Parser: xquery

Regression baseline: run 37837493959

🎉 No regressions found for this build.

Summary of passed tests for xquery

Test Suite	Passing	Failing	Errors	Skipped	Missing features	Total
app	2063	26	63	5	5	2157
array	209	0	0	0	0	209
fn	10333	247	168	387	315	11135
map	220	0	0	0	0	220
math	149	0	0	0	0	149
misc	769	30	20	52	18	871
op	4351	3	12	0	0	4366
prod	11588	279	132	208	7	12207
ser	343	0	0	0	0	343
xs	155	0	0	9	0	164
Total	30180	585	395	661	345	31821

Full analysis report: see analysis-xquery in artifacts.

Download detailed test results