feat(kernel): preserve union nodes across extraction

src/context/index.ts

@@ -559,7 +559,7 @@ export class ContextBuilder {
         // but are almost never what exploration queries want.
         const searchKinds = opts.nodeKinds && opts.nodeKinds.length > 0
           ? opts.nodeKinds
-          : ['file', 'module', 'class', 'struct', 'interface', 'trait', 'protocol',
+          : ['file', 'module', 'class', 'struct', 'union', 'interface', 'trait', 'protocol',
              'function', 'method', 'property', 'field', 'variable', 'constant',
              'enum', 'enum_member', 'type_alias', 'namespace', 'export',
              'route', 'component'] as NodeKind[];

src/mcp/tools.ts

@@ -343,7 +343,7 @@ export function getExploreOutputBudget(fileCount: number): ExploreOutputBudget {
  */
 export const RELEVANCE_KIND_WEIGHT: Readonly<Record<string, number>> = {
   // Callables and types: the answer lives in one of these.
-  function: 1, method: 1, class: 1, struct: 1, interface: 1, trait: 1,
+  function: 1, method: 1, class: 1, struct: 1, union: 1, interface: 1, trait: 1,
   protocol: 1, component: 1, route: 1, enum: 1, type_alias: 1, constructor: 1,
   // Containers: real structure, but a whole namespace/module matching a term is
   // a coarser signal than a callable matching it.
@@ -3968,7 +3968,7 @@ export class ToolHandler {
     const superMany = new Map<string, boolean>();
     const definesPolymorphicSupertype = (nodes: Node[]): boolean => {
       for (const n of nodes) {
-        if (n.kind !== 'class' && n.kind !== 'interface' && n.kind !== 'struct'
+        if (n.kind !== 'class' && n.kind !== 'interface' && n.kind !== 'struct' && n.kind !== 'union'
             && n.kind !== 'trait' && n.kind !== 'protocol' && n.kind !== 'type_alias') continue;
         let many = superMany.get(n.id);
         if (many === undefined) {

src/resolution/c-fnptr-synthesizer.ts

@@ -703,7 +703,7 @@ export async function cFnPointerDispatchEdges(
       if (prof) { prof.nodesMs += Date.now() - tN; prof.nodesN++; }
       const structs: CfnptrFileIn['structs'] = [];
       for (const st of fileNodes) {
-        if (st.kind !== 'struct') continue;
+        if (st.kind !== 'struct' && st.kind !== 'union') continue;
         // sliceLinesPre semantics ride along: falsy startLine never parses,
         // and `endLine ?? startLine` is applied here so the kernel sees the
         // exact slice bounds the JS sweep would use.
@@ -740,7 +740,7 @@ export async function cFnPointerDispatchEdges(
     if (prof) { prof.nodesMs += Date.now() - tN; prof.nodesN++; }
     let lines: string[] | null = null;
     for (const st of fileNodes) {
-      if (st.kind !== 'struct') continue;
+      if (st.kind !== 'struct' && st.kind !== 'union') continue;
       lines ??= s.split('\n');
       const body = sliceLinesPre(lines, st.startLine, st.endLine);
       const open = body.indexOf('{');

src/resolution/import-resolver.ts

@@ -1827,6 +1827,7 @@ function resolveRustPathReference(
       n.name === leaf &&
       (n.kind === 'function' ||
         n.kind === 'struct' ||
+        n.kind === 'union' ||
         n.kind === 'enum' ||
         n.kind === 'trait' ||
         n.kind === 'type_alias' ||

src/resolution/name-matcher.ts

@@ -798,12 +798,12 @@ function lookupCalleeReturnType(
   return candidates.find((n) => n.kind === 'function')?.returnType ?? null;
 }
 
-/** Does the graph contain a class/struct named `name`'s last segment? */
+/** Does the graph contain an aggregate type named `name`'s last segment? */
 function cppClassExists(name: string, ref: UnresolvedRef, context: ResolutionContext): boolean {
   const last = cppLastSegment(name);
   return context
     .getNodesByName(last)
-    .some((n) => (n.kind === 'class' || n.kind === 'struct') && n.language === ref.language);
+    .some((n) => (n.kind === 'class' || n.kind === 'struct' || n.kind === 'union') && n.language === ref.language);
 }
 
 /**
@@ -1771,7 +1771,7 @@ export function matchMethodCall(
     );
 
     for (const classNode of classCandidates) {
-      if (classNode.kind === 'class' || classNode.kind === 'struct' || classNode.kind === 'interface') {
+      if (classNode.kind === 'class' || classNode.kind === 'struct' || classNode.kind === 'union' || classNode.kind === 'interface') {
         // Skip cross-language class matches
         if (classNode.language !== ref.language) continue;
 
@@ -1807,7 +1807,7 @@ export function matchMethodCall(
         ref.filePath,
       );
       for (const classNode of fuzzyClassCandidates) {
-        if (classNode.kind === 'class' || classNode.kind === 'struct' || classNode.kind === 'interface') {
+        if (classNode.kind === 'class' || classNode.kind === 'struct' || classNode.kind === 'union' || classNode.kind === 'interface') {
           // Skip cross-language class matches
           if (classNode.language !== ref.language) continue;
 

src/search/query-utils.ts

@@ -393,6 +393,7 @@ export function kindBonus(kind: Node['kind']): number {
     interface: 9,
     type_alias: 6,
     struct: 6,
+    union: 6,
     trait: 9,
     enum: 5,
     component: 8,