DFSPostOrder performs an iterative post-order depth-first search, yielding (index, data) pairs. Children are emitted before their parents. Neighbors a

DiscoverTestCases finds all .ts test files in the test cases directory for the given version.

EnterCommandLineMode sets the CLI mode flag to true and returns a restore function that reverts it to its previous value. Intended for use with defer:

ExtendsContextService checks if a class declaration extends Context.Service<Self, Shape>()(key). It detects the double-call pattern: class X extends

GetTypeAtLocation returns the checker type for node using the parser's safety guards.

IsAcyclic returns true if the graph contains no cycles. Uses iterative DFS with recursion stack tracking to detect back edges.

IsLayerType returns true if the type has the Layer variance struct.

NeighborsDirected returns the neighbor node indices reachable via edges in the given direction. For Outgoing, returns target nodes. For Incoming, retu

NewFixTransformer creates a FixTransformer from the given resolved Effect options. Returns nil if the preferences are empty (no packages configured).

ParseAccessedExpressionForCompletion finds the accessed expression at the given cursor position. It handles three cases: - extends Schema.Tag| — curso

StreamType parses a Stream type and extracts A, E, R parameters. For v3, Stream carries the Effect variance struct, so this delegates to EffectType.

ToCategory converts a Severity to the corresponding diagnostics.Category for diagnostic reporting. This function stays here because etscore cannot imp

* Create a ChangeTracker context

findAsyncFunction walks the ancestor chain from token to find the nearest async function declaration, function expression, or arrow function.

findParentOfKind walks up the parent chain to find a node of the given kind.

formatLocation returns a human-readable location string for a node. If the node is in the same source file as fromSourceFile, returns "ln {line} col {

getNodeText returns the trimmed source text of a node.

getTypeDisplayName returns the string representation of a type with no truncation.

isPrimitiveType checks if a type (or any member of a union type) is a primitive type.

mermaidSafe encodes a string for use in Mermaid subgraph headers (nested format). It normalizes whitespace, truncates, and encodes only quotes and ang

removeFromSlice removes the first occurrence of val from slice.

transformBodyAwaitToYield replaces all AwaitExpression nodes in the body with the result of onAwait. Returns a deep-cloned, fully synthetic tree.

AnalyzeUnnecessaryEffectGen finds all Effect.gen calls that contain only a single yield* statement and can be replaced with the yielded expression dir

AppendToUniqueTypesMap deduplicates types using bidirectional assignability checks. It unrolls union types, skips excluded types (via shouldExclude),

CreateString computes the expected key string for a class declaration. It takes the source file name, package name, package directory, class name, and

DiscoverPackages iterates all source files in the program, resolves each one's nearest package.json, and returns a deduplicated list of discovered pac

EffectSchemaTypes extracts the A (Type) and E (Encoded) types from a Schema type. Returns nil if the type is not a recognized Schema type or types can

ExtendsEffectTag checks if a class declaration extends Effect.Tag("key")<Self, Shape>(). It detects the pattern: class X extends Effect.Tag("key")<X

ExtendsSchemaTaggedError checks if a class declaration extends Schema.TaggedError<T>("identifier")("tag", { ... }).

GetEffectiveSeverityAndMarkUsed returns the effective severity and marks the directive as used if it affected the result. This is used to track unused

GetFunctionLikeName returns the name string from a function-like node. Handles FunctionDeclaration, FunctionExpression, MethodDeclaration (with identi

GetFunctionLikeParameters returns the parameters NodeList from a function-like node. Handles ArrowFunction, FunctionExpression, FunctionDeclaration, a

GetFunctionLikeTypeParameters returns the type parameters NodeList from a function-like node. Handles ArrowFunction, FunctionExpression, FunctionDecla

GetMermaidBaseURL resolves the MermaidProvider value to a full base URL. - "" or "mermaid.live" → "https://mermaid.live/edit#" - "mermaid.com" → "http

GetPipeableMinArgCount returns the configured minimum pipeable arg count, or 2 if not set.

GetUnusedNextLineDirectives returns next-line directives that did not suppress any diagnostic. This is used to report unusedDirective warnings.

HasEnablingDirective returns true if any file-level section directive or next-line directive enables the given rule (i.e., sets it to a non-off, non-s

IsContextTag returns true if the type has the Context.Tag variance struct.

IsNodeReferenceToEffectPackageExport reports whether node resolves to a member exported by any module in the "effect" npm package. Unlike IsNodeRefere

RemoveEdge removes the edge at the given index.

ResolveDiagnosticSeverityForFile resolves ordered diagnostic severity overrides for a file.

* Apply text changes to original text and return the result

collectChildIndices gathers graph node indices for the given AST nodes, filtering out nodes that aren't in the graph.

createOpaqueInterface creates: export interface <name> extends <heritage> { }

dfsPostOrderWithOrder performs an iterative post-order DFS with custom node ordering. Neighbors are sorted by provides count descending, then requires

extendsSchemaTagged checks if a class declaration extends Schema.<memberName> with the double-call pattern: class X extends Schema.TaggedClass<X>("i

extractContravariantType gets the type argument from a contravariant property. Contravariant<A> is encoded as (_: A) => void, so we get the first para

extractNodeText gets the source text of a node, skipping leading trivia.

findInterfaceOrTypeAlias walks the ancestor chain from the token at the cursor to find an InterfaceDeclaration or TypeAliasDeclaration whose name over

findSingleReturnExpression finds the expression from a single return statement in a block.

* Get the root object literal from a JSON source file

inferNamespaceName derives a namespace name from the last segment of a module specifier path. For example, "effect/Effect" → "Effect", "effect" → "eff

layerServiceNameFromExpression resolves an expression to a service name string. When the expression is the `this` keyword, it walks up the AST to find

* Helper to create a minimal Assessment.State for testing

parseAllLiterals tries to parse a type node as a collection of literal values. Returns (literals, true) on success, (nil, false) if the node contains

parseJsonMethod checks if a call expression is JSON.parse or JSON.stringify. Returns the call expression node if it matches, nil otherwise.

parseVarianceStruct extracts A, E, R from a variance struct type.

prepareTestFS detects Effect imports or explicit version markers in test files and mounts real Effect packages into the fourslash VFS.

processMembers handles property signatures and index signatures from type members.

resolveTraversalConfig returns the start nodes and direction for a traversal, applying defaults when the config fields are empty.