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Bound recursive array and tuple type printing #64694

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Copilot Oct 8, 2026
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Bound recursive array and tuple type printing
Copilot Oct 8, 2026
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9 changes: 9 additions & 0 deletions tsc/internal/checker/nodebuilderimpl.go
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Expand Up @@ -81,6 +81,7 @@ type NodeBuilderContext struct {
inferTypeParameters []*Type
visitedTypes collections.Set[TypeId]
symbolDepth map[CompositeSymbolIdentity]int
containerDepth int
trackedSymbols []*TrackedSymbolArgs
mapper *TypeMapper
reverseMappedStack []*ast.Symbol
Expand Down Expand Up @@ -3245,6 +3246,14 @@ func (b *NodeBuilderImpl) visitAndTransformType(t *Type, transform func(b *NodeB
if b.ctx.visitedTypes.Has(typeId) {
return b.createCyclicStructurePlaceholder()
}
if isArrayOrTuple {
if b.ctx.containerDepth >= 20 {
b.ctx.truncating = true
return b.createElidedInformationPlaceholder()
}
b.ctx.containerDepth++
defer func() { b.ctx.containerDepth-- }()
}

isConstructorObject := t.objectFlags&ObjectFlagsAnonymous != 0 && t.symbol != nil && t.symbol.Flags&ast.SymbolFlagsClass != 0
var id *CompositeSymbolIdentity
Expand Down
10 changes: 10 additions & 0 deletions tsc/testdata/baselines/reference/compiler/recursiveArrayTupleDeclarationEmit.errors.txt
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recursiveArrayTupleDeclarationEmit.ts(3,14): error TS7056: The inferred type of this node exceeds the maximum length the compiler will serialize. An explicit type annotation is needed.


==== recursiveArrayTupleDeclarationEmit.ts (1 errors) ====
type G<T> = T extends unknown ? (T | G<[T]>)[] : never;
declare const g: G<"x">;
export const h = g;
~
!!! error TS7056: The inferred type of this node exceeds the maximum length the compiler will serialize. An explicit type annotation is needed.

10 changes: 10 additions & 0 deletions tsc/testdata/baselines/reference/compiler/recursiveArrayTupleDeclarationEmit.js
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//// [tests/cases/compiler/recursiveArrayTupleDeclarationEmit.ts] ////

//// [recursiveArrayTupleDeclarationEmit.ts]
type G<T> = T extends unknown ? (T | G<[T]>)[] : never;
declare const g: G<"x">;
export const h = g;


//// [recursiveArrayTupleDeclarationEmit.js]
export const h = g;
19 changes: 19 additions & 0 deletions tsc/testdata/baselines/reference/compiler/recursiveArrayTupleDeclarationEmit.symbols
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//// [tests/cases/compiler/recursiveArrayTupleDeclarationEmit.ts] ////

=== recursiveArrayTupleDeclarationEmit.ts ===
type G<T> = T extends unknown ? (T | G<[T]>)[] : never;
>G : Symbol(G, Decl(recursiveArrayTupleDeclarationEmit.ts, 0, 0))
>T : Symbol(T, Decl(recursiveArrayTupleDeclarationEmit.ts, 0, 7))
>T : Symbol(T, Decl(recursiveArrayTupleDeclarationEmit.ts, 0, 7))
>T : Symbol(T, Decl(recursiveArrayTupleDeclarationEmit.ts, 0, 7))
>G : Symbol(G, Decl(recursiveArrayTupleDeclarationEmit.ts, 0, 0))
>T : Symbol(T, Decl(recursiveArrayTupleDeclarationEmit.ts, 0, 7))

declare const g: G<"x">;
>g : Symbol(g, Decl(recursiveArrayTupleDeclarationEmit.ts, 1, 13))
>G : Symbol(G, Decl(recursiveArrayTupleDeclarationEmit.ts, 0, 0))

export const h = g;
>h : Symbol(h, Decl(recursiveArrayTupleDeclarationEmit.ts, 2, 12))
>g : Symbol(g, Decl(recursiveArrayTupleDeclarationEmit.ts, 1, 13))

13 changes: 13 additions & 0 deletions tsc/testdata/baselines/reference/compiler/recursiveArrayTupleDeclarationEmit.types
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//// [tests/cases/compiler/recursiveArrayTupleDeclarationEmit.ts] ////

=== recursiveArrayTupleDeclarationEmit.ts ===
type G<T> = T extends unknown ? (T | G<[T]>)[] : never;
>G : G<T>

declare const g: G<"x">;
>g : ("x" | (((((((((((((((((((any | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[])[]

export const h = g;
>h : ("x" | (((((((((((((((((((any | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[])[]
>g : ("x" | (((((((((((((((((((any | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[])[]

14 changes: 14 additions & 0 deletions tsc/testdata/baselines/reference/compiler/recursiveArrayTupleTypePrinting.errors.txt
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recursiveArrayTupleTypePrinting.ts(3,14): error TS2322: Type '("x" | (((((((((((((((((((any | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[])[]' is not assignable to type 'number'.
recursiveArrayTupleTypePrinting.ts(4,14): error TS2322: Type 'string' is not assignable to type 'number'.


==== recursiveArrayTupleTypePrinting.ts (2 errors) ====
type G<T> = T extends unknown ? (T | G<[T]>)[] : never;
declare const g: G<"x">;
export const n: number = g;
~
!!! error TS2322: Type '("x" | (((((((((((((((((((any | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[])[]' is not assignable to type 'number'.
export const later: number = "oops";
~~~~~
!!! error TS2322: Type 'string' is not assignable to type 'number'.

22 changes: 22 additions & 0 deletions tsc/testdata/baselines/reference/compiler/recursiveArrayTupleTypePrinting.symbols
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//// [tests/cases/compiler/recursiveArrayTupleTypePrinting.ts] ////

=== recursiveArrayTupleTypePrinting.ts ===
type G<T> = T extends unknown ? (T | G<[T]>)[] : never;
>G : Symbol(G, Decl(recursiveArrayTupleTypePrinting.ts, 0, 0))
>T : Symbol(T, Decl(recursiveArrayTupleTypePrinting.ts, 0, 7))
>T : Symbol(T, Decl(recursiveArrayTupleTypePrinting.ts, 0, 7))
>T : Symbol(T, Decl(recursiveArrayTupleTypePrinting.ts, 0, 7))
>G : Symbol(G, Decl(recursiveArrayTupleTypePrinting.ts, 0, 0))
>T : Symbol(T, Decl(recursiveArrayTupleTypePrinting.ts, 0, 7))

declare const g: G<"x">;
>g : Symbol(g, Decl(recursiveArrayTupleTypePrinting.ts, 1, 13))
>G : Symbol(G, Decl(recursiveArrayTupleTypePrinting.ts, 0, 0))

export const n: number = g;
>n : Symbol(n, Decl(recursiveArrayTupleTypePrinting.ts, 2, 12))
>g : Symbol(g, Decl(recursiveArrayTupleTypePrinting.ts, 1, 13))

export const later: number = "oops";
>later : Symbol(later, Decl(recursiveArrayTupleTypePrinting.ts, 3, 12))

17 changes: 17 additions & 0 deletions tsc/testdata/baselines/reference/compiler/recursiveArrayTupleTypePrinting.types
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//// [tests/cases/compiler/recursiveArrayTupleTypePrinting.ts] ////

=== recursiveArrayTupleTypePrinting.ts ===
type G<T> = T extends unknown ? (T | G<[T]>)[] : never;
>G : G<T>

declare const g: G<"x">;
>g : ("x" | (((((((((((((((((((any | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[])[]

export const n: number = g;
>n : number
>g : ("x" | (((((((((((((((((((any | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[] | any)[])[]

export const later: number = "oops";
>later : number
>"oops" : "oops"

6 changes: 6 additions & 0 deletions tsc/testdata/tests/cases/compiler/recursiveArrayTupleDeclarationEmit.ts
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// @strict: true
// @declaration: true

type G<T> = T extends unknown ? (T | G<[T]>)[] : never;
declare const g: G<"x">;
export const h = g;
8 changes: 8 additions & 0 deletions tsc/testdata/tests/cases/compiler/recursiveArrayTupleTypePrinting.ts
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// @strict: true
// @noErrorTruncation: true
// @noEmit: true

type G<T> = T extends unknown ? (T | G<[T]>)[] : never;
declare const g: G<"x">;
export const n: number = g;
export const later: number = "oops";
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