test(TypeScript): test ...infer type with parens (#9056)

prettier · Aug 26, 2020 · 77c8da7 · 77c8da7
1 parent ee57066
commit 77c8da7
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diff --git a/tests/typescript/rest-type/__snapshots__/jsfmt.spec.js.snap b/tests/typescript/rest-type/__snapshots__/jsfmt.spec.js.snap
@@ -22,13 +22,25 @@ printWidth: 80
 =====================================input======================================
 type Tail<T extends any[]> = T extends [infer U, ...infer R] ? R : never;
 
+// should remove parens from this, to avoid a type issue with TypeScript 4.0:
+type Tail2<T extends any[]> = T extends [infer U, ...(infer R)] ? R : never;
+
+// but not remove parens from this:
+type Tail3<T extends any[]> = T extends [infer U, ...(infer R)[]] ? R : never;
+
 type ReduceNextElement<
   T extends readonly unknown[]
 > = T extends readonly [infer V, ...infer R] ? [V, R] : never
 
 =====================================output=====================================
 type Tail<T extends any[]> = T extends [infer U, ...infer R] ? R : never;
 
+// should remove parens from this, to avoid a type issue with TypeScript 4.0:
+type Tail2<T extends any[]> = T extends [infer U, ...infer R] ? R : never;
+
+// but not remove parens from this:
+type Tail3<T extends any[]> = T extends [infer U, ...(infer R)[]] ? R : never;
+
 type ReduceNextElement<T extends readonly unknown[]> = T extends readonly [
   infer V,
   ...infer R

diff --git a/tests/typescript/rest-type/infer-type.ts b/tests/typescript/rest-type/infer-type.ts
@@ -1,5 +1,11 @@
 type Tail<T extends any[]> = T extends [infer U, ...infer R] ? R : never;
 
+// should remove parens from this, to avoid a type issue with TypeScript 4.0:
+type Tail2<T extends any[]> = T extends [infer U, ...(infer R)] ? R : never;
+
+// but not remove parens from this:
+type Tail3<T extends any[]> = T extends [infer U, ...(infer R)[]] ? R : never;
+
 type ReduceNextElement<
   T extends readonly unknown[]
 > = T extends readonly [infer V, ...infer R] ? [V, R] : never