Update array/tuple relationship checking

ahejlsberg · ahejlsberg · commit db840f41c553 · 2019-01-15T14:44:38.000-08:00
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -12622,7 +12622,7 @@ namespace ts {
                             errorInfo = saveErrorInfo;
                         }
                     }
-                    else if (isTupleType(source) && isArrayType(target) || isArrayType(source) && isReadonlyArrayType(target)) {
+                    else if (isReadonlyArrayType(target) ? isArrayType(source) || isTupleType(source) : isArrayType(target) && isTupleType(source) && !source.target.readonly) {
                         return isRelatedTo(getIndexTypeOfType(source, IndexKind.Number) || anyType, getIndexTypeOfType(target, IndexKind.Number) || anyType, reportErrors);
                     }
                     // Even if relationship doesn't hold for unions, intersections, or generic type references,

Original file line number	Diff line number	Diff line change
`@@ -12622,7 +12622,7 @@ namespace ts {`
`12622`	`12622`	`errorInfo = saveErrorInfo;`
`12623`	`12623`	`}`
`12624`	`12624`	`}`
`12625`		`- else if (isTupleType(source) && isArrayType(target) \|\| isArrayType(source) && isReadonlyArrayType(target)) {`
	`12625`	`+ else if (isReadonlyArrayType(target) ? isArrayType(source) \|\| isTupleType(source) : isArrayType(target) && isTupleType(source) && !source.target.readonly) {`
`12626`	`12626`	`return isRelatedTo(getIndexTypeOfType(source, IndexKind.Number) \|\| anyType, getIndexTypeOfType(target, IndexKind.Number) \|\| anyType, reportErrors);`
`12627`	`12627`	`}`
`12628`	`12628`	`// Even if relationship doesn't hold for unions, intersections, or generic type references,`