Exclude method symbols when relating tuple types

ahejlsberg · ahejlsberg · commit 842c588f3ef5 · 2019-08-28T07:52:42.000-04:00
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -14123,9 +14123,11 @@ namespace ts {
                 // We only call this for union target types when we're attempting to do excess property checking - in those cases, we want to get _all possible props_
                 // from the target union, across all members
                 const properties = target.flags & TypeFlags.Union ? getPossiblePropertiesOfUnionType(target as UnionType) : getPropertiesOfType(target);
+                const numericNamesOnly = isTupleType(source) && isTupleType(target);
                 for (const targetProp of excludeProperties(properties, excludedProperties)) {
-                    if (!(targetProp.flags & SymbolFlags.Prototype)) {
-                        const sourceProp = getPropertyOfType(source, targetProp.escapedName);
+                    const name = targetProp.escapedName;
+                    if (!(targetProp.flags & SymbolFlags.Prototype) && (!numericNamesOnly || isNumericLiteralName(name) || name === "length")) {
+                        const sourceProp = getPropertyOfType(source, name);
                         if (sourceProp && sourceProp !== targetProp) {
                             const related = propertyRelatedTo(source, target, sourceProp, targetProp, getTypeOfSymbol, reportErrors, isIntersectionConstituent);
                             if (!related) {
