Update LKG

Author: typescript-bot

lib/tsc.js

@@ -55344,12 +55344,10 @@ function createTypeChecker(host) {
     const target = type.target ?? type;
     const typeVariable = getHomomorphicTypeVariable(target);
     if (typeVariable && !target.declaration.nameType) {
-      const constraint = getConstraintTypeFromMappedType(type);
-      if (constraint.flags & 4194304 /* Index */) {
-        const baseConstraint = getBaseConstraintOfType(constraint.type);
-        if (baseConstraint && everyType(baseConstraint, (t) => isArrayOrTupleType(t) || isArrayOrTupleOrIntersection(t))) {
-          return instantiateType(target, prependTypeMapping(typeVariable, baseConstraint, type.mapper));
-        }
+      const modifiersType = getModifiersTypeFromMappedType(type);
+      const baseConstraint = isGenericMappedType(modifiersType) ? getApparentTypeOfMappedType(modifiersType) : getBaseConstraintOfType(modifiersType);
+      if (baseConstraint && everyType(baseConstraint, (t) => isArrayOrTupleType(t) || isArrayOrTupleOrIntersection(t))) {
+        return instantiateType(target, prependTypeMapping(typeVariable, baseConstraint, type.mapper));
       }
     }
     return type;

lib/tsserver.js

@@ -60088,12 +60088,10 @@ function createTypeChecker(host) {
     const target = type.target ?? type;
     const typeVariable = getHomomorphicTypeVariable(target);
     if (typeVariable && !target.declaration.nameType) {
-      const constraint = getConstraintTypeFromMappedType(type);
-      if (constraint.flags & 4194304 /* Index */) {
-        const baseConstraint = getBaseConstraintOfType(constraint.type);
-        if (baseConstraint && everyType(baseConstraint, (t) => isArrayOrTupleType(t) || isArrayOrTupleOrIntersection(t))) {
-          return instantiateType(target, prependTypeMapping(typeVariable, baseConstraint, type.mapper));
-        }
+      const modifiersType = getModifiersTypeFromMappedType(type);
+      const baseConstraint = isGenericMappedType(modifiersType) ? getApparentTypeOfMappedType(modifiersType) : getBaseConstraintOfType(modifiersType);
+      if (baseConstraint && everyType(baseConstraint, (t) => isArrayOrTupleType(t) || isArrayOrTupleOrIntersection(t))) {
+        return instantiateType(target, prependTypeMapping(typeVariable, baseConstraint, type.mapper));
       }
     }
     return type;

lib/typescript.js

@@ -57843,12 +57843,10 @@ ${lanes.join("\n")}
       const target = type.target ?? type;
       const typeVariable = getHomomorphicTypeVariable(target);
       if (typeVariable && !target.declaration.nameType) {
-        const constraint = getConstraintTypeFromMappedType(type);
-        if (constraint.flags & 4194304 /* Index */) {
-          const baseConstraint = getBaseConstraintOfType(constraint.type);
-          if (baseConstraint && everyType(baseConstraint, (t) => isArrayOrTupleType(t) || isArrayOrTupleOrIntersection(t))) {
-            return instantiateType(target, prependTypeMapping(typeVariable, baseConstraint, type.mapper));
-          }
+        const modifiersType = getModifiersTypeFromMappedType(type);
+        const baseConstraint = isGenericMappedType(modifiersType) ? getApparentTypeOfMappedType(modifiersType) : getBaseConstraintOfType(modifiersType);
+        if (baseConstraint && everyType(baseConstraint, (t) => isArrayOrTupleType(t) || isArrayOrTupleOrIntersection(t))) {
+          return instantiateType(target, prependTypeMapping(typeVariable, baseConstraint, type.mapper));
         }
       }
       return type;