Make Soy cast a no-op in JBCSRC.

PiperOrigin-RevId: 785456760

Author: Jesse-Good

java/src/com/google/template/soy/jbcsrc/ExpressionCompiler.java

@@ -526,10 +526,8 @@ protected SoyExpression visitBooleanNode(BooleanNode node) {
 
     @Override
     protected SoyExpression visitAsOpNode(AsOpNode node) {
-      // Casting requires boxing since the JVM can't just cast one primitive to another without
-      // coercing (and thus changing the underlying value).
-      SoyExpression value = visit(node.getChild(0)).box();
-      return SoyExpression.forSoyValue(node.getType(), value.checkedSoyCast(node.getType()));
+      // Casting is a compiler / type checking construct.
+      return visit(node.getChild(0));
     }
 
     @Override
@@ -1605,7 +1603,7 @@ private SoyExpression visitItemAccess(SoyExpression baseExpr, ItemAccessNode nod
       // Special case index lookups on lists to avoid boxing the int key.  Maps cannot be
       // optimized the same way because there is no real way to 'unbox' a SoyLegacyObjectMap.
       if (baseExpr.soyRuntimeType().isKnownListOrUnionOfLists()) {
-        SoyExpression list = baseExpr.unboxAsListUnchecked();
+        Expression list = baseExpr.unboxAsListUnchecked();
         SoyExpression index = keyExpr.coerceToIndex();
         if (analysis.isResolved(node)) {
           soyValueProvider = MethodRefs.RUNTIME_GET_LIST_ITEM.invoke(list, index);

java/src/com/google/template/soy/jbcsrc/ExternCompiler.java

@@ -483,7 +483,7 @@ private static Expression adaptParameter(
     if (!isObject
         && BytecodeUtils.isDefinitelyAssignableFrom(javaType, BytecodeUtils.IMMUTABLE_LIST_TYPE)) {
       SoyType elmType = SoyTypes.getIterableElementType(nonNullableSoyType);
-      SoyExpression unboxedList =
+      Expression unboxedList =
           actualParam.isBoxed() ? actualParam.unboxAsListOrJavaNull() : actualParam;
       switch (elmType.getKind()) {
         case INT:

java/src/com/google/template/soy/jbcsrc/ProtoUtils.java

@@ -102,6 +102,7 @@
 import com.google.template.soy.types.SoyType;
 import com.google.template.soy.types.SoyTypes;
 import com.google.template.soy.types.UnionType;
+import com.google.template.soy.types.UnknownType;
 import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.LinkedHashMap;
@@ -1285,7 +1286,7 @@ private Statement handleRepeatedNotNull(SoyExpression listArg, FieldDescriptor f
       checkArgument(listArg.isNonSoyNullish());
 
       // Unbox listArg as List<SoyValueProvider> and wait until all items are done
-      SoyExpression unboxed = listArg.unboxAsListUnchecked();
+      Expression unboxed = listArg.unboxAsListUnchecked();
       Expression resolved = detacher.resolveSoyValueProviderList(unboxed);
 
       // Enter new scope
@@ -1304,7 +1305,10 @@ private Statement handleRepeatedNotNull(SoyExpression listArg, FieldDescriptor f
       // exitScope must be called after creating all the variables
       Label scopeExit = scope.exitScopeMarker();
       // Expected type info of the list element
-      SoyType elementSoyType = unboxed.soyType().asType(ListType.class).getElementType();
+      SoyType elementSoyType =
+          listArg.soyType() instanceof ListType
+              ? listArg.soyType().asType(ListType.class).getElementType()
+              : UnknownType.getInstance();
       SoyRuntimeType elementType = SoyRuntimeType.getBoxedType(elementSoyType);
 
       // Call list.get(i).resolveSoyValueProvider(), then cast to the expected subtype of SoyValue

java/src/com/google/template/soy/jbcsrc/restricted/SoyExpression.java

@@ -59,7 +59,6 @@
 import com.google.template.soy.types.SoyTypes;
 import com.google.template.soy.types.StringType;
 import com.google.template.soy.types.UndefinedType;
-import com.google.template.soy.types.UnknownType;
 import java.math.BigInteger;
 import java.util.Iterator;
 import java.util.List;
@@ -793,7 +792,7 @@ public Expression unboxAsIteratorUnchecked() {
   }
 
   /** Unboxes a list and its items. Throws an exception if the boxed list value is nullish. */
-  public SoyExpression unboxAsListUnchecked() {
+  public Expression unboxAsListUnchecked() {
     return this.asNonSoyNullish().unboxAsListOrJavaNull();
   }
 
@@ -802,33 +801,16 @@ public SoyExpression unboxAsListUnchecked() {
    * parameter for an extern or plugin implementation, which both expect Java null rather than
    * NullData or UndefinedData.
    */
-  public SoyExpression unboxAsListOrJavaNull() {
+  public Expression unboxAsListOrJavaNull() {
     if (alreadyUnboxed(List.class)) {
       return this;
     }
     assertBoxed(List.class);
-    var delegate = delegateWithoutCast();
-    Expression unboxedList =
-        delegate.invoke(
+    return delegateWithoutCast()
+        .invoke(
             delegate.isNonSoyNullish()
                 ? MethodRefs.SOY_VALUE_AS_JAVA_LIST
                 : MethodRefs.SOY_VALUE_AS_JAVA_LIST_OR_NULL);
-
-    ListType asListType;
-    SoyRuntimeType nonNullRuntimeType =
-        SoyRuntimeType.getBoxedType(SoyTypes.excludeNullish(soyType()));
-    if (!SoyTypes.isNullOrUndefined(soyType()) && nonNullRuntimeType.isKnownIterable()) {
-      asListType = nonNullRuntimeType.asListType();
-    } else {
-      if (soyType().isEffectivelyEqual(UnknownType.getInstance())
-          || SoyTypes.isNullOrUndefined(soyType())) {
-        asListType = ListType.of(UnknownType.getInstance());
-      } else {
-        // The type checker should have already rejected all of these
-        throw new UnsupportedOperationException("Can't convert " + soyRuntimeType + " to List");
-      }
-    }
-    return forList(asListType, unboxedList);
   }
 
   /** Unboxes a proto message. Throws an exception if the boxed value is nullish. */