Add BigInt support into language_in/out=ES_2020

PiperOrigin-RevId: 325250553

Author: JohnLuck77

src/com/google/javascript/jscomp/ReportBigIntLiteralTranspilationUnsupported.java

@@ -39,7 +39,7 @@ private static class ReportErrorForBigIntLiterals extends AbstractPostOrderCallb
     @Override
     public void visit(NodeTraversal t, Node n, Node parent) {
       if (n.isBigInt()) {
-        // Transpilation of BigInt is not yet supported
+        // Transpilation of BigInt is not supported
         t.report(n, BIGINT_TRANSPILATION);
       }
     }

src/com/google/javascript/jscomp/TranspilationPasses.java

@@ -23,7 +23,6 @@
 import static com.google.javascript.jscomp.parsing.parser.FeatureSet.ES8;
 import static com.google.javascript.jscomp.parsing.parser.FeatureSet.ES_NEXT;
 import static com.google.javascript.jscomp.parsing.parser.FeatureSet.ES_NEXT_IN;
-import static com.google.javascript.jscomp.parsing.parser.FeatureSet.ES_UNSUPPORTED;
 
 import com.google.javascript.jscomp.Es6RewriteDestructuring.ObjectDestructuringRewriteMode;
 import com.google.javascript.jscomp.NodeTraversal.Callback;
@@ -78,10 +77,6 @@ public static void addPostCheckTranspilationPasses(
       List<PassFactory> passes, CompilerOptions options) {
     // Note that, for features >ES8 we detect feature by feature rather than by yearly languages
     // in order to handle FeatureSet.BROWSER_2020, which is ES2019 without the new RegExp features.
-    if (options.needsTranspilationOf(Feature.BIGINT)) {
-      passes.add(reportBigIntLiteralTranspilationUnsupported);
-    }
-
     if (options.needsTranspilationOf(Feature.NUMERIC_SEPARATOR)) {
       // Numeric separators are flagged as present by the parser,
       // but never actually represented in the AST.
@@ -94,6 +89,10 @@ public static void addPostCheckTranspilationPasses(
       passes.add(rewriteOptionalChainingOperator);
     }
 
+    if (options.needsTranspilationOf(Feature.BIGINT)) {
+      passes.add(reportBigIntLiteralTranspilationUnsupported);
+    }
+
     if (options.needsTranspilationOf(Feature.NULL_COALESCE_OP)) {
       passes.add(rewriteNullishCoalesceOperator);
     }
@@ -242,9 +241,9 @@ public static void addRewritePolyfillPass(List<PassFactory> passes) {
 
   private static final PassFactory reportBigIntLiteralTranspilationUnsupported =
       PassFactory.builderForHotSwap()
-          .setName("reportBigIntTranspilation")
+          .setName("reportBigIntTranspilationUnsupported")
           .setInternalFactory(ReportBigIntLiteralTranspilationUnsupported::new)
-          .setFeatureSet(ES_UNSUPPORTED)
+          .setFeatureSet(ES2020)
           .build();
 
   private static final PassFactory rewriteExponentialOperator =

src/com/google/javascript/jscomp/parsing/parser/FeatureSet.java

@@ -203,7 +203,7 @@ public enum Feature {
     DYNAMIC_IMPORT("Dynamic module import", LangVersion.ES_UNSUPPORTED),
 
     // ES 2020 Stage 4
-    BIGINT("bigint", LangVersion.ES_UNSUPPORTED),
+    BIGINT("bigint", LangVersion.ES2020),
     IMPORT_META("import.meta", LangVersion.ES2020),
     NULL_COALESCE_OP("Nullish coalescing", LangVersion.ES2020),
     // Optional chaining is part of the ES_2020 spec, but until we can support it in output code,

test/com/google/javascript/jscomp/ReportBigIntLiteralTranspilationUnsupportedTest.java

@@ -41,7 +41,7 @@ protected CompilerPass getProcessor(Compiler compiler) {
   @Override
   protected CompilerOptions getOptions() {
     CompilerOptions options = super.getOptions();
-    options.setLanguageIn(LanguageMode.UNSUPPORTED);
+    options.setLanguageIn(LanguageMode.ECMASCRIPT_2020);
     options.setLanguageOut(LanguageMode.ECMASCRIPT5);
     return options;
   }

test/com/google/javascript/jscomp/integration/AdvancedOptimizationsIntegrationTest.java

@@ -191,7 +191,42 @@ public void testBigInt() {
     // Confirm that the native BigInt type has been implemented, so the BigInt externs don't cause
     // errors.
     externs = ImmutableList.of(new TestExternsBuilder().addBigInt().buildExternsFile("externs.js"));
-    test(options, "BigInt(1)", "BigInt(1)");
+    testSame(options, "BigInt(1)");
+  }
+
+  @Test
+  public void testFunctionThatAcceptsAndReturnsBigInt() {
+    CompilerOptions options = createCompilerOptions();
+    CompilationLevel.ADVANCED_OPTIMIZATIONS.setOptionsForCompilationLevel(options);
+    options.setLanguage(LanguageMode.ECMASCRIPT_NEXT);
+    externs =
+        ImmutableList.of(
+            new TestExternsBuilder().addBigInt().addConsole().buildExternsFile("externs.js"));
+    test(
+        options,
+        lines(
+            "/**",
+            " * @param {bigint} value",
+            " * @return {bigint}",
+            " */",
+            "function bigintTimes3(value){",
+            "  return value * 3n;",
+            "}",
+            "console.log(bigintTimes3(5n));"),
+        // TODO(b/140132715): This test should expect console.log(15n), must update
+        // PeepholeFoldConstants for this to work as intended
+        "console.log(5n * 3n);");
+  }
+
+  @Test
+  public void testBigIntStringConcatenation() {
+    CompilerOptions options = createCompilerOptions();
+    CompilationLevel.ADVANCED_OPTIMIZATIONS.setOptionsForCompilationLevel(options);
+    options.setLanguage(LanguageMode.ECMASCRIPT_NEXT);
+    externs = ImmutableList.of(new TestExternsBuilder().addBigInt().buildExternsFile("externs.js"));
+    // TODO(b/140132715): This test should expect "1nasdf", must update PeepholeFoldConstants
+    // for this to work as intended
+    test(options, "1n + 'asdf'", "1n + 'asdf'");
   }
 
   @Test

test/com/google/javascript/jscomp/parsing/ParserTest.java

@@ -3901,7 +3901,6 @@ public void testExponentialLiterals() {
 
   @Test
   public void testBigIntLiteralZero() {
-    mode = LanguageMode.UNSUPPORTED;
     Node bigint =
         parse("0n;") // SCRIPT
             .getOnlyChild() // EXPR_RESULT
@@ -3915,7 +3914,6 @@ public void testBigIntLiteralZero() {
 
   @Test
   public void testBigIntLiteralPositive() {
-    mode = LanguageMode.UNSUPPORTED;
     Node bigint =
         parse("1n;") // SCRIPT
             .getOnlyChild() // EXPR_RESULT
@@ -3929,7 +3927,6 @@ public void testBigIntLiteralPositive() {
 
   @Test
   public void testBigIntLiteralNegative() {
-    mode = LanguageMode.UNSUPPORTED;
     Node bigint =
         parse("-1n;") // SCRIPT
             .getOnlyChild() // EXPR_RESULT
@@ -3943,7 +3940,6 @@ public void testBigIntLiteralNegative() {
 
   @Test
   public void testBigIntLiteralBinary() {
-    mode = LanguageMode.UNSUPPORTED;
     Node bigint =
         parse("0b10000n;") // SCRIPT
             .getOnlyChild() // EXPR_RESULT
@@ -3957,7 +3953,6 @@ public void testBigIntLiteralBinary() {
 
   @Test
   public void testBigIntLiteralOctal() {
-    mode = LanguageMode.UNSUPPORTED;
     Node bigint =
         parse("0o100n;") // SCRIPT
             .getOnlyChild() // EXPR_RESULT
@@ -3971,7 +3966,6 @@ public void testBigIntLiteralOctal() {
 
   @Test
   public void testBigIntLiteralHex() {
-    mode = LanguageMode.UNSUPPORTED;
     Node bigint =
         parse("0xFn;") // SCRIPT
             .getOnlyChild() // EXPR_RESULT
@@ -3985,7 +3979,6 @@ public void testBigIntLiteralHex() {
 
   @Test
   public void testBigIntLiteralErrors() {
-    mode = LanguageMode.UNSUPPORTED;
     parseError("01n;", "SyntaxError: nonzero BigInt can't have leading zero");
     parseError(".1n", "Semi-colon expected");
     parseError("0.1n", "Semi-colon expected");
@@ -3994,12 +3987,14 @@ public void testBigIntLiteralErrors() {
 
   @Test
   public void testBigIntLiteralWarning() {
-    parseWarning("1n;", "This language feature is not currently supported by the compiler: bigint");
+    mode = LanguageMode.ECMASCRIPT_2019;
+    parseWarning(
+        "1n;",
+        "This language feature is only supported for ECMASCRIPT_2020 mode or better: bigint");
   }
 
   @Test
   public void testBigIntLiteralInCall() {
-    mode = LanguageMode.UNSUPPORTED;
     parse("alert(1n)");
   }