Change the programmatic interface to compiler options to no longer ha…

…ve a language out but an output feature set. This allows anything linking against the compiler to be much more specific in what it wants out (e.g. "Please give me ES2017 but without modules").

Note that for the CLI there is still only a language out option. But the language out represents a feature set.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=198058737

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

@@ -114,7 +114,7 @@ boolean nodeTypeMayHaveSideEffects(Node n) {
    */
   boolean isEcmaScript5OrGreater() {
     return compiler != null
-        && compiler.getOptions().getLanguageOut().toFeatureSet().contains(FeatureSet.ES5);
+        && compiler.getOptions().getOutputFeatureSet().contains(FeatureSet.ES5);
   }
 
   /**

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

@@ -32,6 +32,7 @@
 import com.google.javascript.jscomp.graph.GraphNode;
 import com.google.javascript.jscomp.graph.LinkedUndirectedGraph;
 import com.google.javascript.jscomp.graph.UndiGraph;
+import com.google.javascript.jscomp.parsing.parser.FeatureSet;
 import com.google.javascript.rhino.IR;
 import com.google.javascript.rhino.Node;
 import com.google.javascript.rhino.Token;
@@ -137,7 +138,7 @@ public void enterScope(NodeTraversal t) {
         new LiveVariablesAnalysis(
             cfg, scope, null, compiler, new Es6SyntacticScopeCreator(compiler));
 
-    if (compiler.getOptions().getLanguageOut() == CompilerOptions.LanguageMode.ECMASCRIPT3) {
+    if (FeatureSet.ES3.contains(compiler.getOptions().getOutputFeatureSet())) {
       // If the function has exactly 2 params, mark them as escaped. This is a work-around for a
       // bug in IE 8 and below, where it throws an exception if you write to the parameters of the
       // callback in a sort(). See http://blickly.github.io/closure-compiler-issues/#58 and

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

@@ -23,7 +23,7 @@
 import com.google.common.collect.ImmutableList;
 import com.google.debugging.sourcemap.FilePosition;
 import com.google.javascript.jscomp.CodePrinter.Builder.CodeGeneratorFactory;
-import com.google.javascript.jscomp.CompilerOptions.LanguageMode;
+import com.google.javascript.jscomp.parsing.parser.FeatureSet;
 import com.google.javascript.rhino.Node;
 import com.google.javascript.rhino.StaticSourceFile;
 import com.google.javascript.rhino.Token;
@@ -837,7 +837,7 @@ static Format fromOptions(CompilerOptions options, boolean outputTypes, boolean
       if (outputTypes) {
         return Format.TYPED;
       }
-      if (prettyPrint || options.getLanguageOut() == LanguageMode.ECMASCRIPT6_TYPED) {
+      if (prettyPrint || options.getOutputFeatureSet().contains(FeatureSet.TYPESCRIPT)) {
         return Format.PRETTY;
       }
       return Format.COMPACT;

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

@@ -113,9 +113,11 @@ public enum PropertyCollapseLevel {
   private LanguageMode languageIn;
 
   /**
-   * The JavaScript language version that should be produced.
+   * The JavaScript features that are allowed to be in the output.
    */
-  private LanguageMode languageOut;
+  private FeatureSet outputFeatureSet;
+
+  private boolean languageOutIsDefaultStrict;
 
   /**
    * The builtin set of externs to be used
@@ -1216,7 +1218,8 @@ public void setPrintConfig(boolean printConfig) {
   public CompilerOptions() {
     // Accepted language
     languageIn = LanguageMode.ECMASCRIPT_2017;
-    languageOut = LanguageMode.NO_TRANSPILE;
+    outputFeatureSet = LanguageMode.NO_TRANSPILE.toFeatureSet();
+    languageOutIsDefaultStrict = false;
 
     // Which environment to use
     environment = Environment.BROWSER;
@@ -1913,7 +1916,7 @@ public TweakProcessing getTweakProcessing() {
   public void setLanguage(LanguageMode language) {
     checkState(language != LanguageMode.NO_TRANSPILE);
     this.languageIn = language;
-    this.languageOut = language;
+    this.setLanguageOut(language);
   }
 
   /**
@@ -1930,28 +1933,43 @@ public LanguageMode getLanguageIn() {
   }
 
   /**
-   * Sets ECMAScript version to use for the output. If you are not
-   * transpiling from one version to another, use #setLanguage instead.
+   * Sets ECMAScript version to use for the output.
+   *
+   * <p>If you are not transpiling from one version to another, use #setLanguage instead.
+   *
+   * <p>If you you need something more fine grained (e.g. "ES2017 without modules") use
+   * #setOutputFeatureSet.
    */
   public void setLanguageOut(LanguageMode languageOut) {
-    this.languageOut = languageOut;
+    this.languageOutIsDefaultStrict = languageOut.isDefaultStrict();
+    this.outputFeatureSet = languageOut.toFeatureSet();
   }
 
-  public LanguageMode getLanguageOut() {
-    if (languageOut == LanguageMode.NO_TRANSPILE) {
-      return languageIn;
-    }
-    return languageOut;
+  /**
+   * Sets the features that allowed to appear in the output. Any feature in the input that is not
+   * in this output must be transpiled away.
+   */
+  public void setOutputFeatureSet(FeatureSet featureSet) {
+    this.outputFeatureSet = featureSet;
+  }
+
+  /**
+   * Gets the set of features that can appear in the output.
+   */
+  public FeatureSet getOutputFeatureSet() {
+    return outputFeatureSet;
   }
 
   public boolean needsTranspilationFrom(FeatureSet languageLevel) {
+    // TODO(johnplaisted): This isn't really accurate. This should instead be the *parsed* language,
+    // not the *input* language.
     return getLanguageIn().toFeatureSet().contains(languageLevel)
-        && !getLanguageOut().toFeatureSet().contains(languageLevel);
+        && !getOutputFeatureSet().contains(languageLevel);
   }
 
   public boolean needsTranspilationOf(FeatureSet.Feature feature) {
     return getLanguageIn().toFeatureSet().has(feature)
-        && !getLanguageOut().toFeatureSet().has(feature);
+        && !getOutputFeatureSet().has(feature);
   }
 
   /**
@@ -2632,7 +2650,7 @@ public boolean shouldQuoteKeywordProperties() {
     if (incrementalCheckMode == IncrementalCheckMode.GENERATE_IJS) {
       return false;
     }
-    return this.quoteKeywordProperties || languageOut == LanguageMode.ECMASCRIPT3;
+    return this.quoteKeywordProperties || FeatureSet.ES3.contains(getOutputFeatureSet());
   }
 
   public void setErrorFormat(ErrorFormat errorFormat) {
@@ -2802,8 +2820,11 @@ public void setConformanceConfigs(List<ConformanceConfig> configs) {
             .build();
   }
 
+  /**
+   * Whether the output should contain a 'use strict' directive.
+   */
   public boolean shouldEmitUseStrict() {
-    return this.emitUseStrict.or(getLanguageOut().isDefaultStrict());
+    return this.emitUseStrict.or(languageOutIsDefaultStrict);
   }
 
   public CompilerOptions setEmitUseStrict(boolean emitUseStrict) {
@@ -2956,7 +2977,7 @@ public String toString() {
             .add("j2clPassMode", j2clPassMode)
             .add("labelRenaming", labelRenaming)
             .add("languageIn", getLanguageIn())
-            .add("languageOut", getLanguageOut())
+            .add("languageOutIsDefaultStrict", languageOutIsDefaultStrict)
             .add("legacyCodeCompile", legacyCodeCompile)
             .add("lineBreak", lineBreak)
             .add("lineLengthThreshold", lineLengthThreshold)
@@ -2972,6 +2993,7 @@ public String toString() {
             .add("optimizeArgumentsArray", optimizeArgumentsArray)
             .add("optimizeCalls", optimizeCalls)
             .add("outputCharset", outputCharset)
+            .add("outputFeatureSet", outputFeatureSet)
             .add("outputJs", outputJs)
             .add("outputJsStringUsage", outputJsStringUsage)
             .add(
@@ -3066,7 +3088,7 @@ public String toString() {
    * the same compilation job. Therefore, the 'use strict' directive is ignored
    * when the language mode is not strict.
    */
-  public static enum LanguageMode {
+  public enum LanguageMode {
     /**
      * 90's JavaScript
      */
@@ -3157,11 +3179,10 @@ public FeatureSet toFeatureSet() {
         case ECMASCRIPT_2018:
           return FeatureSet.ES2018_MODULES;
         case ECMASCRIPT_NEXT:
+        case NO_TRANSPILE:
           return FeatureSet.ES_NEXT;
         case ECMASCRIPT6_TYPED:
           return FeatureSet.TYPESCRIPT;
-        case NO_TRANSPILE:
-          throw new IllegalStateException();
       }
       throw new IllegalStateException();
     }

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

@@ -56,7 +56,7 @@ static void preprocess(CompilerOptions options) {
     }
 
     if (options.dartPass) {
-      if (!options.getLanguageOut().toFeatureSet().contains(FeatureSet.ES5)) {
+      if (!options.getOutputFeatureSet().contains(FeatureSet.ES5)) {
         throw new InvalidOptionsException("Dart requires --language_out=ES5 or higher.");
       }
       // --dart_pass does not support type-aware property renaming yet.

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

@@ -54,7 +54,7 @@ public DartSuperAccessorsPass(AbstractCompiler compiler) {
     this.renameProperties = options.propertyRenaming == PropertyRenamingPolicy.ALL_UNQUOTED;
 
     checkState(
-        options.getLanguageOut().toFeatureSet().contains(FeatureSet.ES5),
+        options.getOutputFeatureSet().contains(FeatureSet.ES5),
         "Dart super accessors pass requires ES5+ output");
 
     // We currently rely on JSCompiler_renameProperty, which is not type-aware.

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

@@ -371,7 +371,7 @@ protected List<PassFactory> getChecks() {
 
     // It's important that the Dart super accessors pass run *before* es6ConvertSuper,
     // which is a "late" ES6 pass. This is enforced in the assertValidOrder method.
-    if (options.dartPass && !options.getLanguageOut().toFeatureSet().contains(ES6)) {
+    if (options.dartPass && !options.getOutputFeatureSet().contains(ES6)) {
       checks.add(dartSuperAccessorsPass);
     }
 
@@ -894,7 +894,7 @@ protected List<PassFactory> getOptimizations() {
     passes.add(varCheckValidity);
 
     // Raise to ES6, if allowed
-    if (options.getLanguageOut().toFeatureSet().contains(ES6)) {
+    if (options.getOutputFeatureSet().contains(ES6)) {
       passes.add(optimizeToEs6);
     }
 
@@ -2374,7 +2374,7 @@ protected CompilerPass create(final AbstractCompiler compiler) {
           return new ClosureOptimizePrimitives(
               compiler,
               compiler.getOptions().propertyRenaming == PropertyRenamingPolicy.ALL_UNQUOTED,
-              compiler.getOptions().getLanguageOut().toFeatureSet().contains(ES6));
+              compiler.getOptions().getOutputFeatureSet().contains(ES6));
         }
 
         @Override

src/com/google/javascript/jscomp/Es6InjectRuntimeLibraries.java

@@ -15,7 +15,6 @@
  */
 package com.google.javascript.jscomp;
 
-import com.google.javascript.jscomp.CompilerOptions.LanguageMode;
 import com.google.javascript.jscomp.NodeTraversal.Callback;
 import com.google.javascript.jscomp.parsing.parser.FeatureSet;
 import com.google.javascript.rhino.IR;
@@ -65,7 +64,7 @@ public boolean shouldTraverse(NodeTraversal t, Node n, Node parent) {
         break;
       case GETTER_DEF:
       case SETTER_DEF:
-        if (compiler.getOptions().getLanguageOut() == LanguageMode.ECMASCRIPT3) {
+        if (FeatureSet.ES3.contains(compiler.getOptions().getOutputFeatureSet())) {
           Es6ToEs3Util.cannotConvert(
               compiler, n, "ES5 getters/setters (consider using --language_out=ES5)");
         }

src/com/google/javascript/jscomp/Es6RewriteClass.java

@@ -22,7 +22,6 @@
 
 import com.google.common.base.Preconditions;
 import com.google.common.collect.Iterables;
-import com.google.javascript.jscomp.CompilerOptions.LanguageMode;
 import com.google.javascript.jscomp.parsing.parser.FeatureSet;
 import com.google.javascript.jscomp.parsing.parser.FeatureSet.Feature;
 import com.google.javascript.rhino.IR;
@@ -100,7 +99,7 @@ public boolean shouldTraverse(NodeTraversal t, Node n, Node parent) {
     switch (n.getToken()) {
       case GETTER_DEF:
       case SETTER_DEF:
-        if (compiler.getOptions().getLanguageOut() == LanguageMode.ECMASCRIPT3) {
+        if (FeatureSet.ES3.contains(compiler.getOptions().getOutputFeatureSet())) {
           cannotConvert(n, "ES5 getters/setters (consider using --language_out=ES5)");
           return false;
         }

src/com/google/javascript/jscomp/Es6RewriteRestAndSpread.java

@@ -18,7 +18,6 @@
 import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.base.Preconditions.checkState;
 
-import com.google.javascript.jscomp.CompilerOptions.LanguageMode;
 import com.google.javascript.jscomp.NodeUtil.Visitor;
 import com.google.javascript.jscomp.parsing.parser.FeatureSet;
 import com.google.javascript.jscomp.parsing.parser.FeatureSet.Feature;
@@ -499,7 +498,7 @@ private void visitNewWithSpread(Node spreadParent) {
                     groups.toArray(new Node[0]))
                 .setJSType(arrayType);
 
-    if (compiler.getOptions().getLanguageOut() == LanguageMode.ECMASCRIPT3) {
+    if (FeatureSet.ES3.contains(compiler.getOptions().getOutputFeatureSet())) {
       // TODO(tbreisacher): Support this in ES3 too by not relying on Function.bind.
       Es6ToEs3Util.cannotConvert(
           compiler,

src/com/google/javascript/jscomp/LateEs6ToEs3Converter.java

@@ -20,7 +20,6 @@
 import static com.google.javascript.jscomp.Es6ToEs3Util.withType;
 
 import com.google.common.collect.Lists;
-import com.google.javascript.jscomp.CompilerOptions.LanguageMode;
 import com.google.javascript.jscomp.parsing.parser.FeatureSet;
 import com.google.javascript.jscomp.parsing.parser.FeatureSet.Feature;
 import com.google.javascript.rhino.IR;
@@ -88,7 +87,7 @@ public boolean shouldTraverse(NodeTraversal t, Node n, Node parent) {
     switch (n.getToken()) {
       case GETTER_DEF:
       case SETTER_DEF:
-        if (compiler.getOptions().getLanguageOut() == LanguageMode.ECMASCRIPT3) {
+        if (FeatureSet.ES3.contains(compiler.getOptions().getOutputFeatureSet())) {
           Es6ToEs3Util.cannotConvert(
               compiler, n, "ES5 getters/setters (consider using --language_out=ES5)");
           return false;

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

@@ -247,7 +247,7 @@ public void visitGuarded(NodeTraversal traversal, Node node, Node parent) {
                 node,
                 INSUFFICIENT_OUTPUT_VERSION_ERROR,
                 name,
-                compiler.getOptions().getLanguageOut().toString());
+                compiler.getOptions().getOutputFeatureSet().version());
           }
           inject(polyfill);
 
@@ -292,7 +292,7 @@ private void inject(Polyfill polyfill) {
       ImmutableSet.of("goog.global.", "window.");
 
   private boolean languageOutIsAtLeast(LanguageMode mode) {
-    return compiler.getOptions().getLanguageOut().compareTo(mode) >= 0;
+    return compiler.getOptions().getOutputFeatureSet().contains(mode.toFeatureSet());
   }
 
   private boolean languageOutIsAtLeast(FeatureSet features) {

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

@@ -122,7 +122,7 @@ protected CompilerPass create(AbstractCompiler compiler) {
 
         @Override
         protected FeatureSet featureSet() {
-          return ES8_MODULES;
+          return FeatureSet.latest();
         }
       };
 
@@ -422,7 +422,7 @@ static boolean doesScriptHaveUnsupportedFeatures(Node script, FeatureSet support
   static void processTranspile(
       AbstractCompiler compiler, Node combinedRoot, FeatureSet featureSet, Callback... callbacks) {
     if (compiler.getOptions().needsTranspilationFrom(featureSet)) {
-      FeatureSet languageOutFeatures = compiler.getOptions().getLanguageOut().toFeatureSet();
+      FeatureSet languageOutFeatures = compiler.getOptions().getOutputFeatureSet();
       for (Node singleRoot : combinedRoot.children()) {
 
         // Only run the transpilation if this file has features not in the compiler's target output
@@ -454,7 +454,7 @@ static void processTranspile(
   static void hotSwapTranspile(
       AbstractCompiler compiler, Node scriptRoot, FeatureSet featureSet, Callback... callbacks) {
     if (compiler.getOptions().needsTranspilationFrom(featureSet)) {
-      FeatureSet languageOutFeatures = compiler.getOptions().getLanguageOut().toFeatureSet();
+      FeatureSet languageOutFeatures = compiler.getOptions().getOutputFeatureSet();
       if (doesScriptHaveUnsupportedFeatures(scriptRoot, languageOutFeatures)) {
         for (Callback callback : callbacks) {
           scriptRoot.putBooleanProp(Node.TRANSPILED, true);