[JS] Emit switch expressions using EmbeddedStatement.

PiperOrigin-RevId: 718534144

transpiler/java/com/google/j2cl/transpiler/ast/EmbeddedStatement.java

@@ -49,7 +49,9 @@ public TypeDescriptor getTypeDescriptor() {
 
   @Override
   public Precedence getPrecedence() {
-    return Precedence.HIGHEST;
+    // EmbeddedStatement is emitted as an IIFE in JavaScript, hence the precedence is the same
+    // as the one for method call.
+    return Precedence.MEMBER_ACCESS;
   }
 
   @Override

transpiler/java/com/google/j2cl/transpiler/ast/TypeDescriptors.java

@@ -98,20 +98,6 @@ public class TypeDescriptors {
   @QualifiedBinaryName("java.util.ReadonlyMap")
   public DeclaredTypeDescriptor javaUtilReadonlyMap;
 
-  public DeclaredTypeDescriptor javaUtilFunctionSupplier;
-
-  @QualifiedBinaryName("java.util.function.BooleanSupplier")
-  public DeclaredTypeDescriptor javaUtilFunctionBooleanSupplier;
-
-  @QualifiedBinaryName("java.util.function.IntSupplier")
-  public DeclaredTypeDescriptor javaUtilFunctionIntSupplier;
-
-  @QualifiedBinaryName("java.util.function.LongSupplier")
-  public DeclaredTypeDescriptor javaUtilFunctionLongSupplier;
-
-  @QualifiedBinaryName("java.util.function.DoubleSupplier")
-  public DeclaredTypeDescriptor javaUtilFunctionDoubleSupplier;
-
   public DeclaredTypeDescriptor javaIoSerializable;
 
   @Nullable

transpiler/java/com/google/j2cl/transpiler/backend/closure/ExpressionTranspiler.java

@@ -28,9 +28,11 @@
 import com.google.j2cl.transpiler.ast.AstUtils;
 import com.google.j2cl.transpiler.ast.AwaitExpression;
 import com.google.j2cl.transpiler.ast.BinaryExpression;
+import com.google.j2cl.transpiler.ast.Block;
 import com.google.j2cl.transpiler.ast.CastExpression;
 import com.google.j2cl.transpiler.ast.ConditionalExpression;
 import com.google.j2cl.transpiler.ast.DeclaredTypeDescriptor;
+import com.google.j2cl.transpiler.ast.EmbeddedStatement;
 import com.google.j2cl.transpiler.ast.Expression;
 import com.google.j2cl.transpiler.ast.Expression.Precedence;
 import com.google.j2cl.transpiler.ast.ExpressionWithComment;
@@ -52,6 +54,7 @@
 import com.google.j2cl.transpiler.ast.PostfixExpression;
 import com.google.j2cl.transpiler.ast.PrefixExpression;
 import com.google.j2cl.transpiler.ast.PrefixOperator;
+import com.google.j2cl.transpiler.ast.Statement;
 import com.google.j2cl.transpiler.ast.SuperReference;
 import com.google.j2cl.transpiler.ast.ThisReference;
 import com.google.j2cl.transpiler.ast.TypeDescriptor;
@@ -149,6 +152,24 @@ public boolean enterExpressionWithComment(ExpressionWithComment expressionWithCo
         return false;
       }
 
+      @Override
+      public boolean enterEmbeddedStatement(EmbeddedStatement expression) {
+        // Emit the embedded statements as a parameterless IIFE.
+        sourceBuilder.append("(() =>");
+        Statement statement = expression.getStatement();
+        StatementTranspiler.render(
+            statement instanceof Block
+                ? statement
+                : Block.newBuilder()
+                    .setStatements(statement)
+                    .setSourcePosition(statement.getSourcePosition())
+                    .build(),
+            environment,
+            sourceBuilder);
+        sourceBuilder.append(")()");
+        return false;
+      }
+
       @Override
       public boolean enterFieldAccess(FieldAccess fieldAccess) {
         String fieldMangledName = fieldAccess.getTarget().getMangledName();

transpiler/java/com/google/j2cl/transpiler/backend/wasm/ExpressionTranspiler.java

@@ -329,6 +329,8 @@ public boolean enterMultiExpression(MultiExpression multiExpression) {
       public boolean enterEmbeddedStatement(EmbeddedStatement embeddedStatement) {
         Statement statement = embeddedStatement.getStatement();
         Label label = null;
+        // TODO(b/391582571): Use a cleaner representation for a labeled block that has a
+        // return value.
         if (statement instanceof LabeledStatement) {
           LabeledStatement labeledStatement = (LabeledStatement) statement;
           label = labeledStatement.getLabel();

transpiler/java/com/google/j2cl/transpiler/passes/ImplementSwitchExpressionsViaIifes.java

@@ -17,21 +17,15 @@
 
 import com.google.j2cl.transpiler.ast.AbstractRewriter;
 import com.google.j2cl.transpiler.ast.CompilationUnit;
-import com.google.j2cl.transpiler.ast.DeclaredTypeDescriptor;
-import com.google.j2cl.transpiler.ast.FunctionExpression;
-import com.google.j2cl.transpiler.ast.LambdaAdaptorTypeDescriptors;
-import com.google.j2cl.transpiler.ast.MethodCall;
+import com.google.j2cl.transpiler.ast.EmbeddedStatement;
 import com.google.j2cl.transpiler.ast.Node;
 import com.google.j2cl.transpiler.ast.ReturnStatement;
 import com.google.j2cl.transpiler.ast.SwitchExpression;
 import com.google.j2cl.transpiler.ast.SwitchStatement;
-import com.google.j2cl.transpiler.ast.TypeDescriptor;
-import com.google.j2cl.transpiler.ast.TypeDescriptors;
 import com.google.j2cl.transpiler.ast.YieldStatement;
 
 /**
- * Implements switch expressions as an immediately invoked function expressions that executes a
- * switch statement..
+ * Implements switch expressions using EmbeddedStatements which are emitted as IIFEs.
  *
  * <p>In JavaScript switch constructs are only allowed as statements. This pass converts the switch
  * expression into switch statement and wraps it into an IIFE which allows us to execute a statement
@@ -72,16 +66,10 @@ public void applyTo(CompilationUnit compilationUnit) {
 
           @Override
           public Node rewriteSwitchExpression(SwitchExpression switchExpression) {
-            DeclaredTypeDescriptor supplierJsFunctionTypeDescriptor =
-                getSupplierJsFunction(switchExpression.getTypeDescriptor());
-
-            return MethodCall.Builder.from(
-                    supplierJsFunctionTypeDescriptor.getJsFunctionMethodDescriptor())
-                .setQualifier(
-                    // Enclose the switch expression as a switch statement inside a function.
-                    FunctionExpression.newBuilder()
-                        .setTypeDescriptor(supplierJsFunctionTypeDescriptor)
-                        .setStatements(SwitchStatement.Builder.from(switchExpression).build())
+            return EmbeddedStatement.newBuilder()
+                .setTypeDescriptor(switchExpression.getTypeDescriptor())
+                .setStatement(
+                    SwitchStatement.Builder.from(switchExpression)
                         .setSourcePosition(switchExpression.getSourcePosition())
                         .build())
                 .build();
@@ -96,27 +84,4 @@ public ReturnStatement rewriteYieldStatement(YieldStatement yieldStatement) {
           }
         });
   }
-
-  /** Returns the JsFunction supplier with the appropriate type for {@code typeDescriptor}. */
-  private DeclaredTypeDescriptor getSupplierJsFunction(TypeDescriptor typeDescriptor) {
-    // TODO(b/112308901): remove this hacky code when function types are modeled better.
-    return LambdaAdaptorTypeDescriptors.createJsFunctionTypeDescriptor(
-        getSupplierType(typeDescriptor));
-  }
-
-  /** Returns the supplier that is most suitable to be used for {@code typeDescriptor}. */
-  private DeclaredTypeDescriptor getSupplierType(TypeDescriptor typeDescriptor) {
-    if (!typeDescriptor.isPrimitive()) {
-      return TypeDescriptors.get()
-          .javaUtilFunctionSupplier
-          .specializeTypeVariables(typeVariable -> typeDescriptor);
-    } else if (TypeDescriptors.isPrimitiveBoolean(typeDescriptor)) {
-      return TypeDescriptors.get().javaUtilFunctionBooleanSupplier;
-    } else if (TypeDescriptors.isPrimitiveFloatOrDouble(typeDescriptor)) {
-      return TypeDescriptors.get().javaUtilFunctionDoubleSupplier;
-    } else if (TypeDescriptors.isPrimitiveLong(typeDescriptor)) {
-      return TypeDescriptors.get().javaUtilFunctionLongSupplier;
-    }
-    return TypeDescriptors.get().javaUtilFunctionIntSupplier;
-  }
 }

transpiler/javatests/com/google/j2cl/readable/java/sourcemap/output_closure/SourceMap.js.mappings.txt

@@ -132,9 +132,9 @@
         }] => [switch (v) {
     case 1: case 2:
 ...     return 20;
-   }] "sourcemap.SourceMap.<lambda in testSwitchExpression>"
-[10;] => [return 10;] "sourcemap.SourceMap.<lambda in testSwitchExpression>"
-[20;] => [return 20;] "sourcemap.SourceMap.<lambda in testSwitchExpression>"
+   }] "sourcemap.SourceMap.testSwitchExpression"
+[10;] => [return 10;] "sourcemap.SourceMap.testSwitchExpression"
+[20;] => [return 20;] "sourcemap.SourceMap.testSwitchExpression"
 [SourceMap] => [m_reversed__java_util_Comparator]
 [SourceMap] => [return /**@type {Comparator<T>}*/ (Comparator.m_reversed__$default__java_util_Comparator__java_util_Comparator(this));] "sourcemap.SourceMap.reversed"
 [SourceMap] => [m_thenComparing__java_util_Comparator__java_util_Comparator]