Don't break lambda bodies during tree pruning

Rewriting block-bodied lambda bodies into empty blocks breaks
breaks overload resolution.

--
MOS_MIGRATED_REVID=138936301

2 files changed, 70 insertions, 23 deletions

diff --git a/src/java_tools/buildjar/javatests/com/google/devtools/build/java/turbine/javac/JavacTurbineTest.java b/src/java_tools/buildjar/javatests/com/google/devtools/build/java/turbine/javac/JavacTurbineTest.java
index 39fe109e7c..acc9d595f3 100644
--- a/src/java_tools/buildjar/javatests/com/google/devtools/build/java/turbine/javac/JavacTurbineTest.java
+++ b/src/java_tools/buildjar/javatests/com/google/devtools/build/java/turbine/javac/JavacTurbineTest.java
@@ -1341,4 +1341,46 @@ public class JavacTurbineTest {
     };
     assertThat(text).isEqualTo(Joiner.on('\n').join(expected));
   }
+
+  @Test
+  public void lambdaBody() throws Exception {
+    addSourceLines(
+        "P.java",
+        "import java.util.function.Predicate;",
+        "enum P {",
+        "  INSTANCE(x -> {",
+        "    return false;",
+        "  });",
+        "  P(Predicate<String> p) {}",
+        "}");
+
+    compile();
+
+    Map<String, byte[]> outputs = collectOutputs();
+
+    String text = textify(outputs.get("P.class"));
+    String[] expected = {
+      "// class version 52.0 (52)",
+      "// access flags 0x4030",
+      "// signature Ljava/lang/Enum<LP;>;",
+      "// declaration: P extends java.lang.Enum<P>",
+      "final enum P extends java/lang/Enum  {",
+      "",
+      "  // access flags 0x19",
+      "  public final static INNERCLASS java/lang/invoke/MethodHandles$Lookup"
+          + " java/lang/invoke/MethodHandles Lookup",
+      "",
+      "  // access flags 0x4019",
+      "  public final static enum LP; INSTANCE",
+      "",
+      "  // access flags 0x9",
+      "  public static values()[LP;",
+      "",
+      "  // access flags 0x9",
+      "  public static valueOf(Ljava/lang/String;)LP;",
+      "}",
+      ""
+    };
+    assertThat(text).isEqualTo(Joiner.on('\n').join(expected));
+  }
 }
diff --git a/src/java_tools/buildjar/javatests/com/google/devtools/build/java/turbine/javac/TreePrunerTest.java b/src/java_tools/buildjar/javatests/com/google/devtools/build/java/turbine/javac/TreePrunerTest.java
index 5f3962b9ad..bebb093e14 100644
--- a/src/java_tools/buildjar/javatests/com/google/devtools/build/java/turbine/javac/TreePrunerTest.java
+++ b/src/java_tools/buildjar/javatests/com/google/devtools/build/java/turbine/javac/TreePrunerTest.java
@@ -19,7 +19,6 @@ import static com.google.common.truth.Truth.assertThat;
 import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.google.common.base.Joiner;
-
 import com.sun.tools.javac.file.JavacFileManager;
 import com.sun.tools.javac.parser.JavacParser;
 import com.sun.tools.javac.parser.ParserFactory;
@@ -27,7 +26,7 @@ import com.sun.tools.javac.tree.JCTree.JCClassDecl;
 import com.sun.tools.javac.tree.JCTree.JCCompilationUnit;
 import com.sun.tools.javac.tree.JCTree.JCVariableDecl;
 import com.sun.tools.javac.util.Context;
-
+import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
@@ -36,7 +35,16 @@ import org.junit.runners.JUnit4;
 @RunWith(JUnit4.class)
 public class TreePrunerTest {
 
-  static JCCompilationUnit parseLines(String... lines) {
+  Context context;
+
+  @Before
+  public void setUp() {
+    this.context = new Context();
+    // registers itself in the context as a side effect
+    new JavacFileManager(context, true, UTF_8);
+  }
+
+  JCCompilationUnit parseLines(String... lines) {
     Context context = new Context();
     try (JavacFileManager fm = new JavacFileManager(context, true, UTF_8)) {
       ParserFactory parserFactory = ParserFactory.instance(context);
@@ -48,33 +56,31 @@ public class TreePrunerTest {
     }
   }
 
-  static JCVariableDecl parseField(String line) {
+  JCVariableDecl parseField(String line) {
     JCCompilationUnit unit = parseLines("class T {", line, "}");
     JCClassDecl classDecl = (JCClassDecl) getOnlyElement(unit.defs);
     return (JCVariableDecl) getOnlyElement(classDecl.defs);
   }
 
-  static String printPruned(String line) {
+  String printPruned(String line) {
     JCVariableDecl tree = parseField(line);
-    TreePruner.prune(tree);
+    TreePruner.prune(context, tree);
     return tree.toString();
   }
 
   @Test
   public void hello() {
     String[] lines = {
-      "class Test {",
-      // TODO(cushon): fix google-java-format's handling of lists of string literals
+      "class Test {", //
       "  void f() {",
       "    System.err.println(\"hello\");",
       "  }",
       "}",
     };
     JCCompilationUnit tree = parseLines(lines);
-    TreePruner.prune(tree);
+    TreePruner.prune(context, tree);
     String[] expected = {
-      "class Test {",
-      // TODO(cushon): fix google-java-format's handling of lists of string literals
+      "class Test {", //
       "    ",
       "    void f() {",
       "    }",
@@ -96,13 +102,14 @@ public class TreePrunerTest {
       "}",
     };
     JCCompilationUnit tree = parseLines(lines);
-    TreePruner.prune(tree);
+    TreePruner.prune(context, tree);
     String[] expected = {
-      "class Test {",
-      // TODO(cushon): fix google-java-format's handling of lists of string literals
+      "class Test {", //
       "    {",
+      "        throw new AssertionError();",
       "    }",
       "    static {",
+      "        throw new AssertionError();",
       "    }",
       "}",
     };
@@ -112,8 +119,7 @@ public class TreePrunerTest {
   @Test
   public void nonConstantFieldInitializers() {
     String[] lines = {
-      "class Test {",
-      // TODO(cushon): fix google-java-format's handling of lists of string literals
+      "class Test {", //
       "  Object a = null;",
       "  int[] b = {1};",
       "  int c = g();",
@@ -121,10 +127,9 @@ public class TreePrunerTest {
       "}",
     };
     JCCompilationUnit tree = parseLines(lines);
-    TreePruner.prune(tree);
+    TreePruner.prune(context, tree);
     String[] expected = {
-      "class Test {",
-      // TODO(cushon): fix google-java-format's handling of lists of string literals
+      "class Test {", //
       "    Object a;",
       "    int[] b;",
       "    int c;",
@@ -238,7 +243,7 @@ public class TreePrunerTest {
       "}",
     };
     JCCompilationUnit tree = parseLines(lines);
-    TreePruner.prune(tree);
+    TreePruner.prune(context, tree);
     String[] expected = {
       "class Test {",
       "    ",
@@ -271,7 +276,7 @@ public class TreePrunerTest {
       "}",
     };
     JCCompilationUnit tree = parseLines(lines);
-    TreePruner.prune(tree);
+    TreePruner.prune(context, tree);
     String[] expected = {
       "@interface Anno {",
       "    ",
@@ -292,7 +297,7 @@ public class TreePrunerTest {
       "}",
     };
     JCCompilationUnit tree = parseLines(lines);
-    TreePruner.prune(tree);
+    TreePruner.prune(context, tree);
     String[] expected = {
       "interface Intf {",
       "    int CONST = 42;",
@@ -318,7 +323,7 @@ public class TreePrunerTest {
       "}",
     };
     JCCompilationUnit tree = parseLines(lines);
-    TreePruner.prune(tree);
+    TreePruner.prune(context, tree);
     String[] expected = {
         "class Test {",
         "    ",