Handle ternary intersection types

dev/core/src/com/google/gwt/dev/javac/JdtUtil.java

@@ -366,7 +366,7 @@ public static String signature(MethodBinding binding) {
   }
 
   public static String signature(TypeBinding binding) {
-    assert !binding.isIntersectionType18() && !binding.isIntersectionType();
+    assert !binding.isIntersectionType18() && !binding.isIntersectionType() : binding.debugName();
     if (binding.isBaseType()) {
       return String.valueOf(binding.sourceName());
     } else {

dev/core/src/com/google/gwt/dev/jjs/impl/GwtAstBuilder.java

@@ -638,7 +638,14 @@ public void endVisit(CompoundAssignment x, BlockScope scope) {
     public void endVisit(ConditionalExpression x, BlockScope scope) {
       try {
         SourceInfo info = makeSourceInfo(x);
-        JType type = typeMap.get(x.resolvedType);
+        JType type;
+        if (x.resolvedType instanceof IntersectionTypeBinding18) {
+          type = typeMap.get(
+                  getFirstNonObjectInIntersection((IntersectionTypeBinding18) x.resolvedType)
+          );
+        } else {
+          type = typeMap.get(x.resolvedType);
+        }
         JExpression valueIfFalse = pop(x.valueIfFalse);
         JExpression valueIfTrue = pop(x.valueIfTrue);
         JExpression condition = pop(x.condition);
@@ -648,6 +655,27 @@ public void endVisit(ConditionalExpression x, BlockScope scope) {
       }
     }
 
+    /**
+     * Returns the first non-Object type in the intersection. As intersections can only contain one
+     * class, and that class must be first, this ensures that if there is a class it will be the
+     * returned type, but if there are only interfaces, the first interface will be selected.
+     * <p></p>
+     * This behavior is consistent with ReferenceMapper.get() with assertions disabled - that is,
+     * where {@code referenceMapper.get(foo)} would fail due to an assertion, if assertions are
+     * disabled then {@code
+     * referenceMapper.get(foo).equals(referenceMapper.get(getFirstNonObjectInIntersection(foo))
+     * } will be true.
+     */
+    private TypeBinding getFirstNonObjectInIntersection(IntersectionTypeBinding18 resolvedType) {
+      for (ReferenceBinding type : resolvedType.intersectingTypes) {
+        if (type != curCud.cud.scope.getJavaLangObject()) {
+          return type;
+        }
+      }
+      throw new IllegalStateException("Type doesn't have a non-java.lang.Object it intersects "
+              + resolvedType);
+    }
+
     @Override
     public void endVisit(ConstructorDeclaration x, ClassScope scope) {
       try {
@@ -2941,7 +2969,13 @@ private JLocal createLocal(LocalDeclaration x) {
       TypeBinding resolvedType = x.type.resolvedType;
       JType localType;
       if (resolvedType.constantPoolName() != null) {
-        localType = typeMap.get(resolvedType);
+        if (resolvedType instanceof IntersectionTypeBinding18) {
+          localType = typeMap.get(
+                  getFirstNonObjectInIntersection((IntersectionTypeBinding18) resolvedType)
+          );
+        } else {
+          localType = typeMap.get(resolvedType);
+        }
       } else {
         // Special case, a statically unreachable local type.
         localType = JReferenceType.NULL_TYPE;

user/src/com/google/gwt/junit/JUnitShell.java

@@ -17,7 +17,6 @@
 
 import com.google.gwt.core.ext.Linker;
 import com.google.gwt.core.ext.TreeLogger;
-import com.google.gwt.core.ext.TreeLogger.Type;
 import com.google.gwt.core.ext.UnableToCompleteException;
 import com.google.gwt.core.ext.linker.impl.StandardLinkerContext;
 import com.google.gwt.core.ext.typeinfo.JClassType;
@@ -1092,7 +1091,8 @@ void compileForWebMode(ModuleDef module, Set<String> userAgents)
     try {
       success = Compiler.compile(getTopLogger(), options, module);
     } catch (Exception e) {
-      getTopLogger().log(Type.ERROR, "Compiler aborted with an exception ", e);
+      // noinspection ThrowableNotThrown
+      CompilationProblemReporter.logAndTranslateException(getTopLogger(), e);
     }
     if (!success) {
       throw new UnableToCompleteException();

user/test-super/com/google/gwt/dev/jjs/super/com/google/gwt/dev/jjs/test/Java10Test.java

@@ -21,8 +21,10 @@
 import java.util.ArrayList;
 import java.util.function.Supplier;
 
+import java.io.Serializable;
+
 /**
- * Tests Java 10 features. It is super sourced so that gwt can be compiles under Java 7.
+ * Tests Java 10 features. It is super sourced so that gwt can be compiled under Java 7.
  *
  * IMPORTANT: For each test here there must exist the corresponding method in the non super sourced
  * version.
@@ -65,6 +67,29 @@ public void testLocalVarType_Anonymous() {
     assertEquals("42", o.s);
   }
 
+  public void testLocalVarType_Ternary() {
+    var value = true ? "a" : 'c';
+    checkSerializableDispatch(value);
+    checkComparableDispatch(value);
+    assertEquals("a", value.toString());
+  }
+
+  private void checkSerializableDispatch(Object fail) {
+    fail("should not be treated as object");
+  }
+
+  private void checkSerializableDispatch(Serializable pass) {
+    // pass
+  }
+
+  private void checkComparableDispatch(Object fail) {
+    fail("should not be treated as object");
+  }
+
+  private void checkComparableDispatch(Comparable<?> pass) {
+    // pass
+  }
+
   public void testLocalVarType_LambdaCapture() {
     var s = "42";
     Supplier<String> supplier = () -> s;

user/test/com/google/gwt/dev/jjs/test/CompilerTest.java

@@ -583,6 +583,9 @@ public void testConditionals() {
     assertFalse(FALSE ? TRUE : false);
     assertFalse(TRUE ? FALSE : true);
     assertTrue(FALSE ? FALSE : true);
+
+    assertEquals("abc", "ab" + (TRUE ? "c" : 'z'));
+    assertEquals("abz", "ab" + (FALSE ? "c" : 'z'));
   }
 
   /**

user/test/com/google/gwt/dev/jjs/test/Java10Test.java

@@ -50,6 +50,10 @@ public void testLocalVarType_Anonymous() {
     assertFalse(isGwtSourceLevel10());
   }
 
+  public void testLocalVarType_Ternary() {
+    assertFalse(isGwtSourceLevel10());
+  }
+
   public void testLocalVarType_LambdaCapture() {
     assertFalse(isGwtSourceLevel10());
   }