[J2KT] Add debug logging to InsertQualifierProjectionCasts, and `De…

…scriber.getDescription()` methods for `TypeDeclaration` and `MethodDescriptor` which will be used in follow-up CLs.

PiperOrigin-RevId: 730595017

transpiler/java/com/google/j2cl/transpiler/passes/AbstractJ2ktNormalizationPass.java

@@ -18,11 +18,19 @@
 import static java.util.stream.Collectors.joining;
 
 import com.google.common.collect.ImmutableList;
+import com.google.errorprone.annotations.FormatMethod;
+import com.google.j2cl.common.SourcePosition;
+import com.google.j2cl.transpiler.ast.AbstractRewriter;
 import com.google.j2cl.transpiler.ast.ArrayTypeDescriptor;
 import com.google.j2cl.transpiler.ast.DeclaredTypeDescriptor;
+import com.google.j2cl.transpiler.ast.HasSourcePosition;
 import com.google.j2cl.transpiler.ast.IntersectionTypeDescriptor;
+import com.google.j2cl.transpiler.ast.MethodDescriptor;
+import com.google.j2cl.transpiler.ast.MethodDescriptor.ParameterDescriptor;
 import com.google.j2cl.transpiler.ast.NullabilityAnnotation;
 import com.google.j2cl.transpiler.ast.PrimitiveTypeDescriptor;
+import com.google.j2cl.transpiler.ast.Type;
+import com.google.j2cl.transpiler.ast.TypeDeclaration;
 import com.google.j2cl.transpiler.ast.TypeDescriptor;
 import com.google.j2cl.transpiler.ast.TypeVariable;
 import com.google.j2cl.transpiler.ast.UnionTypeDescriptor;
@@ -38,19 +46,68 @@
  * </ul>
  */
 public abstract class AbstractJ2ktNormalizationPass extends NormalizationPass {
+  private final Describer describer = new Describer();
+
+  // Prevent overriding and force using {@code applyTo(CompilationUnit)}.
+  @Override
+  public final void applyTo(Type type) {}
+
+  final Describer getDescriber() {
+    return describer;
+  }
+
+  @FormatMethod
+  final void debug(SourcePosition sourcePosition, String detailMessage, Object... args) {
+    getProblems().debug(sourcePosition, detailMessage, args);
+  }
+
+  @FormatMethod
+  final void debug(String detailMessage, Object... args) {
+    debug(SourcePosition.NONE, detailMessage, args);
+  }
+
+  /** Returns the closest meaningful source position from an enclosing node. */
+  final SourcePosition getSourcePosition(AbstractRewriter rewriter) {
+    HasSourcePosition hasSourcePosition =
+        (HasSourcePosition) rewriter.getParent(HasSourcePosition.class::isInstance);
+    return hasSourcePosition != null ? hasSourcePosition.getSourcePosition() : SourcePosition.NONE;
+  }
+
+  final String getDescription(TypeDescriptor typeDescriptor) {
+    return describer.getDescription(typeDescriptor, ImmutableList.of());
+  }
+
+  final String getDescription(TypeDeclaration typeDeclaration) {
+    return describer.getDescription(typeDeclaration);
+  }
+
+  final String getDescription(MethodDescriptor methodDescriptor) {
+    return describer.getDescription(methodDescriptor);
+  }
+
+  final String getTypeParameterDescription(TypeVariable typeVariable) {
+    return describer.getTypeParameterDescription(typeVariable);
+  }
 
   /**
    * Produces readable description string for AST nodes, containing information about resolved
    * nullability and captures with unique IDs. Used in Kotlin passes for debugging / development.
    */
   // TODO(b/382500942): Remove when no longer needed for debugging / development.
-  static final class Describer {
+  private static final class Describer {
     private final List<TypeVariable> seenCaptures = new ArrayList<>();
 
-    String getDescription(TypeDescriptor typeDescriptor) {
+    private Describer() {}
+
+    private String getDescription(TypeDescriptor typeDescriptor) {
       return getDescription(typeDescriptor, ImmutableList.of());
     }
 
+    private String getDescription(TypeDeclaration typeDeclaration) {
+      return typeDeclaration.getReadableDescription()
+          + getTypeParametersDescription(typeDeclaration.getTypeParameterDescriptors());
+    }
+
     @Nullable
     private static String getDescription(NullabilityAnnotation nullabilityAnnotation) {
       switch (nullabilityAnnotation) {
@@ -64,6 +121,28 @@ private static String getDescription(NullabilityAnnotation nullabilityAnnotation
       throw new AssertionError();
     }
 
+    private String getDescription(MethodDescriptor methodDescriptor) {
+      return String.format(
+          "%s%s (%s).%s%s%s",
+          appendSpaceIfNotEmpty(
+              getTypeParametersDescription(methodDescriptor.getTypeParameterTypeDescriptors())),
+          getDescription(methodDescriptor.getReturnTypeDescriptor()),
+          getDescription(methodDescriptor.getEnclosingTypeDescriptor()),
+          getTypeArgumentsDescription(methodDescriptor.getTypeArgumentTypeDescriptors()),
+          methodDescriptor.getName(),
+          getParametersDescription(methodDescriptor.getParameterDescriptors()));
+    }
+
+    private String getDescription(ParameterDescriptor parameterDescriptor) {
+      TypeDescriptor typeDescriptor = parameterDescriptor.getTypeDescriptor();
+      if (parameterDescriptor.isVarargs()) {
+        ArrayTypeDescriptor arrayTypeDescriptor = (ArrayTypeDescriptor) typeDescriptor;
+        return getDescription(arrayTypeDescriptor.getComponentTypeDescriptor()) + "...";
+      } else {
+        return getDescription(parameterDescriptor.getTypeDescriptor());
+      }
+    }
+
     private String getDescription(
         TypeDescriptor typeDescriptor, ImmutableList<TypeVariable> enclosingWildcardOrCaptures) {
       if (typeDescriptor instanceof PrimitiveTypeDescriptor) {
@@ -100,17 +179,37 @@ private String getDescription(
       }
     }
 
+    private String getParametersDescription(
+        ImmutableList<ParameterDescriptor> parameterDescriptors) {
+      return parameterDescriptors.stream()
+          .map(this::getDescription)
+          .collect(joining(", ", "(", ")"));
+    }
+
+    private String getTypeParameterDescription(TypeVariable typeVariable) {
+      return typeVariable.getName()
+          + " extends "
+          + getDescription(typeVariable.getUpperBoundTypeDescriptor());
+    }
+
+    private String getTypeParametersDescription(ImmutableList<TypeVariable> typeParameters) {
+      return inAngleBracketsIfNotEmpty(
+          typeParameters.stream().map(this::getTypeParameterDescription).collect(joining(", ")));
+    }
+
+    private String getTypeArgumentsDescription(ImmutableList<TypeDescriptor> typeArguments) {
+      return inAngleBracketsIfNotEmpty(
+          typeArguments.stream().map(this::getDescription).collect(joining(", ")));
+    }
+
     private String getTypeArgumentsDescription(
         DeclaredTypeDescriptor declaredTypeDescriptor,
         ImmutableList<TypeVariable> enclosingWildcardOrCaptures) {
       ImmutableList<TypeDescriptor> arguments = declaredTypeDescriptor.getTypeArgumentDescriptors();
-      if (arguments.isEmpty()) {
-        return "";
-      } else {
-        return arguments.stream()
-            .map(it -> getDescription(it, enclosingWildcardOrCaptures))
-            .collect(joining(", ", "<", ">"));
-      }
+      return inAngleBracketsIfNotEmpty(
+          arguments.stream()
+              .map(it -> getDescription(it, enclosingWildcardOrCaptures))
+              .collect(joining(", ")));
     }
 
     private String getDescriptionWithoutNullabilityAnnotation(
@@ -178,4 +277,12 @@ private static String getDescriptionInfix(NullabilityAnnotation nullabilityAnnot
       return description == null ? "" : " " + description + " ";
     }
   }
+
+  private static String appendSpaceIfNotEmpty(String string) {
+    return string.isEmpty() ? string : string + " ";
+  }
+
+  private static String inAngleBracketsIfNotEmpty(String string) {
+    return string.isEmpty() ? string : "<" + string + ">";
+  }
 }

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

@@ -85,15 +85,13 @@ public Expression rewriteTypeConversionContext(
                   return expression;
                 }
 
-                Describer describer = new Describer();
-                getProblems()
-                    .debug(
-                        getSourcePosition(),
-                        "Inserted nullability mismatch cast to '%s' because of assignment from '%s'"
-                            + " to '%s'",
-                        describer.getDescription(castTypeDescriptor),
-                        describer.getDescription(expression.getTypeDescriptor()),
-                        describer.getDescription(inferredTypeDescriptor));
+                debug(
+                    getSourcePosition(),
+                    "Inserted nullability mismatch cast to '%s' because of assignment from '%s'"
+                        + " to '%s'",
+                    getDescription(castTypeDescriptor),
+                    getDescription(expression.getTypeDescriptor()),
+                    getDescription(inferredTypeDescriptor));
 
                 return CastExpression.newBuilder()
                     .setExpression(expression)

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

@@ -72,7 +72,7 @@
  * }
  * }</pre>
  */
-public final class InsertQualifierProjectionCasts extends NormalizationPass {
+public final class InsertQualifierProjectionCasts extends AbstractJ2ktNormalizationPass {
   @Override
   public void applyTo(CompilationUnit compilationUnit) {
     // TODO(b/362477320): Consider switching to ConversionContextVisitor, once
@@ -99,6 +99,12 @@ private Expression projectExpression(Expression expression) {
               return expression;
             }
 
+            debug(
+                getSourcePosition(this),
+                "Inserting qualifier projection cast from %s to %s",
+                getDescription(typeDescriptor),
+                getDescription(projectedTypeDescriptor));
+
             return CastExpression.newBuilder()
                 .setExpression(expression)
                 .setCastTypeDescriptor(projectedTypeDescriptor)