Internal change enabling kotlin stack trace demangling.

core/src/com/google/inject/internal/KotlinSupport.java

@@ -79,5 +79,10 @@ public boolean isValueClass(Class<?> clazz) {
     public boolean isKotlinClass(Class<?> clazz) {
       return false;
     }
+
+    @Override
+    public StackTraceElement maybeDemangleSTE(StackTraceElement element, Class<?> clazz) {
+      return element;
+    }
   }
 }

core/src/com/google/inject/internal/KotlinSupportInterface.java

@@ -36,4 +36,10 @@ public interface KotlinSupportInterface {
 
   /** Returns whether the {@code clazz} is a Kotlin class. */
   boolean isKotlinClass(Class<?> clazz);
+
+  /**
+   * Returns a demangled StackTraceElement if it corresponds to an inlined Kotlin function,
+   * otherwise returns the original StackTraceElement.
+   */
+  StackTraceElement maybeDemangleSTE(StackTraceElement element, Class<?> clazz);
 }

core/src/com/google/inject/internal/util/CallerFinder.java

@@ -7,5 +7,19 @@
  * for implementing it.
  */
 interface CallerFinder {
-  StackTraceElement findCaller(Predicate<String> shouldBeSkipped);
+  /**
+   * A Tuple to hold the stack element alongside the class it originated from if StackWalker
+   * captured it.
+   */
+  final class Caller {
+    final StackTraceElement element;
+    final Class<?> clazz;
+
+    Caller(StackTraceElement element, Class<?> clazz) {
+      this.element = element;
+      this.clazz = clazz;
+    }
+  }
+
+  Caller findCaller(Predicate<String> shouldBeSkipped);
 }

core/src/com/google/inject/internal/util/DirectStackWalkerFinder.java

@@ -8,10 +8,10 @@ final class DirectStackWalkerFinder implements CallerFinder {
       StackWalker.getInstance(StackWalker.Option.RETAIN_CLASS_REFERENCE);
 
   @Override
-  public StackTraceElement findCaller(Predicate<String> shouldBeSkipped) {
+  public CallerFinder.Caller findCaller(Predicate<String> shouldBeSkipped) {
     return WALKER
         .walk(s -> s.skip(2).filter(f -> !shouldBeSkipped.test(f.getClassName())).findFirst())
-        .map(StackWalker.StackFrame::toStackTraceElement)
+        .map(f -> new CallerFinder.Caller(f.toStackTraceElement(), f.getDeclaringClass()))
         .orElseThrow(AssertionError::new);
   }
 }

core/src/com/google/inject/internal/util/NewThrowableFinder.java

@@ -5,12 +5,12 @@
 /** A CallerFinder that construcst a new Throwable and iterates through its stack trace. */
 class NewThrowableFinder implements CallerFinder {
   @Override
-  public StackTraceElement findCaller(Predicate<String> shouldBeSkipped) {
+  public CallerFinder.Caller findCaller(Predicate<String> shouldBeSkipped) {
     StackTraceElement[] stackTraceElements = new Throwable().getStackTrace();
     for (StackTraceElement element : stackTraceElements) {
       String className = element.getClassName();
       if (!shouldBeSkipped.test(className)) {
-        return element;
+        return new CallerFinder.Caller(element, /* clazz= */ null);
       }
     }
     throw new AssertionError();

core/src/com/google/inject/internal/util/SourceProvider.java

@@ -19,6 +19,7 @@
 import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Lists;
+import com.google.inject.internal.KotlinSupport;
 import java.util.List;
 
 /**
@@ -81,7 +82,8 @@ private static List<String> asStrings(Class<?>... classes) {
    * is not skipped.
    */
   public StackTraceElement getCaller() {
-    return FINDER.findCaller(this::shouldBeSkipped);
+    CallerFinder.Caller caller = FINDER.findCaller(this::shouldBeSkipped);
+    return KotlinSupport.getInstance().maybeDemangleSTE(caller.element, caller.clazz);
   }
 
   /** Returns the non-skipped module class name. */