fix importing inner class using string concat of outer field

We weren't aware that the compiler occasionally generates synthetic `access$123` methods that call constructors.
More precisely for the following constellation
```
class Outer {
  String field = "";
  class Inner {
    void concat() {
      field += "any";
    }
  }
}
```
the compiler generates bytecode instantiating and using a `StringBuilder`.
But for constructor calls the synthetic access resolution was not hooked in,
because we assumed that those methods would never call a constructor.
This in turn lead to the bug
```
java.lang.IllegalStateException: Never found a JavaCodeUnit that matches supposed origin CodeUnit{name='access$123'...
```
I.e. the method `access$123` was filtered out as synthetic,
but the origin of the constructor call had not been resolved to the actual `Inner.concat` method.

Signed-off-by: Peter Gafert <[email protected]>

archunit/src/main/java/com/tngtech/archunit/core/importer/ClassFileImportRecord.java

@@ -264,7 +264,7 @@ void forEachRawMethodCallRecord(Consumer<RawAccessRecord> doWithRecord) {
     }
 
     void forEachRawConstructorCallRecord(Consumer<RawAccessRecord> doWithRecord) {
-        resolveSyntheticOrigins(rawConstructorCallRecords, COPY_RAW_ACCESS_RECORD, syntheticLambdaAccessRecorder)
+        resolveSyntheticOrigins(rawConstructorCallRecords, COPY_RAW_ACCESS_RECORD, syntheticPrivateAccessRecorder, syntheticLambdaAccessRecorder)
                 .forEach(doWithRecord);
     }
 

archunit/src/test/java/com/tngtech/archunit/core/importer/ClassFileImporterSyntheticPrivateAccessesTest.java

@@ -5,13 +5,15 @@
 
 import com.tngtech.archunit.core.domain.JavaAccess;
 import com.tngtech.archunit.core.domain.JavaClass;
+import com.tngtech.archunit.core.domain.JavaFieldAccess;
 import org.junit.Test;
 
 import static com.tngtech.archunit.core.domain.JavaConstructor.CONSTRUCTOR_NAME;
 import static com.tngtech.archunit.core.domain.JavaFieldAccess.AccessType.GET;
 import static com.tngtech.archunit.core.domain.JavaFieldAccess.AccessType.SET;
 import static com.tngtech.archunit.testutil.Assertions.assertThatAccesses;
 import static com.tngtech.archunit.testutil.Assertions.expectedAccess;
+import static com.tngtech.archunit.testutil.assertion.AccessesAssertion.access;
 import static java.util.stream.Collectors.toSet;
 
 public class ClassFileImporterSyntheticPrivateAccessesTest {
@@ -422,6 +424,40 @@ Supplier<Supplier<Data_of_imports_private_constructor_reference_from_lambda.Targ
         );
     }
 
+    /**
+     * This is a special case, because for =+ concatenation of an outer string from an inner class
+     * the compiler creates a synthetic `access$123` method that creates a new `StringBuilder()`.
+     * Before this we wrongly assumed that all that happens from such `access$123` methods
+     * are field accesses and method calls, but no constructor calls.
+     */
+    @Test
+    public void imports_synthetic_access_from_string_concatenation() {
+        @SuppressWarnings("unused")
+        class Outer {
+            private String outerPrivateString = "Hello";
+
+            class Inner {
+                private void stringConcat() {
+                    outerPrivateString += ", world!";
+                }
+            }
+        }
+
+        Set<JavaFieldAccess> fieldAccesses = new ClassFileImporter().importClasses(Outer.class, Outer.Inner.class)
+                .get(Outer.Inner.class)
+                .getFieldAccessesFromSelf();
+
+        assertThatAccesses(fieldAccesses).contain(
+                access()
+                        .fromOrigin(Outer.Inner.class, "stringConcat")
+                        .toTarget(Outer.class, "outerPrivateString")
+                        .withAccessType(GET)).contain(
+                access()
+                        .fromOrigin(Outer.Inner.class, "stringConcat")
+                        .toTarget(Outer.class, "outerPrivateString")
+                        .withAccessType(SET));
+    }
+
     @SuppressWarnings("OptionalGetWithoutIsPresent")
     private Set<JavaAccess<?>> importRelevantAccesses(Class<?> origin, Class<?> target) {
         return new ClassFileImporter().importClasses(origin, target).get(origin).getMethods().stream()

archunit/src/test/java/com/tngtech/archunit/testutil/assertion/AccessesAssertion.java

@@ -7,6 +7,8 @@
 
 import com.tngtech.archunit.base.DescribedPredicate;
 import com.tngtech.archunit.core.domain.JavaAccess;
+import com.tngtech.archunit.core.domain.JavaFieldAccess;
+import com.tngtech.archunit.core.domain.JavaFieldAccess.AccessType;
 import org.assertj.core.api.Condition;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -35,7 +37,9 @@ public final AccessesAssertion containOnly(Condition<? super JavaAccess<?>>... c
         }
         assertThat(actualRemaining).as("Unexpected " + JavaAccess.class.getSimpleName()).isEmpty();
         return this;
-    }public static AccessCondition access() {
+    }
+
+    public static AccessCondition access() {
         return new AccessCondition();
     }
 
@@ -69,6 +73,15 @@ public AccessCondition toTarget(Class<?> owner, String name) {
                             .as("%s to target %s.%s", predicate.getDescription(), owner.getName(), name));
         }
 
+        public Condition<? super JavaAccess<?>> withAccessType(AccessType accessType) {
+            DescribedPredicate<JavaAccess<?>> withAccessType = DescribedPredicate.describe("", access ->
+                    access instanceof JavaFieldAccess
+                            && ((JavaFieldAccess) access).getAccessType().equals(accessType));
+            return new AccessCondition(
+                    predicate.and(withAccessType)
+                            .as("%s with access type %s", predicate.getDescription(), accessType));
+        }
+
         public AccessCondition declaredInLambda() {
             return new AccessCondition(
                     predicate.and(DescribedPredicate.describe("", JavaAccess::isDeclaredInLambda))