Merge pull request #12111 from smowton/smowton/feature/java-merge-classes-and-interfaces

Java: merge the @class and @interface database types and tables
2026-07-20 18:58:36 +02:00 · 2023-02-15 10:27:41 +00:00
parent 5f0b1973ee 62d10f91d8
commit 2cd1e09a7e
22 changed files with 35974 additions and 4363 deletions
--- a/java/downgrades/934bf10b4bd34cf648893efcd1d0d7be9471d39f/classes.ql
+++ b/java/downgrades/934bf10b4bd34cf648893efcd1d0d7be9471d39f/classes.ql
@@ -0,0 +1,11 @@
+class ClassOrInterface extends @classorinterface {
+  string toString() { result = "class-or-interface" }
+}
+
+class Package extends @package {
+  string toString() { result = "package" }
+}
+
+from ClassOrInterface id, string nodeName, Package parentId, ClassOrInterface sourceId
+where classes_or_interfaces(id, nodeName, parentId, sourceId) and not isInterface(id)
+select id, nodeName, parentId, sourceId
--- a/java/downgrades/934bf10b4bd34cf648893efcd1d0d7be9471d39f/interfaces.ql
+++ b/java/downgrades/934bf10b4bd34cf648893efcd1d0d7be9471d39f/interfaces.ql
@@ -0,0 +1,11 @@
+class ClassOrInterface extends @classorinterface {
+  string toString() { result = "class-or-interface" }
+}
+
+class Package extends @package {
+  string toString() { result = "package" }
+}
+
+from ClassOrInterface id, string nodeName, Package parentId, ClassOrInterface sourceId
+where classes_or_interfaces(id, nodeName, parentId, sourceId) and isInterface(id)
+select id, nodeName, parentId, sourceId
--- a/java/downgrades/934bf10b4bd34cf648893efcd1d0d7be9471d39f/old.dbscheme
+++ b/java/downgrades/934bf10b4bd34cf648893efcd1d0d7be9471d39f/old.dbscheme
--- a/java/downgrades/934bf10b4bd34cf648893efcd1d0d7be9471d39f/semmlecode.dbscheme
+++ b/java/downgrades/934bf10b4bd34cf648893efcd1d0d7be9471d39f/semmlecode.dbscheme
--- a/java/downgrades/934bf10b4bd34cf648893efcd1d0d7be9471d39f/upgrade.properties
+++ b/java/downgrades/934bf10b4bd34cf648893efcd1d0d7be9471d39f/upgrade.properties
@@ -0,0 +1,6 @@
+description: Seperate class and interface tables
+compatibility: full
+classes.rel: run classes.qlo
+interfaces.rel: run interfaces.qlo
+isInterface.rel: delete
+classes_or_interfaces.rel: delete
--- a/java/kotlin-extractor/src/main/kotlin/KotlinFileExtractor.kt
+++ b/java/kotlin-extractor/src/main/kotlin/KotlinFileExtractor.kt
@@ -351,18 +351,14 @@ open class KotlinFileExtractor(
            val pkgId = extractPackage(pkg)
            // TODO: There's lots of duplication between this and extractClassSource.
            // Can we share it?
+            val sourceId = useClassSource(c)
+            tw.writeClasses_or_interfaces(id, cls, pkgId, sourceId)
            if (c.isInterfaceLike) {
-                val interfaceId = id.cast<DbInterface>()
-                val sourceInterfaceId = useClassSource(c).cast<DbInterface>()
-                tw.writeInterfaces(interfaceId, cls, pkgId, sourceInterfaceId)
+                tw.writeIsInterface(id)
            } else {
-                val classId = id.cast<DbClass>()
-                val sourceClassId = useClassSource(c).cast<DbClass>()
-                tw.writeClasses(classId, cls, pkgId, sourceClassId)
-
                val kind = c.kind
                if (kind == ClassKind.ENUM_CLASS) {
-                    tw.writeIsEnumType(classId)
+                    tw.writeIsEnumType(id)
                } else if (kind != ClassKind.CLASS && kind != ClassKind.OBJECT && kind != ClassKind.ENUM_ENTRY) {
                    logger.errorElement("Unrecognised class kind $kind", c)
                }
@@ -459,11 +455,11 @@ open class KotlinFileExtractor(
    }

    private fun extractLocalTypeDeclStmt(c: IrClass, callable: Label<out DbCallable>, parent: Label<out DbStmtparent>, idx: Int) {
-        val id = extractClassSource(c, extractDeclarations = true, extractStaticInitializer = true, extractPrivateMembers = true, extractFunctionBodies = true).cast<DbClass>()
+        val id = extractClassSource(c, extractDeclarations = true, extractStaticInitializer = true, extractPrivateMembers = true, extractFunctionBodies = true)
        extractLocalTypeDeclStmt(id, c, callable, parent, idx)
    }

-    private fun extractLocalTypeDeclStmt(id: Label<out DbClass>, locElement: IrElement, callable: Label<out DbCallable>, parent: Label<out DbStmtparent>, idx: Int) {
+    private fun extractLocalTypeDeclStmt(id: Label<out DbClassorinterface>, locElement: IrElement, callable: Label<out DbCallable>, parent: Label<out DbStmtparent>, idx: Int) {
        val stmtId = tw.getFreshIdLabel<DbLocaltypedeclstmt>()
        tw.writeStmts_localtypedeclstmt(stmtId, parent, idx, callable)
        tw.writeIsLocalClassOrInterface(id, stmtId)
@@ -630,26 +626,22 @@ open class KotlinFileExtractor(
                val pkg = c.packageFqName?.asString() ?: ""
                val cls = if (c.isAnonymousObject) "" else c.name.asString()
                val pkgId = extractPackage(pkg)
+                tw.writeClasses_or_interfaces(id, cls, pkgId, id)
                if (c.isInterfaceLike) {
-                    val interfaceId = id.cast<DbInterface>()
-                    tw.writeInterfaces(interfaceId, cls, pkgId, interfaceId)
-
+                    tw.writeIsInterface(id)
                    if (c.kind == ClassKind.ANNOTATION_CLASS) {
-                        tw.writeIsAnnotType(interfaceId)
+                        tw.writeIsAnnotType(id)
                    }
                } else {
-                    val classId = id.cast<DbClass>()
-                    tw.writeClasses(classId, cls, pkgId, classId)
-
                    val kind = c.kind
                    if (kind == ClassKind.ENUM_CLASS) {
-                        tw.writeIsEnumType(classId)
+                        tw.writeIsEnumType(id)
                    } else if (kind != ClassKind.CLASS && kind != ClassKind.OBJECT && kind != ClassKind.ENUM_ENTRY) {
                        logger.warnElement("Unrecognised class kind $kind", c)
                    }

                    if (c.isData) {
-                        tw.writeKtDataClasses(classId)
+                        tw.writeKtDataClasses(id)
                    }
                }

@@ -694,7 +686,7 @@ open class KotlinFileExtractor(
                    tw.writeFieldsKotlinType(instance.id, type.kotlinResult.id)
                    tw.writeHasLocation(instance.id, locId)
                    addModifiers(instance.id, "public", "static", "final")
-                    tw.writeClass_object(id.cast<DbClass>(), instance.id)
+                    tw.writeClass_object(id, instance.id)
                }
                if (c.isObject) {
                    addModifiers(id, "static")
@@ -830,7 +822,7 @@ open class KotlinFileExtractor(
                            tw.writeFieldsKotlinType(instance.id, type.kotlinResult.id)
                            tw.writeHasLocation(instance.id, innerLocId)
                            addModifiers(instance.id, "public", "static", "final")
-                            tw.writeType_companion_object(parentId, instance.id, innerId.cast<DbClass>())
+                            tw.writeType_companion_object(parentId, instance.id, innerId)
                        }
                    }

@@ -4448,7 +4440,7 @@ open class KotlinFileExtractor(
    }

    private open inner class GeneratedClassHelper(protected val locId: Label<DbLocation>, protected val ids: GeneratedClassLabels) {
-        protected val classId = ids.type.javaResult.id.cast<DbClass>()
+        protected val classId = ids.type.javaResult.id.cast<DbClassorinterface>()

        /**
         * Extract a parameter to field assignment, such as `this.field = paramName` below:
@@ -4788,7 +4780,7 @@ open class KotlinFileExtractor(

            val locId = tw.getLocation(propertyReferenceExpr)

-            val javaResult = TypeResult(tw.getFreshIdLabel<DbClass>(), "", "")
+            val javaResult = TypeResult(tw.getFreshIdLabel<DbClassorinterface>(), "", "")
            val kotlinResult = TypeResult(tw.getFreshIdLabel<DbKt_notnull_type>(), "", "")
            tw.writeKt_notnull_types(kotlinResult.id, javaResult.id)
            val ids = GeneratedClassLabels(
@@ -4980,7 +4972,7 @@ open class KotlinFileExtractor(

            val locId = tw.getLocation(functionReferenceExpr)

-            val javaResult = TypeResult(tw.getFreshIdLabel<DbClass>(), "", "")
+            val javaResult = TypeResult(tw.getFreshIdLabel<DbClassorinterface>(), "", "")
            val kotlinResult = TypeResult(tw.getFreshIdLabel<DbKt_notnull_type>(), "", "")
            tw.writeKt_notnull_types(kotlinResult.id, javaResult.id)
            val ids = LocallyVisibleFunctionLabels(
@@ -5550,7 +5542,7 @@ open class KotlinFileExtractor(
                        return
                    }

-                    val javaResult = TypeResult(tw.getFreshIdLabel<DbClass>(), "", "")
+                    val javaResult = TypeResult(tw.getFreshIdLabel<DbClassorinterface>(), "", "")
                    val kotlinResult = TypeResult(tw.getFreshIdLabel<DbKt_notnull_type>(), "", "")
                    tw.writeKt_notnull_types(kotlinResult.id, javaResult.id)
                    val ids = LocallyVisibleFunctionLabels(
@@ -5659,7 +5651,7 @@ open class KotlinFileExtractor(

                    val idNewexpr = extractNewExpr(ids.constructor, ids.type, locId, id, 1, callable, enclosingStmt)

-                    tw.writeIsAnonymClass(ids.type.javaResult.id.cast<DbClass>(), idNewexpr)
+                    tw.writeIsAnonymClass(ids.type.javaResult.id.cast<DbClassorinterface>(), idNewexpr)

                    extractTypeAccessRecursive(e.typeOperand, locId, idNewexpr, -3, callable, enclosingStmt)

@@ -5705,11 +5697,11 @@ open class KotlinFileExtractor(
        compilerGeneratedKindOverride: CompilerGeneratedKinds? = null,
        superConstructorSelector: (IrFunction) -> Boolean = { it.valueParameters.isEmpty() },
        extractSuperconstructorArgs: (Label<DbSuperconstructorinvocationstmt>) -> Unit = {},
-    ): Label<out DbClass> {
+    ): Label<out DbClassorinterface> {
        // Write class
-        val id = ids.type.javaResult.id.cast<DbClass>()
+        val id = ids.type.javaResult.id.cast<DbClassorinterface>()
        val pkgId = extractPackage("")
-        tw.writeClasses(id, "", pkgId, id)
+        tw.writeClasses_or_interfaces(id, "", pkgId, id)
        tw.writeCompiler_generated(id, (compilerGeneratedKindOverride ?: CompilerGeneratedKinds.CALLABLE_CLASS).kind)
        tw.writeHasLocation(id, locId)

@@ -5761,7 +5753,7 @@ open class KotlinFileExtractor(
        localFunction: IrFunction,
        superTypes: List<IrType>,
        compilerGeneratedKindOverride: CompilerGeneratedKinds? = null
-    ) : Label<out DbClass> {
+    ) : Label<out DbClassorinterface> {
        with("generated class", localFunction) {
            val ids = getLocallyVisibleFunctionLabels(localFunction)

--- a/java/kotlin-extractor/src/main/kotlin/KotlinUsesExtractor.kt
+++ b/java/kotlin-extractor/src/main/kotlin/KotlinUsesExtractor.kt
@@ -71,16 +71,16 @@ open class KotlinUsesExtractor(
        TypeResult(fakeKotlinType(), "", "")
    )

-    fun extractFileClass(f: IrFile): Label<out DbClass> {
+    fun extractFileClass(f: IrFile): Label<out DbClassorinterface> {
        val pkg = f.fqName.asString()
        val jvmName = getFileClassName(f)
        val qualClassName = if (pkg.isEmpty()) jvmName else "$pkg.$jvmName"
        val label = "@\"class;$qualClassName\""
-        val id: Label<DbClass> = tw.getLabelFor(label) {
+        val id: Label<DbClassorinterface> = tw.getLabelFor(label) {
            val fileId = tw.mkFileId(f.path, false)
            val locId = tw.getWholeFileLocation(fileId)
            val pkgId = extractPackage(pkg)
-            tw.writeClasses(it, jvmName, pkgId, it)
+            tw.writeClasses_or_interfaces(it, jvmName, pkgId, it)
            tw.writeFile_class(it)
            tw.writeHasLocation(it, locId)

@@ -478,7 +478,7 @@ open class KotlinUsesExtractor(
    private fun useAnonymousClass(c: IrClass) =
        tw.lm.anonymousTypeMapping.getOrPut(c) {
            TypeResults(
-                TypeResult(tw.getFreshIdLabel<DbClass>(), "", ""),
+                TypeResult(tw.getFreshIdLabel<DbClassorinterface>(), "", ""),
                TypeResult(fakeKotlinType(), "TODO", "TODO")
            )
        }
@@ -487,8 +487,8 @@ open class KotlinUsesExtractor(
        val fakeKotlinPackageId: Label<DbPackage> = tw.getLabelFor("@\"FakeKotlinPackage\"", {
            tw.writePackages(it, "fake.kotlin")
        })
-        val fakeKotlinClassId: Label<DbClass> = tw.getLabelFor("@\"FakeKotlinClass\"", {
-            tw.writeClasses(it, "FakeKotlinClass", fakeKotlinPackageId, it)
+        val fakeKotlinClassId: Label<DbClassorinterface> = tw.getLabelFor("@\"FakeKotlinClass\"", {
+            tw.writeClasses_or_interfaces(it, "FakeKotlinClass", fakeKotlinPackageId, it)
        })
        val fakeKotlinTypeId: Label<DbKt_nullable_type> = tw.getLabelFor("@\"FakeKotlinType\"", {
            tw.writeKt_nullable_types(it, fakeKotlinClassId)
@@ -650,11 +650,11 @@ open class KotlinUsesExtractor(
        // We use this when we don't actually have an IrClass for a class
        // we want to refer to
        // TODO: Eliminate the need for this if possible
-        fun makeClass(pkgName: String, className: String): Label<DbClass> {
+        fun makeClass(pkgName: String, className: String): Label<DbClassorinterface> {
            val pkgId = extractPackage(pkgName)
            val label = "@\"class;$pkgName.$className\""
-            val classId: Label<DbClass> = tw.getLabelFor(label, {
-                tw.writeClasses(it, className, pkgId, it)
+            val classId: Label<DbClassorinterface> = tw.getLabelFor(label, {
+                tw.writeClasses_or_interfaces(it, className, pkgId, it)
            })
            return classId
        }
@@ -1237,7 +1237,7 @@ open class KotlinUsesExtractor(

        var res = tw.lm.locallyVisibleFunctionLabelMapping[f]
        if (res == null) {
-            val javaResult = TypeResult(tw.getFreshIdLabel<DbClass>(), "", "")
+            val javaResult = TypeResult(tw.getFreshIdLabel<DbClassorinterface>(), "", "")
            val kotlinResult = TypeResult(tw.getFreshIdLabel<DbKt_notnull_type>(), "", "")
            tw.writeKt_notnull_types(kotlinResult.id, javaResult.id)
            res = LocallyVisibleFunctionLabels(
--- a/java/ql/lib/config/semmlecode.dbscheme
+++ b/java/ql/lib/config/semmlecode.dbscheme
@@ -346,26 +346,26 @@ error_type(
  unique int id: @errortype
 );

-classes(
-  unique int id: @class,
+classes_or_interfaces(
+  unique int id: @classorinterface,
  string nodeName: string ref,
  int parentid: @package ref,
-  int sourceid: @class ref
+  int sourceid: @classorinterface ref
 );

 file_class(
-  int id: @class ref
+  int id: @classorinterface ref
 );

 class_object(
-  unique int id: @class ref,
+  unique int id: @classorinterface ref,
  unique int instance: @field ref
 );

 type_companion_object(
  unique int id: @classorinterface ref,
  unique int instance: @field ref,
-  unique int companion_object: @class ref
+  unique int companion_object: @classorinterface ref
 );

 kt_nullable_types(
@@ -386,15 +386,12 @@ kt_type_alias(

@kt_type = @kt_nullable_type | @kt_notnull_type

-isRecord(
-  unique int id: @class ref
+isInterface(
+  unique int id: @classorinterface ref
 );

-interfaces(
-  unique int id: @interface,
-  string nodeName: string ref,
-  int parentid: @package ref,
-  int sourceid: @interface ref
+isRecord(
+  unique int id: @classorinterface ref
 );

 fielddecls(
@@ -480,7 +477,7 @@ exceptions(
 );

 isAnnotType(
-  int interfaceid: @interface ref
+  int interfaceid: @classorinterface ref
 );

 isAnnotElem(
@@ -494,7 +491,7 @@ annotValue(
 );

 isEnumType(
-  int classid: @class ref
+  int classid: @classorinterface ref
 );

 isEnumConst(
@@ -546,7 +543,7 @@ erasure(

 #keyset[classid] #keyset[parent]
 isAnonymClass(
-  int classid: @class ref,
+  int classid: @classorinterface ref,
  int parent: @classinstancexpr ref
 );

@@ -586,7 +583,7 @@ extendsReftype(

 implInterface(
  int id1: @classorarray ref,
-  int id2: @interface ref
+  int id2: @classorinterface ref
 );

 permits(
@@ -868,7 +865,7 @@ propertyRefSetBinding(
  int setter: @callable ref
 );

-@exprparent = @stmt | @expr | @whenbranch | @callable | @field | @fielddecl | @class | @interface | @param | @localvar | @typevariable;
+@exprparent = @stmt | @expr | @whenbranch | @callable | @field | @fielddecl | @classorinterface | @param | @localvar | @typevariable;

 variableBinding(
  unique int expr: @varaccess ref,
@@ -1022,12 +1019,11 @@ javadocText(
@javadocParent = @javadoc | @javadocTag;
@javadocElement = @javadocTag | @javadocText;

-@classorinterface = @interface | @class;
@classorinterfaceorpackage = @classorinterface | @package;
@classorinterfaceorcallable = @classorinterface | @callable;
@boundedtype = @typevariable | @wildcard;
@reftype = @classorinterface | @array | @boundedtype | @errortype;
-@classorarray = @class | @array;
+@classorarray = @classorinterface | @array;
@type = @primitive | @reftype;
@callable = @method | @constructor;

@@ -1035,13 +1031,13 @@ javadocText(
@element = @package | @modifier | @annotation | @errortype |
           @locatableElement;

-@locatableElement = @file | @primitive | @class | @interface | @method | @constructor | @param | @exception | @field |
+@locatableElement = @file | @primitive | @classorinterface | @method | @constructor | @param | @exception | @field |
                    @boundedtype | @array | @localvar | @expr | @stmt | @import | @fielddecl | @kt_type | @kt_type_alias |
                    @kt_property;

@modifiable = @member_modifiable| @param | @localvar | @typevariable;

-@member_modifiable = @class | @interface | @method | @constructor | @field | @kt_property;
+@member_modifiable = @classorinterface | @method | @constructor | @field | @kt_property;

@member = @method | @constructor | @field | @reftype ;

@@ -1242,5 +1238,5 @@ ktFunctionOriginalNames(
 )

 ktDataClasses(
-  unique int id: @class ref
+  unique int id: @classorinterface ref
 )
--- a/java/ql/lib/config/semmlecode.dbscheme.stats
+++ b/java/ql/lib/config/semmlecode.dbscheme.stats
--- a/java/ql/lib/semmle/code/Location.qll
+++ b/java/ql/lib/semmle/code/Location.qll
@@ -10,9 +10,7 @@ private import semmle.code.SMAP

 /** Holds if element `e` has name `name`. */
 predicate hasName(Element e, string name) {
-  classes(e, name, _, _)
-  or
-  interfaces(e, name, _, _)
+  classes_or_interfaces(e, name, _, _)
  or
  primitives(e, name)
  or
--- a/java/ql/lib/semmle/code/java/Member.qll
+++ b/java/ql/lib/semmle/code/java/Member.qll
@@ -397,14 +397,21 @@ private predicate potentialInterfaceImplementationWithSignature(string sig, RefT
  not t.isAbstract()
 }

-pragma[nomagic]
-private predicate implementsInterfaceMethod(SrcMethod impl, SrcMethod m) {
-  exists(RefType t, Interface i, Method minst, Method implinst |
-    m = minst.getSourceDeclaration() and
+pragma[noinline]
+private predicate isInterfaceSourceImplementation(Method minst, RefType t) {
+  exists(Interface i |
    i = minst.getDeclaringType() and
    t.extendsOrImplements+(i) and
-    t.isSourceDeclaration() and
+    t.isSourceDeclaration()
+  )
+}
+
+pragma[nomagic]
+private predicate implementsInterfaceMethod(SrcMethod impl, SrcMethod m) {
+  exists(RefType t, Method minst, Method implinst |
+    isInterfaceSourceImplementation(minst, t) and
    potentialInterfaceImplementationWithSignature(minst.getSignature(), t, implinst) and
+    m = minst.getSourceDeclaration() and
    impl = implinst.getSourceDeclaration()
  )
 }
@@ -542,7 +549,7 @@ class Method extends Callable, @method {

 /** A method that is the same as its source declaration. */
 class SrcMethod extends Method {
-  SrcMethod() { methods(_, _, _, _, _, this) }
+  SrcMethod() { methods(this, _, _, _, _, this) }

  /**
   * All the methods that could possibly be called when this method
--- a/java/ql/lib/semmle/code/java/Type.qll
+++ b/java/ql/lib/semmle/code/java/Type.qll
@@ -385,10 +385,7 @@ class Array extends RefType, @array {
 */
 class RefType extends Type, Annotatable, Modifiable, @reftype {
  /** Gets the package in which this type is declared. */
-  Package getPackage() {
-    classes(this, _, result, _) or
-    interfaces(this, _, result, _)
-  }
+  Package getPackage() { classes_or_interfaces(this, _, result, _) }

  /** Gets the type in which this reference type is enclosed, if any. */
  RefType getEnclosingType() { enclInReftype(this, result) }
@@ -685,12 +682,12 @@ class SrcRefType extends RefType {
 }

 /** A class declaration. */
-class Class extends ClassOrInterface, @class {
+class Class extends ClassOrInterface {
+  Class() { not isInterface(this) }
+
  /** Holds if this class is an anonymous class. */
  predicate isAnonymous() { isAnonymClass(this.getSourceDeclaration(), _) }

-  override RefType getSourceDeclaration() { classes(this, _, _, result) }
-
  /**
   * Gets an annotation that applies to this class.
   *
@@ -742,10 +739,10 @@ class Record extends Class {
 }

 /** An intersection type. */
-class IntersectionType extends RefType, @class {
+class IntersectionType extends RefType, @classorinterface {
  IntersectionType() {
    exists(string shortname |
-      classes(this, shortname, _, _) and
+      classes_or_interfaces(this, shortname, _, _) and
      shortname.matches("% & ...")
    )
  }
@@ -842,7 +839,7 @@ class LocalClass extends LocalClassOrInterface, NestedClass {
 class TopLevelType extends RefType {
  TopLevelType() {
    not enclInReftype(this, _) and
-    (this instanceof Class or this instanceof Interface)
+    this instanceof ClassOrInterface
  }
 }

@@ -940,8 +937,8 @@ class InnerClass extends NestedClass {
 }

 /** An interface. */
-class Interface extends ClassOrInterface, @interface {
-  override RefType getSourceDeclaration() { interfaces(this, _, _, result) }
+class Interface extends ClassOrInterface {
+  Interface() { isInterface(this) }

  override predicate isAbstract() {
    // JLS 9.1.1.1: "Every interface is implicitly abstract"
@@ -953,6 +950,8 @@ class Interface extends ClassOrInterface, @interface {

 /** A class or interface. */
 class ClassOrInterface extends RefType, @classorinterface {
+  override RefType getSourceDeclaration() { classes_or_interfaces(this, _, _, result) }
+
  /** Holds if this class or interface is local. */
  predicate isLocal() { isLocalClassOrInterface(this.getSourceDeclaration(), _) }

--- a/java/ql/lib/semmle/code/java/dataflow/TypeFlow.qll
+++ b/java/ql/lib/semmle/code/java/dataflow/TypeFlow.qll
@@ -681,9 +681,14 @@ private predicate unionTypeFlow0(TypeFlowNode n, RefType t, boolean exact) {
 private predicate unionTypeFlow(TypeFlowNode n, RefType t, boolean exact) {
  unionTypeFlow0(n, t, exact) and
  // filter impossible union parts:
-  if exact = true
-  then t.getErasure().(RefType).getASourceSupertype*() = getTypeBound(n).getErasure()
-  else haveIntersection(getTypeBound(n), t)
+  exists(RefType tErased, RefType boundErased |
+    pragma[only_bind_into](tErased) = t.getErasure() and
+    pragma[only_bind_into](boundErased) = getTypeBound(n).getErasure()
+  |
+    if exact = true
+    then tErased.getASourceSupertype*() = boundErased
+    else erasedHaveIntersection(tErased, boundErased)
+  )
 }

 /**
--- a/java/ql/lib/semmle/code/java/dispatch/internal/Unification.qll
+++ b/java/ql/lib/semmle/code/java/dispatch/internal/Unification.qll
@@ -22,6 +22,17 @@ module MkUnification<unificationTarget/1 targetLeft, unificationTarget/1 targetR
    targetRight(t2) and t2.getGenericType() = g
  }

+  pragma[noinline]
+  private predicate unificationTargetsWithCommonSourceDecl(
+    ParameterizedType pt1, ParameterizedType pt2
+  ) {
+    exists(RefType commonSourceDecl |
+      unificationTargets(pt1, pt2) and
+      pragma[only_bind_out](pt1).getSourceDeclaration() = pragma[only_bind_out](commonSourceDecl) and
+      pragma[only_bind_out](pt2).getSourceDeclaration() = commonSourceDecl
+    )
+  }
+
  private predicate unificationTargets(Type t1, Type t2) {
    exists(GenericType g | unificationTargetLeft(t1, g) and unificationTargetRight(t2, g))
    or
@@ -32,10 +43,9 @@ module MkUnification<unificationTarget/1 targetLeft, unificationTarget/1 targetR
    )
    or
    exists(ParameterizedType pt1, ParameterizedType pt2, int pos |
-      unificationTargets(pt1, pt2) and
-      not pt1.getSourceDeclaration() != pt2.getSourceDeclaration() and
-      t1 = pt1.getTypeArgument(pos) and
-      t2 = pt2.getTypeArgument(pos)
+      unificationTargetsWithCommonSourceDecl(pt1, pt2) and
+      t1 = pt1.getTypeArgument(pragma[only_bind_into](pos)) and
+      t2 = pt2.getTypeArgument(pragma[only_bind_into](pos))
    )
  }

@@ -44,8 +54,8 @@ module MkUnification<unificationTarget/1 targetLeft, unificationTarget/1 targetR
    ParameterizedType t1, ParameterizedType t2, int pos, RefType arg1, RefType arg2
  ) {
    unificationTargets(t1, t2) and
-    arg1 = t1.getTypeArgument(pos) and
-    arg2 = t2.getTypeArgument(pos)
+    arg1 = t1.getTypeArgument(pragma[only_bind_into](pos)) and
+    arg2 = t2.getTypeArgument(pragma[only_bind_into](pos))
  }

  private RefType getUpperBound(RefType t) {
--- a/java/ql/lib/upgrades/44d61b266bebf261cb027872646262e645efa059/classes_or_interfaces.ql
+++ b/java/ql/lib/upgrades/44d61b266bebf261cb027872646262e645efa059/classes_or_interfaces.ql
@@ -0,0 +1,11 @@
+class ClassOrInterface extends @classorinterface {
+  string toString() { result = "class-or-interface" }
+}
+
+class Package extends @package {
+  string toString() { result = "package" }
+}
+
+from ClassOrInterface id, string nodeName, Package parentId, ClassOrInterface sourceId
+where classes(id, nodeName, parentId, sourceId) or interfaces(id, nodeName, parentId, sourceId)
+select id, nodeName, parentId, sourceId
--- a/java/ql/lib/upgrades/44d61b266bebf261cb027872646262e645efa059/isInterface.ql
+++ b/java/ql/lib/upgrades/44d61b266bebf261cb027872646262e645efa059/isInterface.ql
@@ -0,0 +1,6 @@
+class Interface extends @interface {
+  string toString() { result = "interface" }
+}
+
+from Interface i
+select i
--- a/java/ql/lib/upgrades/44d61b266bebf261cb027872646262e645efa059/old.dbscheme
+++ b/java/ql/lib/upgrades/44d61b266bebf261cb027872646262e645efa059/old.dbscheme
--- a/java/ql/lib/upgrades/44d61b266bebf261cb027872646262e645efa059/semmlecode.dbscheme
+++ b/java/ql/lib/upgrades/44d61b266bebf261cb027872646262e645efa059/semmlecode.dbscheme
--- a/java/ql/lib/upgrades/44d61b266bebf261cb027872646262e645efa059/semmlecode.dbscheme.stats
+++ b/java/ql/lib/upgrades/44d61b266bebf261cb027872646262e645efa059/semmlecode.dbscheme.stats
--- a/java/ql/lib/upgrades/44d61b266bebf261cb027872646262e645efa059/upgrade.properties
+++ b/java/ql/lib/upgrades/44d61b266bebf261cb027872646262e645efa059/upgrade.properties
@@ -0,0 +1,6 @@
+description: Merge class and interface tables
+compatibility: full
+classes_or_interfaces.rel: run classes_or_interfaces.qlo
+isInterface.rel: run isInterface.qlo
+classes.rel: delete
+interfaces.rel: delete
--- a/java/ql/src/utils/stub-generator/Stubs.qll
+++ b/java/ql/src/utils/stub-generator/Stubs.qll
@@ -515,7 +515,7 @@ private RefType getAReferencedType(RefType t) {

 /** A top level type whose file should be stubbed */
 class GeneratedTopLevel extends TopLevelType instanceof GeneratedType {
-  GeneratedTopLevel() { this = this.getSourceDeclaration() }
+  GeneratedTopLevel() { this = this.(ClassOrInterface).getSourceDeclaration() }

  private TopLevelType getAnImportedType() {
    result = getAReferencedType(this).getSourceDeclaration() and
@@ -523,9 +523,8 @@ class GeneratedTopLevel extends TopLevelType instanceof GeneratedType {
  }

  private string stubAnImport() {
-    exists(RefType t, string pkg, string name |
+    exists(ClassOrInterface t, string pkg, string name |
      t = this.getAnImportedType() and
-      (t instanceof Class or t instanceof Interface) and
      t.hasQualifiedName(pkg, name) and
      t != this and
      pkg != "java.lang"
--- a/java/ql/test/library-tests/qlengine/selectAtType.ql
+++ b/java/ql/test/library-tests/qlengine/selectAtType.ql
@@ -1,5 +1,5 @@
 import java

-@class clasz() { any() }
+@classorinterface clasz() { any() }

 select clasz()