diff --git a/prometeu-compiler/frontends/prometeu-frontend-pbs/src/main/java/p/studio/compiler/pbs/PbsFrontendCompiler.java b/prometeu-compiler/frontends/prometeu-frontend-pbs/src/main/java/p/studio/compiler/pbs/PbsFrontendCompiler.java
index 25e52f41..3286f13d 100644
--- a/prometeu-compiler/frontends/prometeu-frontend-pbs/src/main/java/p/studio/compiler/pbs/PbsFrontendCompiler.java
+++ b/prometeu-compiler/frontends/prometeu-frontend-pbs/src/main/java/p/studio/compiler/pbs/PbsFrontendCompiler.java
@@ -360,7 +360,6 @@ public final class PbsFrontendCompiler {
             final var callableShapeId = callableShapeId(declaredFn, typeSurfaceTable, callableShapeTable);
             final var callableId = callableIdTable.register(
                     normalizedModuleId,
-                    normalizedModuleKey,
                     declaredCallable.callableName(),
                     declaredFn.parameters().size(),
                     callableShapeSurface(callableShapeId, typeSurfaceTable, callableShapeTable));
@@ -376,7 +375,6 @@ public final class PbsFrontendCompiler {
         for (final var importedCallable : importedCallables) {
             final var callableId = callableIdTable.register(
                     importedCallable.moduleId(),
-                    importedCallable.moduleKey(),
                     importedCallable.callableName(),
                     importedCallable.arity(),
                     importedCallable.shapeSurface());
@@ -425,7 +423,6 @@ public final class PbsFrontendCompiler {
                 instructions.add(new IRBackendExecutableFunction.Instruction(
                         IRBackendExecutableFunction.InstructionKind.RET,
                         "",
-                        "",
                         null,
                         null,
                         null,
@@ -451,7 +448,6 @@ public final class PbsFrontendCompiler {
             executableFunctions.add(new IRBackendExecutableFunction(
                     fileId,
                     normalizedModuleId,
-                    normalizedModuleKey,
                     callable.callableName(),
                     functionCallableId,
                     start,
@@ -670,7 +666,6 @@ public final class PbsFrontendCompiler {
                 context.instructions().add(new IRBackendExecutableFunction.Instruction(
                         IRBackendExecutableFunction.InstructionKind.RET,
                         "",
-                        "",
                         null,
                         null,
                         null,
@@ -926,7 +921,6 @@ public final class PbsFrontendCompiler {
             context.instructions().add(new IRBackendExecutableFunction.Instruction(
                     IRBackendExecutableFunction.InstructionKind.CALL_HOST,
                     "",
-                    "",
                     new IRBackendExecutableFunction.HostCallMetadata(
                             host.abiModule(),
                             host.abiMethod(),
@@ -948,7 +942,6 @@ public final class PbsFrontendCompiler {
             context.instructions().add(new IRBackendExecutableFunction.Instruction(
                     IRBackendExecutableFunction.InstructionKind.CALL_INTRINSIC,
                     "",
-                    "",
                     null,
                     new IRBackendExecutableFunction.IntrinsicCallMetadata(
                             intrinsic.canonicalName(),
@@ -977,7 +970,6 @@ public final class PbsFrontendCompiler {
         context.instructions().add(new IRBackendExecutableFunction.Instruction(
                 IRBackendExecutableFunction.InstructionKind.CALL_FUNC,
                 calleeSignature.moduleId(),
-                calleeSignature.moduleKey(),
                 calleeSignature.callableName(),
                 calleeCallableId,
                 null,
@@ -1127,7 +1119,7 @@ public final class PbsFrontendCompiler {
             final ExecutableLoweringContext context) {
         context.instructions().add(new IRBackendExecutableFunction.Instruction(
                 jumpKind,
-                "",
+                ModuleId.none(),
                 "",
                 null,
                 null,
@@ -1145,7 +1137,7 @@ public final class PbsFrontendCompiler {
             final ExecutableLoweringContext context) {
         context.instructions().add(new IRBackendExecutableFunction.Instruction(
                 IRBackendExecutableFunction.InstructionKind.LABEL,
-                "",
+                ModuleId.none(),
                 "",
                 null,
                 null,
@@ -1163,7 +1155,7 @@ public final class PbsFrontendCompiler {
             final ExecutableLoweringContext context) {
         context.instructions().add(new IRBackendExecutableFunction.Instruction(
                 IRBackendExecutableFunction.InstructionKind.PUSH_I32,
-                "",
+                ModuleId.none(),
                 "",
                 null,
                 null,
@@ -1181,7 +1173,7 @@ public final class PbsFrontendCompiler {
             final ExecutableLoweringContext context) {
         context.instructions().add(new IRBackendExecutableFunction.Instruction(
                 IRBackendExecutableFunction.InstructionKind.PUSH_CONST,
-                "",
+                ModuleId.none(),
                 "",
                 null,
                 null,
@@ -1199,7 +1191,7 @@ public final class PbsFrontendCompiler {
             final ExecutableLoweringContext context) {
         context.instructions().add(new IRBackendExecutableFunction.Instruction(
                 IRBackendExecutableFunction.InstructionKind.GET_LOCAL,
-                "",
+                ModuleId.none(),
                 "",
                 null,
                 null,
diff --git a/prometeu-compiler/frontends/prometeu-frontend-pbs/src/test/java/p/studio/compiler/pbs/PbsGoldenArtifactsTest.java b/prometeu-compiler/frontends/prometeu-frontend-pbs/src/test/java/p/studio/compiler/pbs/PbsGoldenArtifactsTest.java
index 5a03007d..2e087cc3 100644
--- a/prometeu-compiler/frontends/prometeu-frontend-pbs/src/test/java/p/studio/compiler/pbs/PbsGoldenArtifactsTest.java
+++ b/prometeu-compiler/frontends/prometeu-frontend-pbs/src/test/java/p/studio/compiler/pbs/PbsGoldenArtifactsTest.java
@@ -46,7 +46,7 @@ class PbsGoldenArtifactsTest {
             final var callable = file.callableSignatures().get(i);
             out.append(i)
                     .append(':')
-                    .append(callable.moduleKey())
+                    .append(callable.moduleId().isNone() ? "-" : callable.moduleId().getIndex())
                     .append("::")
                     .append(callable.callableName())
                     .append('/')
@@ -61,7 +61,7 @@ class PbsGoldenArtifactsTest {
             out.append("fn#")
                     .append(i)
                     .append(':')
-                    .append(fn.moduleKey())
+                    .append(fn.moduleId().isNone() ? "-" : fn.moduleId().getIndex())
                     .append("::")
                     .append(fn.callableName())
                     .append(" id=")
diff --git a/prometeu-compiler/frontends/prometeu-frontend-pbs/src/test/java/p/studio/compiler/services/PBSFrontendPhaseServiceTest.java b/prometeu-compiler/frontends/prometeu-frontend-pbs/src/test/java/p/studio/compiler/services/PBSFrontendPhaseServiceTest.java
index a771f26f..c0ccf6a9 100644
--- a/prometeu-compiler/frontends/prometeu-frontend-pbs/src/test/java/p/studio/compiler/services/PBSFrontendPhaseServiceTest.java
+++ b/prometeu-compiler/frontends/prometeu-frontend-pbs/src/test/java/p/studio/compiler/services/PBSFrontendPhaseServiceTest.java
@@ -211,7 +211,6 @@ class PBSFrontendPhaseServiceTest {
 
         assertNotNull(callInstruction.calleeModuleId());
         assertEquals(targetFn.moduleId().getIndex(), callInstruction.calleeModuleId().getIndex());
-        assertEquals(targetFn.moduleKey(), callInstruction.calleeModuleKey());
         assertTrue(callerFn.moduleId().getIndex() != callInstruction.calleeModuleId().getIndex());
     }
 
@@ -916,7 +915,8 @@ class PBSFrontendPhaseServiceTest {
                 .filter(function -> "frame".equals(function.callableName()))
                 .findFirst();
         final var executableNames = irBackend.getExecutableFunctions().stream()
-                .map(function -> function.callableName() + "@" + function.moduleKey())
+                .map(function -> function.callableName() + "@"
+                        + (function.moduleId().isNone() ? "-" : function.moduleId().getIndex()))
                 .toList();
         assertTrue(
                 frameExecutableOptional.isPresent(),
diff --git a/prometeu-compiler/frontends/prometeu-frontend-pbs/src/test/resources/golden/frontend-irbackend.txt b/prometeu-compiler/frontends/prometeu-frontend-pbs/src/test/resources/golden/frontend-irbackend.txt
index a43f9cb2..4ff905e1 100644
--- a/prometeu-compiler/frontends/prometeu-frontend-pbs/src/test/resources/golden/frontend-irbackend.txt
+++ b/prometeu-compiler/frontends/prometeu-frontend-pbs/src/test/resources/golden/frontend-irbackend.txt
@@ -1,11 +1,11 @@
 callables=2
-0:::b/1|(simple:int)->simple:int
-1:::a/0|()->simple:int
+0:-::b/1|(simple:int)->simple:int
+1:-::a/0|()->simple:int
 intrinsics=0
-fn#0:::b id=0
+fn#0:-::b id=0
   GET_LOCAL calleeId=- intrinsicId=-
   RET calleeId=- intrinsicId=-
-fn#1:::a id=1
+fn#1:-::a id=1
   PUSH_I32 calleeId=- intrinsicId=-
   CALL_FUNC calleeId=0 intrinsicId=-
   RET calleeId=- intrinsicId=-
diff --git a/prometeu-compiler/prometeu-build-pipeline/src/main/java/p/studio/compiler/backend/irvm/LowerToIRVMService.java b/prometeu-compiler/prometeu-build-pipeline/src/main/java/p/studio/compiler/backend/irvm/LowerToIRVMService.java
index 05710baf..075f0c87 100644
--- a/prometeu-compiler/prometeu-build-pipeline/src/main/java/p/studio/compiler/backend/irvm/LowerToIRVMService.java
+++ b/prometeu-compiler/prometeu-build-pipeline/src/main/java/p/studio/compiler/backend/irvm/LowerToIRVMService.java
@@ -299,8 +299,8 @@ public class LowerToIRVMService {
         final var entryPointModuleId = backend.getEntryPointModuleId();
         final var sorted = new ArrayList<>(backend.getExecutableFunctions().asList());
         sorted.sort((left, right) -> {
-            final var leftModuleKey = moduleSortKey(backend, left.moduleId(), left.moduleKey());
-            final var rightModuleKey = moduleSortKey(backend, right.moduleId(), right.moduleKey());
+            final var leftModuleKey = moduleSortKey(backend, left.moduleId());
+            final var rightModuleKey = moduleSortKey(backend, right.moduleId());
             final var moduleCmp = leftModuleKey.compareTo(rightModuleKey);
             if (moduleCmp != 0) {
                 return moduleCmp;
@@ -367,15 +367,14 @@ public class LowerToIRVMService {
 
     private String moduleSortKey(
             final IRBackend backend,
-            final ModuleId moduleId,
-            final String fallbackModuleKey) {
+            final ModuleId moduleId) {
         if (moduleId != null && !moduleId.isNone()) {
             final var index = moduleId.getIndex();
             if (index >= 0 && index < backend.getModulePool().size()) {
                 return canonicalModuleSortKey(backend.getModulePool().get(index));
             }
         }
-        return fallbackModuleKey == null ? "" : fallbackModuleKey;
+        return "";
     }
 
     private String canonicalModuleSortKey(final ModuleReference reference) {
diff --git a/prometeu-compiler/prometeu-build-pipeline/src/test/java/p/studio/compiler/backend/GoldenArtifactsTest.java b/prometeu-compiler/prometeu-build-pipeline/src/test/java/p/studio/compiler/backend/GoldenArtifactsTest.java
index 45292ae6..0b39f615 100644
--- a/prometeu-compiler/prometeu-build-pipeline/src/test/java/p/studio/compiler/backend/GoldenArtifactsTest.java
+++ b/prometeu-compiler/prometeu-build-pipeline/src/test/java/p/studio/compiler/backend/GoldenArtifactsTest.java
@@ -45,7 +45,6 @@ class GoldenArtifactsTest {
         return IRBackend.builder()
                 .executableFunctions(ReadOnlyList.from(new IRBackendExecutableFunction(
                         new FileId(1),
-                        "app/main",
                         "main",
                         new CallableId(0),
                         0,
@@ -58,15 +57,12 @@ class GoldenArtifactsTest {
                                 new IRBackendExecutableFunction.Instruction(
                                         IRBackendExecutableFunction.InstructionKind.CALL_HOST,
                                         "",
-                                        "",
-                                        null,
                                         new IRBackendExecutableFunction.HostCallMetadata("gfx", "draw_pixel", 1, 0, 0),
                                         null,
                                         Span.none()),
                                 new IRBackendExecutableFunction.Instruction(
                                         IRBackendExecutableFunction.InstructionKind.CALL_INTRINSIC,
                                         "",
-                                        "",
                                         null,
                                         new IRBackendExecutableFunction.IntrinsicCallMetadata("input.pad", 1, new IntrinsicId(0)),
                                         0,
@@ -75,7 +71,6 @@ class GoldenArtifactsTest {
                                 new IRBackendExecutableFunction.Instruction(
                                         IRBackendExecutableFunction.InstructionKind.RET,
                                         "",
-                                        "",
                                         null,
                                         null,
                                         Span.none())),
diff --git a/prometeu-compiler/prometeu-build-pipeline/src/test/java/p/studio/compiler/backend/irvm/LowerToIRVMServiceTest.java b/prometeu-compiler/prometeu-build-pipeline/src/test/java/p/studio/compiler/backend/irvm/LowerToIRVMServiceTest.java
index 95084e37..6f1271c6 100644
--- a/prometeu-compiler/prometeu-build-pipeline/src/test/java/p/studio/compiler/backend/irvm/LowerToIRVMServiceTest.java
+++ b/prometeu-compiler/prometeu-build-pipeline/src/test/java/p/studio/compiler/backend/irvm/LowerToIRVMServiceTest.java
@@ -264,7 +264,6 @@ class LowerToIRVMServiceTest {
             final ReadOnlyList<IRBackendExecutableFunction.Instruction> instructions) {
         return new IRBackendExecutableFunction(
                 new FileId(0),
-                moduleKey,
                 name,
                 new CallableId(callableId),
                 0,
@@ -296,7 +295,6 @@ class LowerToIRVMServiceTest {
         return new IRBackendExecutableFunction(
                 new FileId(0),
                 new ModuleId(moduleId),
-                moduleKey,
                 name,
                 new CallableId(callableId),
                 0,
@@ -313,7 +311,6 @@ class LowerToIRVMServiceTest {
         return new IRBackendExecutableFunction.Instruction(
                 IRBackendExecutableFunction.InstructionKind.RET,
                 "",
-                "",
                 null,
                 null,
                 Span.none());
@@ -325,7 +322,7 @@ class LowerToIRVMServiceTest {
             final int calleeCallableId) {
         return new IRBackendExecutableFunction.Instruction(
                 IRBackendExecutableFunction.InstructionKind.CALL_FUNC,
-                moduleKey,
+                ModuleId.none(),
                 name,
                 new CallableId(calleeCallableId),
                 null,
@@ -341,7 +338,7 @@ class LowerToIRVMServiceTest {
             final int expectedRetSlots) {
         return new IRBackendExecutableFunction.Instruction(
                 IRBackendExecutableFunction.InstructionKind.CALL_FUNC,
-                moduleKey,
+                ModuleId.none(),
                 name,
                 new CallableId(calleeCallableId),
                 null,
@@ -360,7 +357,6 @@ class LowerToIRVMServiceTest {
         return new IRBackendExecutableFunction.Instruction(
                 IRBackendExecutableFunction.InstructionKind.CALL_HOST,
                 "",
-                "",
                 new IRBackendExecutableFunction.HostCallMetadata(module, name, version, argSlots, retSlots),
                 null,
                 Span.none());
@@ -373,7 +369,6 @@ class LowerToIRVMServiceTest {
         return new IRBackendExecutableFunction.Instruction(
                 IRBackendExecutableFunction.InstructionKind.CALL_INTRINSIC,
                 "",
-                "",
                 null,
                 new IRBackendExecutableFunction.IntrinsicCallMetadata(canonicalName, canonicalVersion, new IntrinsicId(intrinsicId)),
                 0,
@@ -384,7 +379,7 @@ class LowerToIRVMServiceTest {
     private static IRBackendExecutableFunction.Instruction label(final String label) {
         return new IRBackendExecutableFunction.Instruction(
                 IRBackendExecutableFunction.InstructionKind.LABEL,
-                "",
+                ModuleId.none(),
                 "",
                 null,
                 null,
@@ -399,7 +394,7 @@ class LowerToIRVMServiceTest {
     private static IRBackendExecutableFunction.Instruction jmp(final String target) {
         return new IRBackendExecutableFunction.Instruction(
                 IRBackendExecutableFunction.InstructionKind.JMP,
-                "",
+                ModuleId.none(),
                 "",
                 null,
                 null,
diff --git a/prometeu-compiler/prometeu-build-pipeline/src/test/java/p/studio/compiler/backend/irvm/OptimizeIRVMEquivalenceHarnessTest.java b/prometeu-compiler/prometeu-build-pipeline/src/test/java/p/studio/compiler/backend/irvm/OptimizeIRVMEquivalenceHarnessTest.java
index 57e44223..4c5ceec5 100644
--- a/prometeu-compiler/prometeu-build-pipeline/src/test/java/p/studio/compiler/backend/irvm/OptimizeIRVMEquivalenceHarnessTest.java
+++ b/prometeu-compiler/prometeu-build-pipeline/src/test/java/p/studio/compiler/backend/irvm/OptimizeIRVMEquivalenceHarnessTest.java
@@ -322,7 +322,6 @@ class OptimizeIRVMEquivalenceHarnessTest {
             final ReadOnlyList<IRBackendExecutableFunction.Instruction> instructions) {
         return new IRBackendExecutableFunction(
                 new FileId(1),
-                "app",
                 name,
                 new CallableId(callableId),
                 0,
@@ -339,8 +338,6 @@ class OptimizeIRVMEquivalenceHarnessTest {
         return new IRBackendExecutableFunction.Instruction(
                 IRBackendExecutableFunction.InstructionKind.RET,
                 "",
-                "",
-                null,
                 null,
                 null,
                 Span.none());
@@ -355,8 +352,6 @@ class OptimizeIRVMEquivalenceHarnessTest {
         return new IRBackendExecutableFunction.Instruction(
                 IRBackendExecutableFunction.InstructionKind.CALL_HOST,
                 "",
-                "",
-                null,
                 new IRBackendExecutableFunction.HostCallMetadata(module, name, version, argSlots, retSlots),
                 null,
                 Span.none());
@@ -371,7 +366,6 @@ class OptimizeIRVMEquivalenceHarnessTest {
         return new IRBackendExecutableFunction.Instruction(
                 IRBackendExecutableFunction.InstructionKind.CALL_INTRINSIC,
                 "",
-                "",
                 null,
                 null,
                 new IRBackendExecutableFunction.IntrinsicCallMetadata(canonicalName, canonicalVersion, new IntrinsicId(intrinsicId)),
diff --git a/prometeu-compiler/prometeu-build-pipeline/src/test/java/p/studio/compiler/integration/BackendGateIIntegrationTest.java b/prometeu-compiler/prometeu-build-pipeline/src/test/java/p/studio/compiler/integration/BackendGateIIntegrationTest.java
index 6e1c2a23..236bd152 100644
--- a/prometeu-compiler/prometeu-build-pipeline/src/test/java/p/studio/compiler/integration/BackendGateIIntegrationTest.java
+++ b/prometeu-compiler/prometeu-build-pipeline/src/test/java/p/studio/compiler/integration/BackendGateIIntegrationTest.java
@@ -188,7 +188,6 @@ class BackendGateIIntegrationTest {
             final ReadOnlyList<IRBackendExecutableFunction.Instruction> instructions) {
         return new IRBackendExecutableFunction(
                 new FileId(1),
-                "app/main",
                 name,
                 new CallableId(1),
                 0,
@@ -205,7 +204,6 @@ class BackendGateIIntegrationTest {
         return new IRBackendExecutableFunction.Instruction(
                 IRBackendExecutableFunction.InstructionKind.RET,
                 "",
-                "",
                 null,
                 null,
                 Span.none());
@@ -220,7 +218,6 @@ class BackendGateIIntegrationTest {
         return new IRBackendExecutableFunction.Instruction(
                 IRBackendExecutableFunction.InstructionKind.CALL_HOST,
                 "",
-                "",
                 new IRBackendExecutableFunction.HostCallMetadata(module, name, version, argSlots, retSlots),
                 null,
                 Span.none());
@@ -233,7 +230,6 @@ class BackendGateIIntegrationTest {
         return new IRBackendExecutableFunction.Instruction(
                 IRBackendExecutableFunction.InstructionKind.CALL_INTRINSIC,
                 "",
-                "",
                 null,
                 new IRBackendExecutableFunction.IntrinsicCallMetadata(canonicalName, canonicalVersion, new IntrinsicId(intrinsicId)),
                 0,
diff --git a/prometeu-compiler/prometeu-build-pipeline/src/test/java/p/studio/compiler/workspaces/stages/BackendSafetyGateSUTest.java b/prometeu-compiler/prometeu-build-pipeline/src/test/java/p/studio/compiler/workspaces/stages/BackendSafetyGateSUTest.java
index 2b8f4f94..09f776f3 100644
--- a/prometeu-compiler/prometeu-build-pipeline/src/test/java/p/studio/compiler/workspaces/stages/BackendSafetyGateSUTest.java
+++ b/prometeu-compiler/prometeu-build-pipeline/src/test/java/p/studio/compiler/workspaces/stages/BackendSafetyGateSUTest.java
@@ -28,7 +28,6 @@ class BackendSafetyGateSUTest {
         final var backend = IRBackend.builder()
                 .executableFunctions(ReadOnlyList.from(new IRBackendExecutableFunction(
                         new FileId(1),
-                        "app",
                         "main",
                         new CallableId(1),
                         0,
@@ -40,7 +39,7 @@ class BackendSafetyGateSUTest {
                         ReadOnlyList.from(
                                 new IRBackendExecutableFunction.Instruction(
                                         IRBackendExecutableFunction.InstructionKind.CALL_FUNC,
-                                        "app",
+                                        p.studio.compiler.source.identifiers.ModuleId.none(),
                                         "missing",
                                         new CallableId(99),
                                         null,
@@ -51,7 +50,6 @@ class BackendSafetyGateSUTest {
                                 new IRBackendExecutableFunction.Instruction(
                                         IRBackendExecutableFunction.InstructionKind.RET,
                                         "",
-                                        "",
                                         null,
                                         null,
                                         Span.none())),
@@ -113,7 +111,6 @@ class BackendSafetyGateSUTest {
         final var backend = IRBackend.builder()
                 .executableFunctions(ReadOnlyList.from(new IRBackendExecutableFunction(
                         new FileId(1),
-                        "app",
                         "main",
                         new CallableId(1),
                         0,
@@ -125,7 +122,6 @@ class BackendSafetyGateSUTest {
                         ReadOnlyList.from(new IRBackendExecutableFunction.Instruction(
                                 IRBackendExecutableFunction.InstructionKind.RET,
                                 "",
-                                "",
                                 null,
                                 null,
                                 Span.none())),
diff --git a/prometeu-compiler/prometeu-build-pipeline/src/test/java/p/studio/compiler/workspaces/stages/LowerToIRVMPipelineStageTest.java b/prometeu-compiler/prometeu-build-pipeline/src/test/java/p/studio/compiler/workspaces/stages/LowerToIRVMPipelineStageTest.java
index 13562bd3..db1f4390 100644
--- a/prometeu-compiler/prometeu-build-pipeline/src/test/java/p/studio/compiler/workspaces/stages/LowerToIRVMPipelineStageTest.java
+++ b/prometeu-compiler/prometeu-build-pipeline/src/test/java/p/studio/compiler/workspaces/stages/LowerToIRVMPipelineStageTest.java
@@ -38,7 +38,6 @@ class LowerToIRVMPipelineStageTest {
         ctx.irBackend = IRBackend.builder()
                 .executableFunctions(ReadOnlyList.from(new IRBackendExecutableFunction(
                         new FileId(0),
-                        "app",
                         "main",
                         new CallableId(1),
                         0,
@@ -50,7 +49,6 @@ class LowerToIRVMPipelineStageTest {
                         ReadOnlyList.from(new IRBackendExecutableFunction.Instruction(
                                 IRBackendExecutableFunction.InstructionKind.RET,
                                 "",
-                                "",
                                 null,
                                 null,
                                 Span.none())),
@@ -71,7 +69,6 @@ class LowerToIRVMPipelineStageTest {
         ctx.irBackend = IRBackend.builder()
                 .executableFunctions(ReadOnlyList.from(new IRBackendExecutableFunction(
                         new FileId(0),
-                        "app",
                         "main",
                         new CallableId(1),
                         0,
@@ -83,7 +80,6 @@ class LowerToIRVMPipelineStageTest {
                         ReadOnlyList.from(new IRBackendExecutableFunction.Instruction(
                                 IRBackendExecutableFunction.InstructionKind.RET,
                                 "",
-                                "",
                                 null,
                                 null,
                                 Span.none())),
@@ -104,7 +100,6 @@ class LowerToIRVMPipelineStageTest {
         ctx.irBackend = IRBackend.builder()
                 .executableFunctions(ReadOnlyList.from(new IRBackendExecutableFunction(
                         new FileId(9),
-                        "app",
                         "main",
                         new CallableId(1),
                         10,
@@ -116,7 +111,7 @@ class LowerToIRVMPipelineStageTest {
                         ReadOnlyList.from(
                                 new IRBackendExecutableFunction.Instruction(
                                         IRBackendExecutableFunction.InstructionKind.CALL_FUNC,
-                                        "app",
+                                        p.studio.compiler.source.identifiers.ModuleId.none(),
                                         "missing",
                                         new CallableId(99),
                                         null,
@@ -125,7 +120,6 @@ class LowerToIRVMPipelineStageTest {
                                 new IRBackendExecutableFunction.Instruction(
                                         IRBackendExecutableFunction.InstructionKind.RET,
                                         "",
-                                        "",
                                         null,
                                         null,
                                         Span.none())),
@@ -149,7 +143,6 @@ class LowerToIRVMPipelineStageTest {
                 .executableFunctions(ReadOnlyList.from(
                         new IRBackendExecutableFunction(
                                 new FileId(0),
-                                "app",
                                 "callee",
                                 new CallableId(2),
                                 0,
@@ -161,14 +154,12 @@ class LowerToIRVMPipelineStageTest {
                                 ReadOnlyList.from(new IRBackendExecutableFunction.Instruction(
                                         IRBackendExecutableFunction.InstructionKind.RET,
                                         "",
-                                        "",
                                         null,
                                         null,
                                         Span.none())),
                                 Span.none()),
                         new IRBackendExecutableFunction(
                                 new FileId(0),
-                                "app",
                                 "main",
                                 new CallableId(1),
                                 0,
@@ -180,7 +171,7 @@ class LowerToIRVMPipelineStageTest {
                                 ReadOnlyList.from(
                                         new IRBackendExecutableFunction.Instruction(
                                                 IRBackendExecutableFunction.InstructionKind.CALL_FUNC,
-                                                "app",
+                                                p.studio.compiler.source.identifiers.ModuleId.none(),
                                                 "callee",
                                                 new CallableId(2),
                                                 null,
@@ -191,7 +182,6 @@ class LowerToIRVMPipelineStageTest {
                                         new IRBackendExecutableFunction.Instruction(
                                                 IRBackendExecutableFunction.InstructionKind.RET,
                                                 "",
-                                                "",
                                                 null,
                                                 null,
                                                 Span.none())),
diff --git a/prometeu-compiler/prometeu-compiler-core/src/main/java/p/studio/compiler/source/tables/CallableSignatureRef.java b/prometeu-compiler/prometeu-compiler-core/src/main/java/p/studio/compiler/source/tables/CallableSignatureRef.java
index 5afcd8f4..dfc571ae 100644
--- a/prometeu-compiler/prometeu-compiler-core/src/main/java/p/studio/compiler/source/tables/CallableSignatureRef.java
+++ b/prometeu-compiler/prometeu-compiler-core/src/main/java/p/studio/compiler/source/tables/CallableSignatureRef.java
@@ -6,17 +6,15 @@ import java.util.Objects;
 
 public record CallableSignatureRef(
         ModuleId moduleId,
-        String moduleKey,
         String callableName,
         int arity,
         String typeShape) {
 
     public CallableSignatureRef(
-            final String moduleKey,
             final String callableName,
             final int arity,
             final String typeShape) {
-        this(ModuleId.none(), moduleKey, callableName, arity, typeShape);
+        this(ModuleId.none(), callableName, arity, typeShape);
     }
 
     public CallableSignatureRef {
@@ -24,7 +22,6 @@ public record CallableSignatureRef(
         if (!moduleId.isNone()) {
             moduleId.getIndex();
         }
-        moduleKey = moduleKey == null ? "" : moduleKey;
         callableName = Objects.requireNonNull(callableName, "callableName");
         typeShape = typeShape == null ? "" : typeShape;
         if (callableName.isBlank()) {
diff --git a/prometeu-compiler/prometeu-compiler-core/src/main/java/p/studio/compiler/source/tables/CallableTable.java b/prometeu-compiler/prometeu-compiler-core/src/main/java/p/studio/compiler/source/tables/CallableTable.java
index ce8d8a52..2ad5c275 100644
--- a/prometeu-compiler/prometeu-compiler-core/src/main/java/p/studio/compiler/source/tables/CallableTable.java
+++ b/prometeu-compiler/prometeu-compiler-core/src/main/java/p/studio/compiler/source/tables/CallableTable.java
@@ -10,19 +10,17 @@ public class CallableTable extends InternTable<CallableId, CallableSignatureRef>
     }
 
     public CallableId register(
-            final String moduleKey,
             final String callableName,
             final int arity,
             final String typeShape) {
-        return register(new CallableSignatureRef(ModuleId.none(), moduleKey, callableName, arity, typeShape));
+        return register(new CallableSignatureRef(ModuleId.none(), callableName, arity, typeShape));
     }
 
     public CallableId register(
             final ModuleId moduleId,
-            final String moduleKey,
             final String callableName,
             final int arity,
             final String typeShape) {
-        return register(new CallableSignatureRef(moduleId, moduleKey, callableName, arity, typeShape));
+        return register(new CallableSignatureRef(moduleId, callableName, arity, typeShape));
     }
 }
diff --git a/prometeu-compiler/prometeu-compiler-core/src/test/java/p/studio/compiler/source/tables/CallableTableTest.java b/prometeu-compiler/prometeu-compiler-core/src/test/java/p/studio/compiler/source/tables/CallableTableTest.java
index 6d2e56f7..c9a6db1e 100644
--- a/prometeu-compiler/prometeu-compiler-core/src/test/java/p/studio/compiler/source/tables/CallableTableTest.java
+++ b/prometeu-compiler/prometeu-compiler-core/src/test/java/p/studio/compiler/source/tables/CallableTableTest.java
@@ -11,9 +11,9 @@ class CallableTableTest {
     void shouldInternEqualCallableSignaturesToSameIdentifier() {
         final var table = new CallableTable();
 
-        final var first = table.register("app/main", "draw", 2, "(simple:int,simple:int)->unit");
-        final var second = table.register("app/main", "draw", 2, "(simple:int,simple:int)->unit");
-        final var third = table.register("app/main", "draw", 1, "(simple:int)->unit");
+        final var first = table.register("draw", 2, "(simple:int,simple:int)->unit");
+        final var second = table.register("draw", 2, "(simple:int,simple:int)->unit");
+        final var third = table.register("draw", 1, "(simple:int)->unit");
 
         assertEquals(first, second);
         assertEquals(2, table.size());
@@ -22,7 +22,7 @@ class CallableTableTest {
 
     @Test
     void shouldRejectInvalidCallableSignatureReferenceContract() {
-        assertThrows(IllegalArgumentException.class, () -> new CallableSignatureRef("app/main", "", 1, "(unit)->unit"));
-        assertThrows(IllegalArgumentException.class, () -> new CallableSignatureRef("app/main", "draw", -1, "(unit)->unit"));
+        assertThrows(IllegalArgumentException.class, () -> new CallableSignatureRef("", 1, "(unit)->unit"));
+        assertThrows(IllegalArgumentException.class, () -> new CallableSignatureRef("draw", -1, "(unit)->unit"));
     }
 }
diff --git a/prometeu-compiler/prometeu-frontend-api/src/main/java/p/studio/compiler/models/IRBackend.java b/prometeu-compiler/prometeu-frontend-api/src/main/java/p/studio/compiler/models/IRBackend.java
index e06f531c..33438418 100644
--- a/prometeu-compiler/prometeu-frontend-api/src/main/java/p/studio/compiler/models/IRBackend.java
+++ b/prometeu-compiler/prometeu-frontend-api/src/main/java/p/studio/compiler/models/IRBackend.java
@@ -15,7 +15,6 @@ import p.studio.utilities.structures.ReadOnlyList;
 
 import java.util.ArrayList;
 import java.util.LinkedHashSet;
-import java.util.List;
 
 @Builder
 @Getter
@@ -108,12 +107,10 @@ public class IRBackend {
                 final var signature = localCallableSignatures.get(i);
                 final var remappedModuleId = remapModuleId(
                         signature.moduleId(),
-                        signature.moduleKey(),
                         moduleRemap,
                         "callable signature");
                 remap[i] = callableTable.register(
                         remappedModuleId,
-                        signature.moduleKey(),
                         signature.callableName(),
                         signature.arity(),
                         signature.typeShape());
@@ -129,7 +126,6 @@ public class IRBackend {
             final var remappedInstructions = new ArrayList<IRBackendExecutableFunction.Instruction>(function.instructions().size());
             final var remappedFunctionModuleId = remapModuleId(
                     function.moduleId(),
-                    function.moduleKey(),
                     moduleRemap,
                     "function");
             for (final var instruction : function.instructions()) {
@@ -151,13 +147,11 @@ public class IRBackend {
                 }
                 final var remappedCalleeModuleId = remapModuleId(
                         instruction.calleeModuleId(),
-                        instruction.calleeModuleKey(),
                         moduleRemap,
                         "callee");
                 remappedInstructions.add(new IRBackendExecutableFunction.Instruction(
                         instruction.kind(),
                         remappedCalleeModuleId,
-                        instruction.calleeModuleKey(),
                         instruction.calleeCallableName(),
                         remappedCallee,
                         instruction.hostCall(),
@@ -171,7 +165,6 @@ public class IRBackend {
             return new IRBackendExecutableFunction(
                     function.fileId(),
                     remappedFunctionModuleId,
-                    function.moduleKey(),
                     function.callableName(),
                     remapCallableId(function.callableId(), callableRemap, "function"),
                     function.sourceStart(),
@@ -186,7 +179,6 @@ public class IRBackend {
 
         private ModuleId remapModuleId(
                 final ModuleId localModuleId,
-                final String moduleKey,
                 final ModuleId[] moduleRemap,
                 final String label) {
             if (localModuleId != null && !localModuleId.isNone()) {
@@ -196,33 +188,9 @@ public class IRBackend {
                 }
                 return moduleRemap[localIndex];
             }
-            final var fallbackReference = moduleReferenceFromKey(moduleKey);
-            if (fallbackReference != null) {
-                return moduleTable.register(fallbackReference);
-            }
             return ModuleId.none();
         }
 
-        private ModuleReference moduleReferenceFromKey(final String moduleKey) {
-            if (moduleKey == null || moduleKey.isBlank()) {
-                return null;
-            }
-            final var separator = moduleKey.indexOf(':');
-            if (separator <= 0) {
-                return null;
-            }
-            final var project = moduleKey.substring(0, separator).trim();
-            final var rawPath = moduleKey.substring(separator + 1).trim();
-            if (project.isBlank()) {
-                return null;
-            }
-            if (rawPath.isBlank()) {
-                return new ModuleReference(project, ReadOnlyList.empty());
-            }
-            final var segments = List.of(rawPath.split("/"));
-            return new ModuleReference(project, ReadOnlyList.wrap(segments));
-        }
-
         private CallableId remapCallableId(
                 final CallableId localCallableId,
                 final CallableId[] callableRemap,
diff --git a/prometeu-compiler/prometeu-frontend-api/src/main/java/p/studio/compiler/models/IRBackendExecutableFunction.java b/prometeu-compiler/prometeu-frontend-api/src/main/java/p/studio/compiler/models/IRBackendExecutableFunction.java
index 30a9cc96..c05867f6 100644
--- a/prometeu-compiler/prometeu-frontend-api/src/main/java/p/studio/compiler/models/IRBackendExecutableFunction.java
+++ b/prometeu-compiler/prometeu-frontend-api/src/main/java/p/studio/compiler/models/IRBackendExecutableFunction.java
@@ -12,7 +12,6 @@ import java.util.Objects;
 public record IRBackendExecutableFunction(
         FileId fileId,
         ModuleId moduleId,
-        String moduleKey,
         String callableName,
         CallableId callableId,
         int sourceStart,
@@ -26,7 +25,6 @@ public record IRBackendExecutableFunction(
 
     public IRBackendExecutableFunction(
             final FileId fileId,
-            final String moduleKey,
             final String callableName,
             final CallableId callableId,
             final int sourceStart,
@@ -40,7 +38,6 @@ public record IRBackendExecutableFunction(
         this(
                 fileId,
                 ModuleId.none(),
-                moduleKey,
                 callableName,
                 callableId,
                 sourceStart,
@@ -59,7 +56,6 @@ public record IRBackendExecutableFunction(
         if (!moduleId.isNone()) {
             moduleId.getIndex();
         }
-        moduleKey = moduleKey == null ? "" : moduleKey;
         callableName = Objects.requireNonNull(callableName, "callableName");
         if (callableName.isBlank()) {
             throw new IllegalArgumentException("callableName must not be blank");
@@ -88,7 +84,6 @@ public record IRBackendExecutableFunction(
     public record Instruction(
             InstructionKind kind,
             ModuleId calleeModuleId,
-            String calleeModuleKey,
             String calleeCallableName,
             CallableId calleeCallableId,
             HostCallMetadata hostCall,
@@ -101,19 +96,17 @@ public record IRBackendExecutableFunction(
         public Instruction(
                 final InstructionKind kind,
                 final ModuleId calleeModuleId,
-                final String calleeModuleKey,
                 final String calleeCallableName,
                 final CallableId calleeCallableId,
                 final HostCallMetadata hostCall,
                 final IntrinsicCallMetadata intrinsicCall,
                 final Span span) {
-            this(kind, calleeModuleId, calleeModuleKey, calleeCallableName, calleeCallableId, hostCall, intrinsicCall, null, null, null, null, span);
+            this(kind, calleeModuleId, calleeCallableName, calleeCallableId, hostCall, intrinsicCall, null, null, null, null, span);
         }
 
         public Instruction(
                 final InstructionKind kind,
                 final ModuleId calleeModuleId,
-                final String calleeModuleKey,
                 final String calleeCallableName,
                 final CallableId calleeCallableId,
                 final HostCallMetadata hostCall,
@@ -121,36 +114,33 @@ public record IRBackendExecutableFunction(
                 final Integer expectedArgSlots,
                 final Integer expectedRetSlots,
                 final Span span) {
-            this(kind, calleeModuleId, calleeModuleKey, calleeCallableName, calleeCallableId, hostCall, intrinsicCall, null, null, expectedArgSlots, expectedRetSlots, span);
+            this(kind, calleeModuleId, calleeCallableName, calleeCallableId, hostCall, intrinsicCall, null, null, expectedArgSlots, expectedRetSlots, span);
         }
 
         public Instruction(
                 final InstructionKind kind,
                 final ModuleId calleeModuleId,
-                final String calleeModuleKey,
                 final String calleeCallableName,
                 final HostCallMetadata hostCall,
                 final IntrinsicCallMetadata intrinsicCall,
                 final Span span) {
-            this(kind, calleeModuleId, calleeModuleKey, calleeCallableName, null, hostCall, intrinsicCall, null, null, null, null, span);
+            this(kind, calleeModuleId, calleeCallableName, null, hostCall, intrinsicCall, null, null, null, null, span);
         }
 
         public Instruction(
                 final InstructionKind kind,
                 final ModuleId calleeModuleId,
-                final String calleeModuleKey,
                 final String calleeCallableName,
                 final HostCallMetadata hostCall,
                 final IntrinsicCallMetadata intrinsicCall,
                 final Integer expectedArgSlots,
                 final Integer expectedRetSlots,
                 final Span span) {
-            this(kind, calleeModuleId, calleeModuleKey, calleeCallableName, null, hostCall, intrinsicCall, null, null, expectedArgSlots, expectedRetSlots, span);
+            this(kind, calleeModuleId, calleeCallableName, null, hostCall, intrinsicCall, null, null, expectedArgSlots, expectedRetSlots, span);
         }
 
         public Instruction(
                 final InstructionKind kind,
-                final String calleeModuleKey,
                 final String calleeCallableName,
                 final CallableId calleeCallableId,
                 final HostCallMetadata hostCall,
@@ -160,23 +150,21 @@ public record IRBackendExecutableFunction(
                 final Integer expectedArgSlots,
                 final Integer expectedRetSlots,
                 final Span span) {
-            this(kind, ModuleId.none(), calleeModuleKey, calleeCallableName, calleeCallableId, hostCall, intrinsicCall, label, targetLabel, expectedArgSlots, expectedRetSlots, span);
+            this(kind, ModuleId.none(), calleeCallableName, calleeCallableId, hostCall, intrinsicCall, label, targetLabel, expectedArgSlots, expectedRetSlots, span);
         }
 
         public Instruction(
                 final InstructionKind kind,
-                final String calleeModuleKey,
                 final String calleeCallableName,
                 final CallableId calleeCallableId,
                 final HostCallMetadata hostCall,
                 final IntrinsicCallMetadata intrinsicCall,
                 final Span span) {
-            this(kind, ModuleId.none(), calleeModuleKey, calleeCallableName, calleeCallableId, hostCall, intrinsicCall, null, null, null, null, span);
+            this(kind, ModuleId.none(), calleeCallableName, calleeCallableId, hostCall, intrinsicCall, null, null, null, null, span);
         }
 
         public Instruction(
                 final InstructionKind kind,
-                final String calleeModuleKey,
                 final String calleeCallableName,
                 final CallableId calleeCallableId,
                 final HostCallMetadata hostCall,
@@ -184,29 +172,27 @@ public record IRBackendExecutableFunction(
                 final Integer expectedArgSlots,
                 final Integer expectedRetSlots,
                 final Span span) {
-            this(kind, ModuleId.none(), calleeModuleKey, calleeCallableName, calleeCallableId, hostCall, intrinsicCall, null, null, expectedArgSlots, expectedRetSlots, span);
+            this(kind, ModuleId.none(), calleeCallableName, calleeCallableId, hostCall, intrinsicCall, null, null, expectedArgSlots, expectedRetSlots, span);
         }
 
         public Instruction(
                 final InstructionKind kind,
-                final String calleeModuleKey,
                 final String calleeCallableName,
                 final HostCallMetadata hostCall,
                 final IntrinsicCallMetadata intrinsicCall,
                 final Span span) {
-            this(kind, ModuleId.none(), calleeModuleKey, calleeCallableName, null, hostCall, intrinsicCall, null, null, null, null, span);
+            this(kind, ModuleId.none(), calleeCallableName, null, hostCall, intrinsicCall, null, null, null, null, span);
         }
 
         public Instruction(
                 final InstructionKind kind,
-                final String calleeModuleKey,
                 final String calleeCallableName,
                 final HostCallMetadata hostCall,
                 final IntrinsicCallMetadata intrinsicCall,
                 final Integer expectedArgSlots,
                 final Integer expectedRetSlots,
                 final Span span) {
-            this(kind, ModuleId.none(), calleeModuleKey, calleeCallableName, null, hostCall, intrinsicCall, null, null, expectedArgSlots, expectedRetSlots, span);
+            this(kind, ModuleId.none(), calleeCallableName, null, hostCall, intrinsicCall, null, null, expectedArgSlots, expectedRetSlots, span);
         }
 
         public Instruction {
@@ -216,7 +202,6 @@ public record IRBackendExecutableFunction(
             if (!calleeModuleId.isNone()) {
                 calleeModuleId.getIndex();
             }
-            calleeModuleKey = calleeModuleKey == null ? "" : calleeModuleKey;
             calleeCallableName = calleeCallableName == null ? "" : calleeCallableName;
             label = label == null ? "" : label;
             targetLabel = targetLabel == null ? "" : targetLabel;
diff --git a/prometeu-compiler/prometeu-frontend-api/src/test/java/p/studio/compiler/models/IRBackendExecutableContractTest.java b/prometeu-compiler/prometeu-frontend-api/src/test/java/p/studio/compiler/models/IRBackendExecutableContractTest.java
index 3dc29355..baa64a0c 100644
--- a/prometeu-compiler/prometeu-frontend-api/src/test/java/p/studio/compiler/models/IRBackendExecutableContractTest.java
+++ b/prometeu-compiler/prometeu-frontend-api/src/test/java/p/studio/compiler/models/IRBackendExecutableContractTest.java
@@ -21,7 +21,7 @@ class IRBackendExecutableContractTest {
     void callInstructionMustRequireCategorySpecificMetadata() {
         assertThrows(IllegalArgumentException.class, () -> new IRBackendExecutableFunction.Instruction(
                 IRBackendExecutableFunction.InstructionKind.CALL_HOST,
-                "",
+                ModuleId.none(),
                 "",
                 null,
                 null,
@@ -29,7 +29,7 @@ class IRBackendExecutableContractTest {
 
         final var callFunc = new IRBackendExecutableFunction.Instruction(
                 IRBackendExecutableFunction.InstructionKind.CALL_FUNC,
-                "app/main",
+                ModuleId.none(),
                 "foo",
                 new CallableId(7),
                 null,
@@ -42,7 +42,6 @@ class IRBackendExecutableContractTest {
     void functionContractMustRejectInvalidSlotAndSpanBounds() {
         assertThrows(IllegalArgumentException.class, () -> new IRBackendExecutableFunction(
                 new FileId(1),
-                "app",
                 "main",
                 new CallableId(1),
                 10,
@@ -56,7 +55,6 @@ class IRBackendExecutableContractTest {
 
         final var thrown = assertThrows(IllegalArgumentException.class, () -> new IRBackendExecutableFunction(
                 new FileId(1),
-                "app",
                 "main",
                 new CallableId(1),
                 0,
@@ -74,7 +72,7 @@ class IRBackendExecutableContractTest {
     void instructionContractMustRejectMixedMetadataKinds() {
         assertThrows(IllegalArgumentException.class, () -> new IRBackendExecutableFunction.Instruction(
                 IRBackendExecutableFunction.InstructionKind.CALL_FUNC,
-                "app/main",
+                ModuleId.none(),
                 "foo",
                 new CallableId(1),
                 new IRBackendExecutableFunction.HostCallMetadata("gfx", "draw", 1, 0, 0),
@@ -93,7 +91,7 @@ class IRBackendExecutableContractTest {
     void jumpAndLabelContractMustRequireNames() {
         assertThrows(IllegalArgumentException.class, () -> new IRBackendExecutableFunction.Instruction(
                 IRBackendExecutableFunction.InstructionKind.LABEL,
-                "",
+                ModuleId.none(),
                 "",
                 null,
                 null,
@@ -106,7 +104,7 @@ class IRBackendExecutableContractTest {
 
         assertThrows(IllegalArgumentException.class, () -> new IRBackendExecutableFunction.Instruction(
                 IRBackendExecutableFunction.InstructionKind.JMP,
-                "",
+                ModuleId.none(),
                 "",
                 null,
                 null,
@@ -125,7 +123,6 @@ class IRBackendExecutableContractTest {
                 ReadOnlyList.empty(),
                 ReadOnlyList.from(new IRBackendExecutableFunction(
                         new FileId(1),
-                        "app/main",
                         "entry",
                         new CallableId(0),
                         0,
@@ -137,21 +134,18 @@ class IRBackendExecutableContractTest {
                         ReadOnlyList.from(new IRBackendExecutableFunction.Instruction(
                                 IRBackendExecutableFunction.InstructionKind.HALT,
                                 "",
-                                "",
-                                null,
                                 null,
                                 null,
                                 Span.none())),
                         Span.none())),
                 IRReservedMetadata.empty(),
-                ReadOnlyList.from(new CallableSignatureRef("app/main", "entry", 0, "() -> unit")),
+                ReadOnlyList.from(new CallableSignatureRef("entry", 0, "() -> unit")),
                 ReadOnlyList.empty());
         final var fileB = new IRBackendFile(
                 new FileId(2),
                 ReadOnlyList.empty(),
                 ReadOnlyList.from(new IRBackendExecutableFunction(
                         new FileId(2),
-                        "app/main",
                         "aux",
                         new CallableId(0),
                         11,
@@ -163,14 +157,12 @@ class IRBackendExecutableContractTest {
                         ReadOnlyList.from(new IRBackendExecutableFunction.Instruction(
                                 IRBackendExecutableFunction.InstructionKind.RET,
                                 "",
-                                "",
-                                null,
                                 null,
                                 null,
                                 Span.none())),
                         Span.none())),
                 IRReservedMetadata.empty(),
-                ReadOnlyList.from(new CallableSignatureRef("app/main", "aux", 0, "() -> unit")),
+                ReadOnlyList.from(new CallableSignatureRef("aux", 0, "() -> unit")),
                 ReadOnlyList.empty());
 
         final var aggregator = IRBackend.aggregator();
@@ -213,7 +205,6 @@ class IRBackendExecutableContractTest {
                 ReadOnlyList.empty(),
                 ReadOnlyList.from(new IRBackendExecutableFunction(
                         new FileId(1),
-                        "app/main",
                         "entry",
                         new CallableId(0),
                         0,
@@ -225,20 +216,18 @@ class IRBackendExecutableContractTest {
                         ReadOnlyList.from(new IRBackendExecutableFunction.Instruction(
                                 IRBackendExecutableFunction.InstructionKind.CALL_INTRINSIC,
                                 "",
-                                "",
                                 null,
                                 new IRBackendExecutableFunction.IntrinsicCallMetadata("core.color.pack", 1, new IntrinsicId(0)),
                                 Span.none())),
                         Span.none())),
                 IRReservedMetadata.empty(),
-                ReadOnlyList.from(new CallableSignatureRef("app/main", "entry", 0, "() -> unit")),
+                ReadOnlyList.from(new CallableSignatureRef("entry", 0, "() -> unit")),
                 ReadOnlyList.from(new IntrinsicReference("core.color.pack", 1)));
         final var fileB = new IRBackendFile(
                 new FileId(2),
                 ReadOnlyList.empty(),
                 ReadOnlyList.from(new IRBackendExecutableFunction(
                         new FileId(2),
-                        "app/main",
                         "aux",
                         new CallableId(0),
                         11,
@@ -250,13 +239,12 @@ class IRBackendExecutableContractTest {
                         ReadOnlyList.from(new IRBackendExecutableFunction.Instruction(
                                 IRBackendExecutableFunction.InstructionKind.CALL_INTRINSIC,
                                 "",
-                                "",
                                 null,
                                 new IRBackendExecutableFunction.IntrinsicCallMetadata("core.color.pack", 1, new IntrinsicId(0)),
                                 Span.none())),
                         Span.none())),
                 IRReservedMetadata.empty(),
-                ReadOnlyList.from(new CallableSignatureRef("app/main", "aux", 0, "() -> unit")),
+                ReadOnlyList.from(new CallableSignatureRef("aux", 0, "() -> unit")),
                 ReadOnlyList.from(new IntrinsicReference("core.color.pack", 1)));
 
         final var aggregator = IRBackend.aggregator();
@@ -280,7 +268,6 @@ class IRBackendExecutableContractTest {
                 ReadOnlyList.empty(),
                 ReadOnlyList.from(new IRBackendExecutableFunction(
                         new FileId(7),
-                        "app/main",
                         "main",
                         new CallableId(0),
                         10,
@@ -292,13 +279,12 @@ class IRBackendExecutableContractTest {
                         ReadOnlyList.from(new IRBackendExecutableFunction.Instruction(
                                 IRBackendExecutableFunction.InstructionKind.RET,
                                 "",
-                                "",
                                 null,
                                 null,
                                 instructionSpan)),
                         functionSpan)),
                 IRReservedMetadata.empty(),
-                ReadOnlyList.from(new CallableSignatureRef("app/main", "main", 0, "() -> unit")),
+                ReadOnlyList.from(new CallableSignatureRef("main", 0, "() -> unit")),
                 ReadOnlyList.empty());
 
         final var aggregator = IRBackend.aggregator();
@@ -323,7 +309,6 @@ class IRBackendExecutableContractTest {
                 ReadOnlyList.from(new IRBackendExecutableFunction(
                         new FileId(1),
                         new ModuleId(0),
-                        "app:mod/a",
                         "entry",
                         new CallableId(0),
                         0,
@@ -335,14 +320,13 @@ class IRBackendExecutableContractTest {
                         ReadOnlyList.from(new IRBackendExecutableFunction.Instruction(
                                 IRBackendExecutableFunction.InstructionKind.RET,
                                 "",
-                                "",
                                 null,
                                 null,
                                 Span.none())),
                         Span.none())),
                 IRReservedMetadata.empty(),
                 ReadOnlyList.from(new ModuleReference("app", ReadOnlyList.from("mod", "a"))),
-                ReadOnlyList.from(new CallableSignatureRef(new ModuleId(0), "app:mod/a", "entry", 0, "() -> unit")),
+                ReadOnlyList.from(new CallableSignatureRef(new ModuleId(0), "entry", 0, "() -> unit")),
                 ReadOnlyList.empty());
         final var fileB = new IRBackendFile(
                 new FileId(2),
@@ -350,7 +334,6 @@ class IRBackendExecutableContractTest {
                 ReadOnlyList.from(new IRBackendExecutableFunction(
                         new FileId(2),
                         new ModuleId(0),
-                        "app:mod/b",
                         "aux",
                         new CallableId(0),
                         6,
@@ -362,14 +345,13 @@ class IRBackendExecutableContractTest {
                         ReadOnlyList.from(new IRBackendExecutableFunction.Instruction(
                                 IRBackendExecutableFunction.InstructionKind.RET,
                                 "",
-                                "",
                                 null,
                                 null,
                                 Span.none())),
                         Span.none())),
                 IRReservedMetadata.empty(),
                 ReadOnlyList.from(new ModuleReference("app", ReadOnlyList.from("mod", "b"))),
-                ReadOnlyList.from(new CallableSignatureRef(new ModuleId(0), "app:mod/b", "aux", 0, "() -> unit")),
+                ReadOnlyList.from(new CallableSignatureRef(new ModuleId(0), "aux", 0, "() -> unit")),
                 ReadOnlyList.empty());
 
         final var aggregator = IRBackend.aggregator();