JS: fix removal of unused lambdas after inlining

Author: Alexey Andreev

js/js.inliner/src/org/jetbrains/kotlin/js/inline/clean/removeUnusedFunctionDefinitions.kt

@@ -37,9 +37,13 @@ fun removeUnusedFunctionDefinitions(root: JsNode, functions: Map<JsName, JsFunct
         removableFunctions
     }
 
-    NodeRemover(JsPropertyInitializer::class.java) {
-        val function = it.valueExpr as? JsFunction
-        function != null && function in removable
+    NodeRemover(JsStatement::class.java) { statement ->
+        val expression = when (statement) {
+            is JsExpressionStatement -> statement.expression
+            is JsVars -> if (statement.vars.size == 1) statement.vars[0].initExpression else null
+            else -> null
+        }
+        expression is JsFunction && expression in removable
     }.accept(root)
 }
 

js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/BoxJsTestGenerated.java

@@ -4562,6 +4562,12 @@ public void testAllFilesPresentInInlineSizeReduction() throws Exception {
             KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("js/js.translator/testData/box/inlineSizeReduction"), Pattern.compile("^([^_](.+))\\.kt$"), TargetBackend.ANY, true);
         }
 
+        @TestMetadata("inlineLambdaCleanup.kt")
+        public void testInlineLambdaCleanup() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("js/js.translator/testData/box/inlineSizeReduction/inlineLambdaCleanup.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("inlineOrder.kt")
         public void testInlineOrder() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("js/js.translator/testData/box/inlineSizeReduction/inlineOrder.kt");

js/js.tests/test/org/jetbrains/kotlin/js/test/utils/CallCounter.java

@@ -28,21 +28,35 @@ public class CallCounter extends RecursiveJsVisitor {
     @NotNull
     private final Set<String> exceptFunctionNames;
 
+    @NotNull
+    private final Set<String> exceptScopes;
+
+    private int excludedScopeOccurrenceCount;
+
     @NotNull
     public static CallCounter countCalls(@NotNull JsNode node) {
         return countCalls(node, Collections.<String>emptySet());
     }
 
     @NotNull
     public static CallCounter countCalls(@NotNull JsNode node, @NotNull Set<String> exceptFunctionNames) {
-        CallCounter visitor = new CallCounter(new HashSet<String>(exceptFunctionNames));
+        CallCounter visitor = new CallCounter(new HashSet<String>(exceptFunctionNames), Collections.<String>emptySet());
         node.accept(visitor);
 
         return visitor;
     }
 
-    private CallCounter(@NotNull Set<String> exceptFunctionNames) {
+    @NotNull
+    public static CallCounter countCallsWithExcludedScopes(@NotNull JsNode node, @NotNull Set<String> exceptScopes) {
+        CallCounter visitor = new CallCounter(Collections.<String>emptySet(), new HashSet<String>(exceptScopes));
+        node.accept(visitor);
+
+        return visitor;
+    }
+
+    private CallCounter(@NotNull Set<String> exceptFunctionNames, @NotNull Set<String> exceptScopes) {
         this.exceptFunctionNames = exceptFunctionNames;
+        this.exceptScopes = exceptScopes;
     }
 
     public int getTotalCallsCount() {
@@ -89,6 +103,28 @@ public void visitInvocation(@NotNull JsInvocation invocation) {
         }
     }
 
+    @Override
+    public void visitFunction(@NotNull JsFunction x) {
+        if (x.getName() != null && exceptScopes.contains(x.getName().getIdent())) {
+            excludedScopeOccurrenceCount++;
+            return;
+        }
+        super.visitFunction(x);
+    }
+
+    @Override
+    public void visitVars(@NotNull JsVars x) {
+        for (JsVars.JsVar jsVar : x.getVars()) {
+            if (jsVar.getInitExpression() == null) continue;
+            if (!exceptScopes.contains(jsVar.getName().getIdent())) {
+                accept(jsVar.getInitExpression());
+            }
+            else {
+                excludedScopeOccurrenceCount++;
+            }
+        }
+    }
+
     private static boolean matchesQualifiers(JsNameRef nameRef, List<String> expectedQualifierChain) {
         JsExpression currentQualifier = nameRef;
 
@@ -108,4 +144,8 @@ private static boolean matchesQualifiers(JsNameRef nameRef, List<String> expecte
 
         return true;
     }
+
+    public int getExcludedScopeOccurrenceCount() {
+        return excludedScopeOccurrenceCount;
+    }
 }

js/js.tests/test/org/jetbrains/kotlin/js/test/utils/DirectiveTestUtils.java

@@ -49,7 +49,7 @@ void processEntry(@NotNull JsNode ast, @NotNull ArgumentsHelper arguments) throw
     private static final DirectiveHandler FUNCTION_NOT_CALLED = new DirectiveHandler("CHECK_NOT_CALLED") {
         @Override
         void processEntry(@NotNull JsNode ast, @NotNull ArgumentsHelper arguments) throws Exception {
-            checkFunctionNotCalled(ast, arguments.getFirst());
+            checkFunctionNotCalled(ast, arguments.getFirst(), arguments.findNamedArgument("except"));
         }
     };
 
@@ -296,12 +296,16 @@ public static void checkPropertyNotUsed(JsNode node, String propertyName, boolea
     }
 
 
-    public static void checkFunctionNotCalled(JsNode node, String functionName) throws Exception {
-        CallCounter counter = CallCounter.countCalls(node);
+    public static void checkFunctionNotCalled(@NotNull JsNode node, @NotNull String functionName, @Nullable String exceptFunction)
+            throws Exception {
+        Set<String> excludedScopes = exceptFunction != null ? Collections.singleton(exceptFunction) : Collections.<String>emptySet();
+
+        CallCounter counter = CallCounter.countCallsWithExcludedScopes(node, excludedScopes);
         int functionCalledCount = counter.getQualifiedCallsCount(functionName);
 
         String errorMessage = "inline function `" + functionName + "` is called";
         assertEquals(errorMessage, 0, functionCalledCount);
+        assertEquals("Not all excluded scopes found", excludedScopes.size(), counter.getExcludedScopeOccurrenceCount());
     }
 
     public static void checkCalledInScope(

js/js.translator/testData/box/inlineSizeReduction/inlineLambdaCleanup.kt

@@ -0,0 +1,7 @@
+// CHECK_NOT_CALLED: produceOK except=box
+
+fun produceOK() = "OK"
+
+private inline fun <T> block(f: () -> T) = f()
+
+fun box(): String = block { produceOK() }