fix(es/minifier): Preserve return values of recursive IIFE (#6142)

**Description:**

This PR fixes the logic for dropping return values of IIFE.

**Related issue:**

 - Closes https://github.com/swc-project/swc/issues/6141.

crates/swc/tests/tsc-references/witness.2.minified.js

@@ -3,6 +3,8 @@ import _class_call_check from "@swc/helpers/src/_class_call_check.mjs";
 var co2, cnd1, or1, or2, or3, and1, and3, propAcc1, M2, varInit = varInit;
 !function fnReturn1() {
     return fnReturn1();
+}(), function fnReturn2() {
+    return fnReturn2;
 }();
 var co2 = co2, cnd1 = cnd1 ? 0 : 1, or1 = or1 || "", or2 = or2, or3 = or3 || or3, and1 = and1 && "", and3 = and3 && and3;
 !function fnCall() {

crates/swc_ecma_minifier/src/compress/pure/misc.rs

@@ -4,7 +4,7 @@ use swc_atoms::js_word;
 use swc_common::{iter::IdentifyLast, util::take::Take, Span, DUMMY_SP};
 use swc_ecma_ast::*;
 use swc_ecma_utils::{
-    ExprExt, ExprFactory, Type,
+    ExprExt, ExprFactory, IdentUsageFinder, Type,
     Value::{self, Known},
 };
 
@@ -1060,6 +1060,12 @@ impl Pure<'_> {
                 match &mut **callee {
                     Expr::Fn(callee) => {
                         if let Some(body) = &mut callee.function.body {
+                            if let Some(ident) = &callee.ident {
+                                if IdentUsageFinder::find(&ident.to_id(), body) {
+                                    return;
+                                }
+                            }
+
                             for stmt in &mut body.stmts {
                                 self.ignore_return_value_of_return_stmt(stmt, opts);
                             }

crates/swc_ecma_minifier/tests/benches-full/echarts.js

@@ -13268,6 +13268,7 @@
                         var textGuideLineConfig = el.textGuideLineConfig;
                         labelLine.z = z, labelLine.zlevel = zlevel, isFinite(maxZ2) && (labelLine.z2 = maxZ2 + (textGuideLineConfig && textGuideLineConfig.showAbove ? 1 : -1));
                     }
+                    return maxZ2;
                 }(view.group, model.get('z') || 0, model.get('zlevel') || 0, -1 / 0);
             }
             function clearStates(model, view) {

crates/swc_ecma_minifier/tests/benches-full/react.js

@@ -291,7 +291,7 @@
                         return c;
                     });
                 } else null != mappedChild && (isValidElement(mappedChild) && (oldElement = mappedChild, newKey = escapedPrefix + (mappedChild.key && (!_child || _child.key !== mappedChild.key) ? escapeUserProvidedKey('' + mappedChild.key) + '/' : '') + childKey, mappedChild = ReactElement(oldElement.type, newKey, oldElement.ref, oldElement._self, oldElement._source, oldElement._owner, oldElement.props)), array.push(mappedChild));
-                return;
+                return 1;
             }
             var subtreeCount = 0, nextNamePrefix = '' === nameSoFar ? '.' : nameSoFar + ':';
             if (Array.isArray(children)) for(var i = 0; i < children.length; i++)nextName = nextNamePrefix + getElementKey(child = children[i], i), subtreeCount += mapIntoArray(child, array, escapedPrefix, nextName, callback);
@@ -306,6 +306,7 @@
                     throw Error("Objects are not valid as a React child (found: " + ('[object Object]' === childrenString ? 'object with keys {' + Object.keys(children).join(', ') + '}' : childrenString) + "). If you meant to render a collection of children, use an array instead.");
                 }
             }
+            return subtreeCount;
         }(children, result, '', '', function(child) {
             return func.call(context, child, count++);
         }), result;

crates/swc_ecma_minifier/tests/fixture/issues/2257/full/output.js

@@ -16507,7 +16507,7 @@
                         ref: a1.ref,
                         props: a1.props,
                         _owner: a1._owner
-                    }), b.push(d));
+                    }), b.push(d)), 1;
                     if (h = 0, e = "" === e ? "." : e + ":", Array.isArray(a)) for(var g = 0; g < a.length; g++){
                         k = a[g];
                         var f = e + N(k, g);
@@ -16515,6 +16515,7 @@
                     }
                     else if ("function" == typeof (f = null === (a2 = a) || "object" != typeof a2 ? null : "function" == typeof (a2 = x && a2[x] || a2["@@iterator"]) ? a2 : null)) for(a = f.call(a), g = 0; !(k = a.next()).done;)f = e + N(k = k.value, g++), h += O(k, b, c, f, d);
                     else if ("object" === k) throw Error(z(31, "[object Object]" == (b = "" + a) ? "object with keys {" + Object.keys(a).join(", ") + "}" : b));
+                    return h;
                 }(a, e, "", "", function(a) {
                     return b.call(c, a, d++);
                 }), e;

crates/swc_ecma_minifier/tests/fixture/issues/6141/input.js

@@ -0,0 +1,14 @@
+(function foo(obj) {
+    if (obj) {
+        for (const key in obj) {
+            const element = obj[key];
+
+            if (element && foo(element.children)) {
+                // do something
+            }
+        }
+
+        return true;
+    }
+    return false;
+})()

crates/swc_ecma_minifier/tests/fixture/issues/6141/output.js

@@ -0,0 +1,10 @@
+!function foo(obj) {
+    if (obj) {
+        for(const key in obj){
+            const element = obj[key];
+            element && foo(element.children);
+        }
+        return !0;
+    }
+    return !1;
+}();

crates/swc_ecma_minifier/tests/fixture/next/regression-1/framework-798bab57daac3897/output.js

@@ -5946,7 +5946,7 @@
                         ref: a1.ref,
                         props: a1.props,
                         _owner: a1._owner
-                    }), b.push(c));
+                    }), b.push(c)), 1;
                     if (h = 0, d = "" === d ? "." : d + ":", I(a)) for(var g = 0; g < a.length; g++){
                         k = a[g];
                         var f = d + Q(k, g);
@@ -5954,6 +5954,7 @@
                     }
                     else if ("function" == typeof (f = null === (a2 = a) || "object" != typeof a2 ? null : "function" == typeof (a2 = z && a2[z] || a2["@@iterator"]) ? a2 : null)) for(a = f.call(a), g = 0; !(k = a.next()).done;)f = d + Q(k = k.value, g++), h += R(k, b, e, f, c);
                     else if ("object" === k) throw Error("Objects are not valid as a React child (found: " + ("[object Object]" === (b = String(a)) ? "object with keys {" + Object.keys(a).join(", ") + "}" : b) + "). If you meant to render a collection of children, use an array instead.");
+                    return h;
                 }(a, d, "", "", function(a) {
                     return b.call(e, a, c++);
                 }), d;

crates/swc_ecma_minifier/tests/projects/output/react-17.0.1.js

@@ -291,7 +291,7 @@
                         return c;
                     });
                 } else null != mappedChild && (isValidElement(mappedChild) && (oldElement = mappedChild, newKey = escapedPrefix + (mappedChild.key && (!_child || _child.key !== mappedChild.key) ? escapeUserProvidedKey("" + mappedChild.key) + "/" : "") + childKey, mappedChild = ReactElement(oldElement.type, newKey, oldElement.ref, oldElement._self, oldElement._source, oldElement._owner, oldElement.props)), array.push(mappedChild));
-                return;
+                return 1;
             }
             var subtreeCount = 0, nextNamePrefix = "" === nameSoFar ? "." : nameSoFar + ":";
             if (Array.isArray(children)) for(var i = 0; i < children.length; i++)nextName = nextNamePrefix + getElementKey(child = children[i], i), subtreeCount += mapIntoArray(child, array, escapedPrefix, nextName, callback);
@@ -306,6 +306,7 @@
                     throw Error("Objects are not valid as a React child (found: " + ("[object Object]" === childrenString ? "object with keys {" + Object.keys(children).join(", ") + "}" : childrenString) + "). If you meant to render a collection of children, use an array instead.");
                 }
             }
+            return subtreeCount;
         }(children, result, "", "", function(child) {
             return func.call(context, child, count++);
         }), result;