fix(es/minifier): Don't inline a function if we need referential equality (#4665)

crates/swc/tests/tsc-references/typeofOperatorWithBooleanType_es5.2.minified.js

@@ -19,7 +19,7 @@ var objA = new A();
 void 0 === BOOLEAN || swcHelpers.typeOf(BOOLEAN), swcHelpers.typeOf(!0), swcHelpers.typeOf({
     x: !0,
     y: !1
-}), swcHelpers.typeOf(objA.a), swcHelpers.typeOf(M.n), swcHelpers.typeOf(!0), swcHelpers.typeOf(A.foo()), swcHelpers.typeOf(void 0 === BOOLEAN ? "undefined" : swcHelpers.typeOf(BOOLEAN)), swcHelpers.typeOf(!0), void 0 === BOOLEAN || swcHelpers.typeOf(BOOLEAN), swcHelpers.typeOf(!0), swcHelpers.typeOf(!0), swcHelpers.typeOf(objA.a), swcHelpers.typeOf(M.n);
+}), swcHelpers.typeOf(objA.a), swcHelpers.typeOf(M.n), swcHelpers.typeOf(foo()), swcHelpers.typeOf(A.foo()), swcHelpers.typeOf(void 0 === BOOLEAN ? "undefined" : swcHelpers.typeOf(BOOLEAN)), swcHelpers.typeOf(!0), void 0 === BOOLEAN || swcHelpers.typeOf(BOOLEAN), swcHelpers.typeOf(foo()), swcHelpers.typeOf(!0), swcHelpers.typeOf(objA.a), swcHelpers.typeOf(M.n);
 z: void 0 === BOOLEAN || swcHelpers.typeOf(BOOLEAN);
 r: swcHelpers.typeOf(foo);
 z: swcHelpers.typeOf(!0);

crates/swc/tests/tsc-references/typeofOperatorWithNumberType_es5.2.minified.js

@@ -28,7 +28,7 @@ void 0 === NUMBER || swcHelpers.typeOf(NUMBER), swcHelpers.typeOf(NUMBER1), swcH
     y: function(n) {
         return n;
     }
-}), swcHelpers.typeOf(objA.a), swcHelpers.typeOf(M.n), swcHelpers.typeOf(NUMBER1[0]), swcHelpers.typeOf(1), swcHelpers.typeOf(A.foo()), swcHelpers.typeOf(NUMBER + NUMBER), swcHelpers.typeOf(void 0 === NUMBER ? "undefined" : swcHelpers.typeOf(NUMBER)), swcHelpers.typeOf(swcHelpers.typeOf(swcHelpers.typeOf(NUMBER + NUMBER))), swcHelpers.typeOf(1), void 0 === NUMBER || swcHelpers.typeOf(NUMBER), swcHelpers.typeOf(NUMBER1), swcHelpers.typeOf(1), swcHelpers.typeOf(objA.a), swcHelpers.typeOf(M.n), swcHelpers.typeOf(objA.a), M.n;
+}), swcHelpers.typeOf(objA.a), swcHelpers.typeOf(M.n), swcHelpers.typeOf(NUMBER1[0]), swcHelpers.typeOf(foo()), swcHelpers.typeOf(A.foo()), swcHelpers.typeOf(NUMBER + NUMBER), swcHelpers.typeOf(void 0 === NUMBER ? "undefined" : swcHelpers.typeOf(NUMBER)), swcHelpers.typeOf(swcHelpers.typeOf(swcHelpers.typeOf(NUMBER + NUMBER))), swcHelpers.typeOf(1), void 0 === NUMBER || swcHelpers.typeOf(NUMBER), swcHelpers.typeOf(NUMBER1), swcHelpers.typeOf(foo()), swcHelpers.typeOf(objA.a), swcHelpers.typeOf(M.n), swcHelpers.typeOf(objA.a), M.n;
 z: void 0 === NUMBER || swcHelpers.typeOf(NUMBER);
 x: swcHelpers.typeOf(NUMBER1);
 r: swcHelpers.typeOf(foo);

crates/swc/tests/tsc-references/typeofOperatorWithStringType_es5.2.minified.js

@@ -28,7 +28,7 @@ void 0 === STRING || swcHelpers.typeOf(STRING), swcHelpers.typeOf(STRING1), swcH
     y: function(s) {
         return s;
     }
-}), swcHelpers.typeOf(objA.a), swcHelpers.typeOf(M.n), swcHelpers.typeOf(STRING1[0]), swcHelpers.typeOf("abc"), swcHelpers.typeOf(A.foo()), swcHelpers.typeOf(STRING + STRING), swcHelpers.typeOf(STRING.charAt(0)), swcHelpers.typeOf(void 0 === STRING ? "undefined" : swcHelpers.typeOf(STRING)), swcHelpers.typeOf(swcHelpers.typeOf(swcHelpers.typeOf(STRING + STRING))), swcHelpers.typeOf(""), void 0 === STRING || swcHelpers.typeOf(STRING), swcHelpers.typeOf(STRING1), swcHelpers.typeOf("abc"), swcHelpers.typeOf(objA.a), M.n;
+}), swcHelpers.typeOf(objA.a), swcHelpers.typeOf(M.n), swcHelpers.typeOf(STRING1[0]), swcHelpers.typeOf(foo()), swcHelpers.typeOf(A.foo()), swcHelpers.typeOf(STRING + STRING), swcHelpers.typeOf(STRING.charAt(0)), swcHelpers.typeOf(void 0 === STRING ? "undefined" : swcHelpers.typeOf(STRING)), swcHelpers.typeOf(swcHelpers.typeOf(swcHelpers.typeOf(STRING + STRING))), swcHelpers.typeOf(""), void 0 === STRING || swcHelpers.typeOf(STRING), swcHelpers.typeOf(STRING1), swcHelpers.typeOf(foo()), swcHelpers.typeOf(objA.a), M.n;
 z: void 0 === STRING || swcHelpers.typeOf(STRING);
 x: swcHelpers.typeOf(STRING1);
 r: swcHelpers.typeOf(foo);

crates/swc/tests/tsc-references/variadicTuples1_es2015.2.minified.js

@@ -8,13 +8,6 @@ function curry(f, ...a) {
     return (...b)=>f(...a, ...b)
     ;
 }
-function curry2(f, t, u) {
-    return f(...t, ...u);
-}
-function callApi(method) {
-    return (...args)=>method(...args, {})
-    ;
-}
 concat([], []), concat([
     'hello'
 ], [
@@ -52,22 +45,26 @@ concat([], []), concat([
     [
         'def'
     ]
-]), curry((a, b, c, d)=>0
+]);
-), curry((a, b, c, d)=>0
+const fn1 = (a, b, c, d)=>0
-, 1), curry((a, b, c, d)=>0
+;
-, 1, 'abc'), curry((a, b, c, d)=>0
+curry(fn1), curry(fn1, 1), curry(fn1, 1, 'abc'), curry(fn1, 1, 'abc', !0), curry(fn1, 1, 'abc', !0, [
-, 1, 'abc', !0), curry((a, b, c, d)=>0
-, 1, 'abc', !0, [
     'x',
     'y'
-]), curry((x, b, ...args)=>0
+]);
-), curry((x, b, ...args)=>0
+const fn2 = (x, b, ...args)=>0
-, 1), curry((x, b, ...args)=>0
+;
-, 1, !0), curry((x, b, ...args)=>0
+curry(fn2), curry(fn2, 1), curry(fn2, 1, !0), curry(fn2, 1, !0, 'abc', 'def');
-, 1, !0, 'abc', 'def'), curry((...args)=>0
+const fn3 = (...args)=>0
-), curry((...args)=>0
+;
-, 'abc', 'def'), curry((...args)=>0
+function curry2(f, t, u) {
-, ...sa), curry2(fn10, [
+    return f(...t, ...u);
+}
+function callApi(method) {
+    return (...args)=>method(...args, {})
+    ;
+}
+curry(fn3), curry(fn3, 'abc', 'def'), curry(fn3, ...sa), curry2(fn10, [
     'hello',
     42
 ], [

crates/swc_ecma_minifier/scripts/next/start2.sh

@@ -0,0 +1,50 @@
+#!/usr/bin/env bash
+#
+# Usage:
+# 
+#   From your clone of next.js, you can invoke this script like
+#
+#       /absolute/path/to/this/script.sh examples/foo
+#
+# This script will
+#
+#  - build native binary (`next-swc`)
+#  - install dependnecies using `yarn``
+#  - remove some dependencies (`next`, `react`, `react-dom`)
+#  - yarn next build examples/foo
+#  - yarn next start examples/foo
+set -eu
+
+SCRIPT_DIR="$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )"
+
+dir="$1"
+nextJsDir="$(pwd)"
+
+# Ensure that next-swc is up to date
+echo "----- ⚠️  Building next-swc"
+(cd ./packages/next-swc && yarn build-native)
+
+# Install dependencies
+echo "----- ⚠️  Installing dependencies"
+if [ ! -d "$dir/node_modules" ]; then
+    if test -f "$dir/yarn.lock"; then
+        echo "  Using yarn"
+        # (cd $dir && yarn)
+    else
+        echo "  Using yarn"
+        # (cd $dir && npm ci)
+    fi
+fi
+
+
+echo "----- ⚠️  Removing cache"
+(cd $dir && rm -rf .next)
+
+echo "----- ⚠️  Replacing swc binary"
+mv packages/next-swc/native/*.node $dir/../node_modules/@next/swc-*/
+ls -alh $dir/../node_modules/@next/swc-*/
+
+# Build and start
+echo "----- ⚠️  Building the app using next"
+(cd $dir && npx next build)
+(cd $dir && npx next start)

crates/swc_ecma_minifier/src/compress/optimize/inline.rs

@@ -157,7 +157,10 @@ where
                             op: op!("!"), arg, ..
                         }) => arg.is_lit(),
                         Expr::This(..) => usage.is_fn_local,
-                        Expr::Arrow(arr) => is_arrow_simple_enough_for_copy(arr),
+                        Expr::Arrow(arr) => {
+                            !(usage.used_as_arg && usage.ref_count > 1)
+                                && is_arrow_simple_enough_for_copy(arr)
+                        }
                         _ => false,
                     }
                 {
@@ -251,7 +254,7 @@ where
                     }
 
                     if usage.used_as_arg && !usage.is_fn_local {
-                        if let Expr::Fn(..) = &**init {
+                        if let Expr::Fn(..) | Expr::Arrow(..) = &**init {
                             return;
                         }
                     }
@@ -466,7 +469,12 @@ where
 
         if let Some(usage) = self.data.vars.get(&i.to_id()) {
             if usage.declared_as_catch_param {
-                log_abort!("inline: [x] Declared as a catch parameter");
+                log_abort!("inline: Declared as a catch parameter");
+                return;
+            }
+
+            if usage.used_as_arg && usage.ref_count > 1 {
+                log_abort!("inline: Used as an arugment");
                 return;
             }
 

crates/swc_ecma_minifier/tests/TODO.txt

@@ -1,23 +1,13 @@
 asm/asm_mixed/input.js
 collapse_vars/collapse_vars_do_while/input.js
-collapse_vars/collapse_vars_lvalues/input.js
-collapse_vars/collapse_vars_lvalues_drop_assign/input.js
 collapse_vars/collapse_vars_misc1/input.js
-collapse_vars/collapse_vars_short_circuited_conditions/input.js
-collapse_vars/collapse_vars_side_effects_2/input.js
 collapse_vars/issue_2497/input.js
-conditionals/ifs_5/input.js
 drop_unused/keep_assign/input.js
 drop_unused/reassign_const/input.js
 drop_unused/var_catch_toplevel/input.js
 evaluate/issue_2535_1/input.js
 harmony/array_literal_with_spread_4a/input.js
-harmony/default_assign/input.js
-if_return/if_var_return/input.js
 inline/dont_inline_funcs_into_default_param_2/input.js
-inline/inline_into_scope_conflict/input.js
-issue_1034/non_hoisted_function_after_return_2a/input.js
-issue_1034/non_hoisted_function_after_return_2b/input.js
 issue_1052/defun_else_if_return/input.js
 issue_1052/defun_if_return/input.js
 issue_281/inner_var_for_in_1/input.js

crates/swc_ecma_minifier/tests/golden.txt

@@ -532,6 +532,7 @@ expression/pow_with_parentheses/input.js
 expression/pow_with_unary_between_brackets/input.js
 functions/avoid_generating_duplicate_functions_compared_together/input.js
 functions/avoid_generating_duplicate_functions_compared_together_2/input.js
+functions/avoid_generating_duplicate_functions_compared_together_3/input.js
 functions/avoid_generating_duplicate_functions_compared_together_4/input.js
 functions/deduplicate_parenthesis/input.js
 functions/drop_lone_use_strict/input.js

crates/swc_ecma_minifier/tests/postponed.txt

@@ -39,11 +39,15 @@ collapse_vars/collapse_vars_assignment/input.js
 collapse_vars/collapse_vars_constants/input.js
 collapse_vars/collapse_vars_do_while_drop_assign/input.js
 collapse_vars/collapse_vars_if/input.js
+collapse_vars/collapse_vars_lvalues/input.js
+collapse_vars/collapse_vars_lvalues_drop_assign/input.js
 collapse_vars/collapse_vars_object/input.js
 collapse_vars/collapse_vars_repeated/input.js
 collapse_vars/collapse_vars_self_reference/input.js
 collapse_vars/collapse_vars_short_circuit/input.js
+collapse_vars/collapse_vars_short_circuited_conditions/input.js
 collapse_vars/collapse_vars_side_effects_1/input.js
+collapse_vars/collapse_vars_side_effects_2/input.js
 collapse_vars/collapse_vars_switch/input.js
 collapse_vars/collapse_vars_unary/input.js
 collapse_vars/cond_branch_1/input.js
@@ -91,6 +95,7 @@ collapse_vars/var_defs/input.js
 collapse_vars/var_side_effects_2/input.js
 conditionals/equality_conditionals_false/input.js
 conditionals/hoist_decl/input.js
+conditionals/ifs_5/input.js
 conditionals/ifs_6/input.js
 conditionals/ifs_same_consequent/input.js
 conditionals/issue_1154/input.js
@@ -210,7 +215,6 @@ export/name_cache_import_star_as_name_from_module/input.js
 export/name_cache_mangle_export_default_class/input.js
 export/name_cache_mangle_export_default_function/input.js
 export/name_cache_mangle_local_import_and_export_aliases/input.js
-functions/avoid_generating_duplicate_functions_compared_together_3/input.js
 functions/duplicate_arg_var/input.js
 functions/empty_body/input.js
 functions/hoist_funs/input.js
@@ -280,6 +284,7 @@ harmony/array_spread_of_sequence/input.js
 harmony/class_name_can_be_mangled/input.js
 harmony/class_name_can_be_preserved_with_reserved/input.js
 harmony/classes_extending_classes_out_of_pure_iifes/input.js
+harmony/default_assign/input.js
 harmony/expansion/input.js
 harmony/fat_arrow_as_param/input.js
 harmony/import_statement_mangling/input.js
@@ -335,14 +340,18 @@ ie8/issue_2254_1/input.js
 ie8/issue_2254_2/input.js
 ie8/reduce_vars/input.js
 if_return/if_return_same_value/input.js
+if_return/if_var_return/input.js
 if_return/issue_2747/input.js
 if_return/issue_512/input.js
 inline/do_not_repeat_when_variable_larger_than_inlined_node/input.js
 inline/inline_annotation/input.js
+inline/inline_into_scope_conflict/input.js
 inline/inline_within_extends_1/input.js
 inline/inline_within_extends_2/input.js
 issue_1034/non_hoisted_function_after_return/input.js
+issue_1034/non_hoisted_function_after_return_2a/input.js
 issue_1034/non_hoisted_function_after_return_2a_strict/input.js
+issue_1034/non_hoisted_function_after_return_2b/input.js
 issue_1034/non_hoisted_function_after_return_2b_strict/input.js
 issue_1034/non_hoisted_function_after_return_strict/input.js
 issue_1052/deeply_nested/input.js

crates/swc_ecma_minifier/tests/terser_exec.rs

@@ -34,7 +34,6 @@ use testing::assert_eq;
 #[testing::fixture(
     "tests/terser/compress/**/input.js",
     exclude(
-        "functions/avoid_generating_duplicate_functions_compared_together_3/",
         // We don't care about ie8
         "ie8",
         // tests with infinite loops