refactor(es/minifier): Simplify analyzer context (#8164)

crates/swc/tests/fixture/issues-5xxx/5112/output/index.js

@@ -1,8 +1,8 @@
 function c(r, n) {
-    let e = new Uint8Array(4 * r * r), c = (r - n) / 2;
+    let e = new Uint8Array(4 * r * r);
     return {
         e,
         s: Math.sqrt(1.25),
-        c
+        c: (r - n) / 2
     };
 }

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

@@ -2,19 +2,19 @@
 // https://github.com/microsoft/TypeScript/pull/41094#issuecomment-716044363
 {
     let b, a = 0;
-    [{ 1: b } = [
+    [{ [a = 1]: b } = [
         9,
         a
     ]] = [];
 }{
     let b, a = 1;
     [{ [a]: b } = [
         9,
-        0
+        a = 0
     ]] = [];
 }{
     let b, a = 0;
-    [{ 1: b } = [
+    [{ [a = 1]: b } = [
         9,
         a
     ]] = [
@@ -26,7 +26,7 @@
 }{
     let b, a = 1;
     [{ [a]: b } = [
-        0,
+        a = 0,
         9
     ]] = [
         [
@@ -37,19 +37,19 @@
 }// same as above but on left of a binary expression
 {
     let b, a = 0;
-    [{ 1: b } = [
+    [{ [a = 1]: b } = [
         9,
         a
     ]] = [], f();
 }{
     let b, a = 1;
     [{ [a]: b } = [
         9,
-        0
+        a = 0
     ]] = [], f();
 }{
     let b, a = 0;
-    [{ 1: b } = [
+    [{ [a = 1]: b } = [
         9,
         a
     ]] = [
@@ -61,7 +61,7 @@
 }{
     let b, a = 1;
     [{ [a]: b } = [
-        0,
+        a = 0,
         9
     ]] = [
         [
@@ -72,19 +72,19 @@
 }// same as above but on right of a binary expression
 {
     let b, a = 0;
-    f(), [{ 1: b } = [
+    f(), [{ [a = 1]: b } = [
         9,
         a
     ]] = [];
 }{
     let b, a = 1;
     f(), [{ [a]: b } = [
         9,
-        0
+        a = 0
     ]] = [];
 }{
     let b, a = 0;
-    f(), [{ 1: b } = [
+    f(), [{ [a = 1]: b } = [
         9,
         a
     ]] = [
@@ -96,7 +96,7 @@
 }{
     let b, a = 1;
     f(), [{ [a]: b } = [
-        0,
+        a = 0,
         9
     ]] = [
         [

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

@@ -1,3 +1,3 @@
 //// [genericInstantiationEquivalentToObjectLiteral.ts]
-var y;
-f(y), f(y), f2(y), f2(y);
+var x, y;
+y = x = y, f(x), f(y), f2(x), f2(y);

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

@@ -77,12 +77,11 @@ var { removed } = removable;
 _object_without_properties(removable, [
     "removed"
 ]);
-let computed = 'b', computed2 = 'a';
-var { [computed]: stillNotGreat, [computed2]: soSo } = o, o = _object_without_properties(o, [
-    computed,
-    computed2
+var { b: stillNotGreat, a: soSo } = o, o = _object_without_properties(o, [
+    'b',
+    'a'
 ].map(_to_property_key));
 o = _object_without_properties(_o = o, [
-    computed,
-    computed2
-].map(_to_property_key)), { [computed]: stillNotGreat, [computed2]: soSo } = _o;
+    'b',
+    'a'
+].map(_to_property_key)), { b: stillNotGreat, a: soSo } = _o;

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

@@ -3,7 +3,7 @@
 import { _ as _class_call_check } from "@swc/helpers/_/_class_call_check";
 import { _ as _inherits } from "@swc/helpers/_/_inherits";
 import { _ as _create_super } from "@swc/helpers/_/_create_super";
-var a, C = function C(x) {
+var i, a, C = function C(x) {
     return _class_call_check(this, C), x;
 };
-new C("a"), new C("hi"), new a("bye"), new a("hm");
+new C("a"), a = i = a, new C("hi"), new i("bye"), new a("hm");

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

@@ -902,7 +902,7 @@ impl Optimizer<'_> {
                 if let Some(usage) = self.data.vars.get(&orig_params[idx].to_id()) {
                     if usage.ref_count == 1
                         && !usage.reassigned
-                        && !usage.has_property_mutation
+                        && usage.property_mutation_count == 0
                         && matches!(
                             &*arg,
                             Expr::Lit(

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

@@ -176,6 +176,7 @@ impl Optimizer<'_> {
                 && usage.declared_count == 1
                 && usage.assign_count == 1
                 && !usage.reassigned
+                && (usage.property_mutation_count == 0 || !usage.reassigned)
                 && match init {
                     Expr::Ident(Ident { sym, .. }) if &**sym == "eval" => false,
 
@@ -238,7 +239,7 @@ impl Optimizer<'_> {
                     Expr::This(..) => usage.is_fn_local,
                     Expr::Arrow(arr) => {
                         is_arrow_simple_enough_for_copy(arr)
-                            && !(usage.has_property_mutation
+                            && !(usage.property_mutation_count > 0
                                 || usage.executed_multiple_time
                                 || usage.used_as_arg && ref_count > 1)
                             && ref_count - 1 <= usage.callee_count
@@ -254,7 +255,7 @@ impl Optimizer<'_> {
                     indexed_with_dynamic_key,
                     usage_count,
                     has_property_access,
-                    has_property_mutation,
+                    property_mutation_count,
                     used_above_decl,
                     executed_multiple_time,
                     used_in_cond,
@@ -269,7 +270,7 @@ impl Optimizer<'_> {
                             u.used_as_ref |= used_as_ref;
                             u.indexed_with_dynamic_key |= indexed_with_dynamic_key;
                             u.has_property_access |= has_property_access;
-                            u.has_property_mutation |= has_property_mutation;
+                            u.property_mutation_count += property_mutation_count;
                             u.used_above_decl |= used_above_decl;
                             u.executed_multiple_time |= executed_multiple_time;
                             u.used_in_cond |= used_in_cond;
@@ -433,7 +434,10 @@ impl Optimizer<'_> {
                     _ => {
                         for id in idents_used_by(init) {
                             if let Some(v_usage) = self.data.vars.get(&id) {
-                                if v_usage.reassigned || v_usage.has_property_mutation {
+                                if v_usage.reassigned
+                                    || v_usage.property_mutation_count
+                                        > usage.property_mutation_count
+                                {
                                     return;
                                 }
                             }
@@ -692,8 +696,7 @@ impl Optimizer<'_> {
             //
             if (self.options.reduce_vars || self.options.collapse_vars || self.options.inline != 0)
                 && usage.ref_count == 1
-                && (usage.can_inline_fn_once())
-                && !usage.inline_prevented
+                && usage.can_inline_fn_once()
                 && (match decl {
                     Decl::Class(..) => !usage.used_above_decl,
                     Decl::Fn(..) => true,

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

@@ -2890,6 +2890,10 @@ impl VisitMut for Optimizer<'_> {
             if init.is_invalid() {
                 var.init = None
             }
+
+            if id.is_dummy() {
+                var.name = Pat::dummy();
+            }
         };
 
         self.store_var_for_prop_hoisting(var);
@@ -2902,8 +2906,6 @@ impl VisitMut for Optimizer<'_> {
     #[cfg_attr(feature = "debug", tracing::instrument(skip_all))]
     fn visit_mut_var_declarators(&mut self, vars: &mut Vec<VarDeclarator>) {
         vars.retain_mut(|var| {
-            let had_init = var.init.is_some();
-
             if var.name.is_invalid() {
                 self.changed = true;
                 return false;
@@ -2917,12 +2919,6 @@ impl VisitMut for Optimizer<'_> {
                 return false;
             }
 
-            // It will be inlined.
-            if had_init && var.init.is_none() {
-                self.changed = true;
-                return false;
-            }
-
             debug_assert_valid(&*var);
 
             true

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

@@ -151,7 +151,7 @@ impl Optimizer<'_> {
             if v.ref_count == 0
                 && v.usage_count == 0
                 && !v.reassigned
-                && !v.has_property_mutation
+                && v.property_mutation_count == 0
                 && !v.declared_as_catch_param
             {
                 self.changed = true;
@@ -435,7 +435,7 @@ impl Optimizer<'_> {
                     .data
                     .vars
                     .get(&ident.to_id())
-                    .map(|v| v.usage_count == 0 && !v.has_property_mutation)
+                    .map(|v| v.usage_count == 0 && v.property_mutation_count == 0)
                     .unwrap_or(false)
                 {
                     self.changed = true;
@@ -475,7 +475,7 @@ impl Optimizer<'_> {
                     .data
                     .vars
                     .get(&ident.to_id())
-                    .map(|v| v.usage_count == 0 && !v.has_property_mutation)
+                    .map(|v| v.usage_count == 0 && v.property_mutation_count == 0)
                     .unwrap_or(false)
                 {
                     self.changed = true;