nandi.uk
Fork of daniellemaywood.uk/gleam — Wasm codegen work
use instanceof checks to check lists are empty in decision tree
author
Giacomo Cavalieri
committer
Louis Pilfold
date
(Apr 30, 2025, 3:47 PM +0100)
commit
0759376e
0759376e79beeeabb44131e51a82f7f911727efa
parent
f2c7eb94
f2c7eb94e4b6bc30d37f15dd463b632d436e2c01
+58
-30
+10
compiler-core/src/javascript.rs
+10
compiler-core/src/javascript.rs
···
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self.register_prelude_usage(&mut imports, "toList", None);
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};
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if self.tracker.list_empty_class_used {
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self.register_prelude_usage(&mut imports, "Empty", Some("$Empty"));
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};
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+
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if self.tracker.list_non_empty_class_used {
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self.register_prelude_usage(&mut imports, "NonEmpty", Some("$NonEmpty"));
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};
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+
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if self.tracker.prepend_used {
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self.register_prelude_usage(&mut imports, "prepend", Some("listPrepend"));
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};
···
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pub(crate) struct UsageTracker {
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pub ok_used: bool,
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pub list_used: bool,
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pub list_empty_class_used: bool,
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pub list_non_empty_class_used: bool,
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pub prepend_used: bool,
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pub error_used: bool,
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pub int_remainder_used: bool,
+8
-2
compiler-core/src/javascript/decision.rs
+8
-2
compiler-core/src/javascript/decision.rs
···
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docvec![var_value, " instanceof ", qualification, match_.name()]
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}
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-
RuntimeCheck::NonEmptyList { .. } => docvec!["!", var_value, ".hasLength(0)"],
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-
RuntimeCheck::EmptyList => docvec![var_value, ".hasLength(0)"],
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RuntimeCheck::NonEmptyList { .. } => {
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self.expression_generator.tracker.list_non_empty_class_used = true;
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docvec![var_value, " instanceof $NonEmpty"]
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}
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RuntimeCheck::EmptyList => {
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self.expression_generator.tracker.list_empty_class_used = true;
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docvec![var_value, " instanceof $Empty"]
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}
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}
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}
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+3
-3
compiler-core/src/javascript/tests/snapshots/gleam_core__javascript__tests__case__case_branches_guards_are_wrapped_in_parentheses.snap
+3
-3
compiler-core/src/javascript/tests/snapshots/gleam_core__javascript__tests__case__case_branches_guards_are_wrapped_in_parentheses.snap
···
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----- COMPILED JAVASCRIPT
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-
import { toList } from "../gleam.mjs";
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import { toList, Empty as $Empty } from "../gleam.mjs";
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function anything() {
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while (true) {
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let $ = toList([]);
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-
if ($.hasLength(0)) {
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if ($ instanceof $Empty) {
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} else {
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let pattern = $.tail;
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-
if (pattern.hasLength(0)) {
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if (pattern instanceof $Empty) {
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if (false || true) {
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let a = $.head;
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return a;
+5
-3
compiler-core/src/javascript/tests/snapshots/gleam_core__javascript__tests__case__guard_variable_only_brought_into_scope_when_needed.snap
+5
-3
compiler-core/src/javascript/tests/snapshots/gleam_core__javascript__tests__case__guard_variable_only_brought_into_scope_when_needed.snap
···
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----- COMPILED JAVASCRIPT
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import { Empty as $Empty } from "../gleam.mjs";
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+
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function go(x) {
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-
if (x.hasLength(0)) {
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if (x instanceof $Empty) {
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return 2;
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} else {
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let pattern = x.tail;
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-
if (pattern.hasLength(0)) {
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if (pattern instanceof $Empty) {
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return 2;
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} else {
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let pattern$1 = pattern.tail;
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-
if (pattern$1.hasLength(0)) {
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if (pattern$1 instanceof $Empty) {
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let a = x.head;
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if (a === 1) {
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let b = pattern.head;
+5
-5
compiler-core/src/javascript/tests/snapshots/gleam_core__javascript__tests__case__nested_string_prefix_match.snap
+5
-5
compiler-core/src/javascript/tests/snapshots/gleam_core__javascript__tests__case__nested_string_prefix_match.snap
···
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----- COMPILED JAVASCRIPT
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import { Ok, toList } from "../gleam.mjs";
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import { Ok, toList, Empty as $Empty } from "../gleam.mjs";
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function main() {
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let $ = new Ok(toList(["a", "b c", "d"]));
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let pattern = $[0];
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if (pattern.hasLength(0)) {
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if (pattern instanceof $Empty) {
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return 1;
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} else {
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let pattern$1 = pattern.tail;
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if (pattern$1.hasLength(0)) {
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if (pattern$1 instanceof $Empty) {
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return 1;
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} else {
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let pattern$2 = pattern$1.tail;
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-
if (pattern$2.hasLength(0)) {
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if (pattern$2 instanceof $Empty) {
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return 1;
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} else {
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let pattern$3 = pattern$2.tail;
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-
if (pattern$3.hasLength(0)) {
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+
if (pattern$3 instanceof $Empty) {
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let pattern$4 = pattern$2.head;
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if (pattern$4 === "d") {
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let pattern$5 = pattern$1.head;
+4
-4
compiler-core/src/javascript/tests/snapshots/gleam_core__javascript__tests__case__nested_string_prefix_match_that_would_crash_on_js.snap
+4
-4
compiler-core/src/javascript/tests/snapshots/gleam_core__javascript__tests__case__nested_string_prefix_match_that_would_crash_on_js.snap
···
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----- COMPILED JAVASCRIPT
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import { Ok, toList } from "../gleam.mjs";
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import { Ok, toList, Empty as $Empty } from "../gleam.mjs";
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function main() {
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let $ = new Ok(toList(["b c", "d"]));
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let pattern = $[0];
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if (pattern.hasLength(0)) {
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if (pattern instanceof $Empty) {
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return 1;
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} else {
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let pattern$1 = pattern.tail;
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if (pattern$1.hasLength(0)) {
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if (pattern$1 instanceof $Empty) {
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return 1;
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} else {
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let pattern$2 = pattern$1.tail;
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-
if (pattern$2.hasLength(0)) {
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if (pattern$2 instanceof $Empty) {
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let pattern$3 = pattern$1.head;
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if (pattern$3 === "d") {
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let pattern$4 = pattern.head;
+5
-3
compiler-core/src/javascript/tests/snapshots/gleam_core__javascript__tests__case_clause_guards__alternative_patterns_assignment.snap
+5
-3
compiler-core/src/javascript/tests/snapshots/gleam_core__javascript__tests__case_clause_guards__alternative_patterns_assignment.snap
···
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----- COMPILED JAVASCRIPT
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import { Empty as $Empty } from "../gleam.mjs";
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+
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export function main(xs) {
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if (xs.hasLength(0)) {
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if (xs instanceof $Empty) {
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return 1;
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} else {
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let pattern = xs.tail;
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if (pattern.hasLength(0)) {
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if (pattern instanceof $Empty) {
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let x = xs.head;
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return x;
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} else {
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let pattern$1 = pattern.tail;
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-
if (pattern$1.hasLength(0)) {
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if (pattern$1 instanceof $Empty) {
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let x = pattern.head;
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return x;
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} else {
+5
-3
compiler-core/src/javascript/tests/snapshots/gleam_core__javascript__tests__case_clause_guards__alternative_patterns_guard.snap
+5
-3
compiler-core/src/javascript/tests/snapshots/gleam_core__javascript__tests__case_clause_guards__alternative_patterns_guard.snap
···
12
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----- COMPILED JAVASCRIPT
15
+
import { Empty as $Empty } from "../gleam.mjs";
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+
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export function main(xs) {
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-
if (xs.hasLength(0)) {
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if (xs instanceof $Empty) {
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return 0;
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} else {
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let pattern = xs.tail;
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if (pattern.hasLength(0)) {
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if (pattern instanceof $Empty) {
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let x = xs.head;
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if (x === 1) {
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return x;
···
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}
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} else {
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let pattern$1 = pattern.tail;
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-
if (pattern$1.hasLength(0)) {
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if (pattern$1 instanceof $Empty) {
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let x = pattern.head;
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if (x === 1) {
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return x;
+5
-3
compiler-core/src/javascript/tests/snapshots/gleam_core__javascript__tests__case_clause_guards__alternative_patterns_list.snap
+5
-3
compiler-core/src/javascript/tests/snapshots/gleam_core__javascript__tests__case_clause_guards__alternative_patterns_list.snap
···
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----- COMPILED JAVASCRIPT
15
+
import { Empty as $Empty } from "../gleam.mjs";
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+
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export function main(xs) {
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-
if (xs.hasLength(0)) {
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if (xs instanceof $Empty) {
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return 1;
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} else {
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let pattern = xs.tail;
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-
if (pattern.hasLength(0)) {
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if (pattern instanceof $Empty) {
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let pattern$1 = xs.head;
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if (pattern$1 === 1) {
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return 0;
···
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}
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} else {
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let pattern$1 = pattern.tail;
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-
if (pattern$1.hasLength(0)) {
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+
if (pattern$1 instanceof $Empty) {
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let pattern$2 = pattern.head;
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if (pattern$2 === 2) {
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let pattern$3 = xs.head;
+3
-1
compiler-core/src/javascript/tests/snapshots/gleam_core__javascript__tests__functions__tail_call.snap
+3
-1
compiler-core/src/javascript/tests/snapshots/gleam_core__javascript__tests__functions__tail_call.snap
···
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----- COMPILED JAVASCRIPT
16
+
import { Empty as $Empty } from "../gleam.mjs";
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+
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export function count(loop$xs, loop$n) {
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while (true) {
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let xs = loop$xs;
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let n = loop$n;
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-
if (xs.hasLength(0)) {
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+
if (xs instanceof $Empty) {
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return n;
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} else {
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let xs$1 = xs.tail;
+5
-3
compiler-core/src/javascript/tests/snapshots/gleam_core__javascript__tests__lists__case.snap
+5
-3
compiler-core/src/javascript/tests/snapshots/gleam_core__javascript__tests__lists__case.snap
···
15
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----- COMPILED JAVASCRIPT
18
+
import { Empty as $Empty } from "../gleam.mjs";
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+
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function go(xs) {
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-
if (xs.hasLength(0)) {
21
+
if (xs instanceof $Empty) {
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return 0;
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} else {
22
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let pattern = xs.tail;
23
-
if (pattern.hasLength(0)) {
25
+
if (pattern instanceof $Empty) {
24
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return 1;
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} else {
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let pattern$1 = pattern.tail;
27
-
if (pattern$1.hasLength(0)) {
29
+
if (pattern$1 instanceof $Empty) {
28
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return 2;
29
31
} else {
30
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return 9999;