✨ Improve ordering of missing patterns

Author: fruno-bulax

compiler-core/src/exhaustiveness/missing_patterns.rs

@@ -1,8 +1,8 @@
 use super::{CompileCaseResult, Decision, FallbackCheck, RuntimeCheck, Variable, printer::Printer};
 use crate::type_::environment::Environment;
 use ecow::EcoString;
-use itertools::Itertools;
-use std::collections::{HashMap, HashSet};
+use indexmap::IndexSet;
+use std::collections::HashMap;
 
 /// Returns a list of patterns not covered by the match expression.
 pub fn missing_patterns(
@@ -12,11 +12,8 @@ pub fn missing_patterns(
     let subjects = &result.compiled_case.subject_variables;
     let mut generator = MissingPatternsGenerator::new(subjects, environment);
     generator.add_missing_patterns(&result.compiled_case.tree);
-    let mut missing = generator.missing.into_iter().collect_vec();
 
-    // Sorting isn't necessary, but it makes it a bit easier to write tests.
-    missing.sort();
-    missing
+    generator.missing.into_iter().collect()
 }
 
 #[derive(Debug, Clone)]
@@ -67,7 +64,7 @@ impl Term {
 struct MissingPatternsGenerator<'a, 'env> {
     subjects: &'a Vec<Variable>,
     terms: Vec<Term>,
-    missing: HashSet<EcoString>,
+    missing: IndexSet<EcoString>,
     environment: &'a Environment<'env>,
     printer: Printer<'a>,
 }
@@ -77,7 +74,7 @@ impl<'a, 'env> MissingPatternsGenerator<'a, 'env> {
         MissingPatternsGenerator {
             subjects,
             terms: vec![],
-            missing: HashSet::new(),
+            missing: IndexSet::new(),
             environment,
             printer: Printer::new(&environment.names),
         }
@@ -113,6 +110,7 @@ impl<'a, 'env> MissingPatternsGenerator<'a, 'env> {
                     _ = mapping.insert(step.variable().id, index);
                 }
                 let pattern = self.print_terms(mapping);
+
                 _ = self.missing.insert(pattern);
             }
 

compiler-core/src/language_server/tests/snapshots/gleam_core__language_server__tests__action__add_missing_patterns_bool.snap

@@ -14,7 +14,7 @@ pub fn main(bool: Bool) {
 
 pub fn main(bool: Bool) {
   case bool {
-    False -> todo
     True -> todo
+    False -> todo
   }
 }

compiler-core/src/language_server/tests/snapshots/gleam_core__language_server__tests__action__add_missing_patterns_inline.snap

@@ -14,7 +14,7 @@ pub fn main(a: Bool) {
 
 pub fn main(a: Bool) {
   let value = case a {
-    False -> todo
     True -> todo
+    False -> todo
   }
 }

compiler-core/src/language_server/tests/snapshots/gleam_core__language_server__tests__action__add_missing_patterns_list.snap

@@ -20,10 +20,10 @@ pub fn main() {
   case list {
     [a, b, c, 4 as d] -> d
     [] -> todo
-    [_, _, _, _, _, ..] -> todo
-    [_, _, _, _] -> todo
-    [_, _, _] -> todo
-    [_, _] -> todo
     [_] -> todo
+    [_, _] -> todo
+    [_, _, _] -> todo
+    [_, _, _, _] -> todo
+    [_, _, _, _, _, ..] -> todo
   }
 }

compiler-core/src/language_server/tests/snapshots/gleam_core__language_server__tests__action__add_missing_patterns_multi.snap

@@ -18,7 +18,7 @@ pub fn main(a: Bool) {
 pub fn main(a: Bool) {
   let b = 1
   case a, b {
-    False, _ -> todo
     True, _ -> todo
+    False, _ -> todo
   }
 }

compiler-core/src/language_server/tests/snapshots/gleam_core__language_server__tests__action__inexhaustive_let_to_case_multi_variables.snap

@@ -14,9 +14,9 @@ pub fn main() {
   let #(var1, var2, var4) = case [1, 2, 3, 4] {
     [var1, var2, _var3, var4] -> #(var1, var2, var4)
     [] -> todo
-    [_, _, _, _, _, ..] -> todo
-    [_, _, _] -> todo
-    [_, _] -> todo
     [_] -> todo
+    [_, _] -> todo
+    [_, _, _] -> todo
+    [_, _, _, _, _, ..] -> todo
   }
 }

compiler-core/src/type_/tests/snapshots/gleam_core__type___tests__errors__inexhaustive_use_reports_error.snap

@@ -21,9 +21,9 @@ one of the other values is used then the assignment will crash.
 The missing patterns are:
 
     []
-    [_, _, _, _, ..]
-    [_, _, _]
-    [_, _]
     [_]
+    [_, _]
+    [_, _, _]
+    [_, _, _, _, ..]
 
 Hint: Use a more general pattern or use `let assert` instead.

compiler-core/src/type_/tests/snapshots/gleam_core__type___tests__exhaustiveness__custom_2.snap

@@ -35,5 +35,5 @@ is run on one of the values without a pattern then it will crash.
 
 The missing patterns are:
 
-    Three(Three(_))
     Three(Two)
+    Three(Three(_))

compiler-core/src/type_/tests/snapshots/gleam_core__type___tests__exhaustiveness__empty_case_of_bool.snap

@@ -21,5 +21,5 @@ is run on one of the values without a pattern then it will crash.
 
 The missing patterns are:
 
-    False
     True
+    False

compiler-core/src/type_/tests/snapshots/gleam_core__type___tests__exhaustiveness__empty_case_of_multi_pattern.snap

@@ -21,5 +21,5 @@ is run on one of the values without a pattern then it will crash.
 
 The missing patterns are:
 
-    Error(_), _
     Ok(_), _
+    Error(_), _