Fix spelling suggestions involving Unicode characters

internal/core/core.go

@@ -557,17 +557,17 @@ func GetScriptKindFromFileName(fileName string) ScriptKind {
 //
 // @internal
 func GetSpellingSuggestion[T any](name string, candidates iter.Seq[T], getName func(T) string, compare func(T, T) int) T {
-	maximumLengthDifference := max(2, int(float64(len(name))*0.34))
-	bestDistance := math.Floor(float64(len(name))*0.4) + 0.9 // If the best result is worse than this, don't bother.
 	runeName := []rune(name)
+	maximumLengthDifference := max(2, int(float64(len(runeName))*0.34))
+	bestDistance := math.Floor(float64(len(runeName))*0.4) + 0.9 // If the best result is worse than this, don't bother.
 	buffers := levenshteinBuffersPool.Get().(*levenshteinBuffers)
 	defer levenshteinBuffersPool.Put(buffers)
 	var bestCandidate T
 	hasBest := false
 	for candidate := range candidates {
 		candidateName := getName(candidate)
-		maxLen := max(len(candidateName), len(name))
-		minLen := min(len(candidateName), len(name))
+		maxLen := max(len(candidateName), len(runeName))
+		minLen := min(len(candidateName), len(runeName))
 		if candidateName != "" && maxLen-minLen <= maximumLengthDifference {
 			if candidateName == name {
 				continue

testdata/baselines/reference/compiler/unicodeSpellingSuggestions.errors.txt

@@ -0,0 +1,32 @@
+unicodeSpellingSuggestions.ts(3,1): error TS1435: Unknown keyword or identifier. Did you mean 'class'?
+unicodeSpellingSuggestions.ts(3,1): error TS2304: Cannot find name 'classAé'.
+unicodeSpellingSuggestions.ts(6,1): error TS1435: Unknown keyword or identifier. Did you mean 'class Aéé'?
+unicodeSpellingSuggestions.ts(6,1): error TS2304: Cannot find name 'classAéé'.
+unicodeSpellingSuggestions.ts(9,1): error TS1435: Unknown keyword or identifier. Did you mean 'class Aééé'?
+unicodeSpellingSuggestions.ts(9,1): error TS2304: Cannot find name 'classAééé'.
+
+
+==== unicodeSpellingSuggestions.ts (6 errors) ====
+    // https://github.com/microsoft/typescript-go/issues/4223
+
+    classAé {
+    ~~~~~~~
+!!! error TS1435: Unknown keyword or identifier. Did you mean 'class'?
+    ~~~~~~~
+!!! error TS2304: Cannot find name 'classAé'.
+    }
+
+    classAéé {
+    ~~~~~~~~
+!!! error TS1435: Unknown keyword or identifier. Did you mean 'class Aéé'?
+    ~~~~~~~~
+!!! error TS2304: Cannot find name 'classAéé'.
+    }
+
+    classAééé {
+    ~~~~~~~~~
+!!! error TS1435: Unknown keyword or identifier. Did you mean 'class Aééé'?
+    ~~~~~~~~~
+!!! error TS2304: Cannot find name 'classAééé'.
+    }
+

testdata/baselines/reference/compiler/unicodeSpellingSuggestions.symbols

@@ -0,0 +1,15 @@
+//// [tests/cases/compiler/unicodeSpellingSuggestions.ts] ////
+
+=== unicodeSpellingSuggestions.ts ===
+
+// https://github.com/microsoft/typescript-go/issues/4223
+
+classAé {
+}
+
+classAéé {
+}
+
+classAééé {
+}
+

testdata/baselines/reference/compiler/unicodeSpellingSuggestions.types

@@ -0,0 +1,17 @@
+//// [tests/cases/compiler/unicodeSpellingSuggestions.ts] ////
+
+=== unicodeSpellingSuggestions.ts ===
+// https://github.com/microsoft/typescript-go/issues/4223
+
+classAé {
+>classAé : any
+}
+
+classAéé {
+>classAéé : any
+}
+
+classAééé {
+>classAééé : any
+}
+

testdata/tests/cases/compiler/unicodeSpellingSuggestions.ts

@@ -0,0 +1,12 @@
+// @noEmit: true
+
+// https://github.com/microsoft/typescript-go/issues/4223
+
+classAé {
+}
+
+classAéé {
+}
+
+classAééé {
+}