revert(ls): drop completions guards to keep PR scoped to autoimports (#1691)

Author: arash-mosavi

internal/ls/completions.go

@@ -2376,14 +2376,7 @@ var wordSeparators = collections.NewSetFromItems(
 // e.g. for "abc def.ghi|jkl", the word length is 3 and the word start is 'g'.
 func getWordLengthAndStart(sourceFile *ast.SourceFile, position int) (wordLength int, wordStart rune) {
 	// !!! Port other case of vscode's `DEFAULT_WORD_REGEXP` that covers words that start like numbers, e.g. -123.456abcd.
-
-	// Bounds check to prevent slice bounds out of range panic
-	sourceText := sourceFile.Text()
-	if position < 0 || position > len(sourceText) {
-		return 0, 0
-	}
-
-	text := sourceText[:position]
+	text := sourceFile.Text()[:position]
 	totalSize := 0
 	var firstRune rune
 	for r, size := utf8.DecodeLastRuneInString(text); size != 0; r, size = utf8.DecodeLastRuneInString(text[:len(text)-totalSize]) {
@@ -2492,13 +2485,7 @@ func getFilterText(
 
 // Ported from vscode's `provideCompletionItems`.
 func getDotAccessor(file *ast.SourceFile, position int) string {
-	// Bounds check to prevent slice bounds out of range panic
-	fileText := file.Text()
-	if position < 0 || position > len(fileText) {
-		return ""
-	}
-
-	text := fileText[:position]
+	text := file.Text()[:position]
 	totalSize := 0
 	if strings.HasSuffix(text, "?.") {
 		totalSize += 2