Fix literal_only_boolean_expressions Adjacent-Strings False-Positives

Change-Id: Ia3798ed4ba7e6128ad4e86458b9240918d7bedef
Bug: #61903
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/461560
Commit-Queue: Brian Wilkerson <brianwilkerson@google.com>
Reviewed-by: Samuel Rawlins <srawlins@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Auto-Submit: Rohit Saily <hello@rohitsaily.com>

Author: RohitSaily

pkg/linter/lib/src/rules/literal_only_boolean_expressions.dart

@@ -17,7 +17,7 @@ const _desc = r'Boolean expression composed only with literals.';
 bool _onlyLiterals(Expression? rawExpression) {
   var expression = rawExpression?.unParenthesized;
   if (expression is Literal) {
-    return expression is! StringInterpolation ||
+    return expression is! StringLiteral ||
         expression.computeConstantValue() != null;
   }
   if (expression is PrefixExpression) {

pkg/linter/test/rules/literal_only_boolean_expressions_test.dart

@@ -17,6 +17,26 @@ class LiteralOnlyBooleanExpressionsTest extends LintRuleTest {
   @override
   String get lintRule => LintNames.literal_only_boolean_expressions;
 
+  test_adjacent_string_interpolation_constant() async {
+    await assertDiagnostics(
+      r'''
+void f() {
+  const a = 20;
+  if ('$a' '0' == 20) {}
+}
+''',
+      [lint(29, 22)],
+    );
+  }
+
+  test_adjacent_string_interpolation_nonconstant() async {
+    await assertNoDiagnostics(r'''
+void f(int a) {
+  if ('$a' '0' == 20) {}
+}
+''');
+  }
+
   test_doWhile_false() async {
     await assertDiagnostics(
       r'''