Reject return statement in static block, even if AllowReturnOutsideFunction is used

Author: adams85

src/Acornima/Parser.State.cs

@@ -272,6 +272,14 @@ private bool CanAwait
         }
     }
 
+    private bool AllowReturn
+    {
+        // https://github.com/acornjs/acorn/blob/2e1550534005a8d02030df99e20f06c0392ac28b/acorn/src/state.js > `get allowReturn`
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        get => InFunction || (_options.AllowReturnOutsideFunction && (CurrentVarScope._flags & ScopeFlags.Top) != 0);
+    }
+
     private bool AllowSuper
     {
         // https://github.com/acornjs/acorn/blob/8.11.3/acorn/src/state.js > `get allowSuper`

src/Acornima/Parser.Statement.cs

@@ -743,7 +743,7 @@ private ReturnStatement ParseReturnStatement(in Marker startMarker)
     {
         // https://github.com/acornjs/acorn/blob/8.11.3/acorn/src/statement.js > `pp.parseReturnStatement = function`
 
-        if (!_options._allowReturnOutsideFunction && !InFunction)
+        if (!AllowReturn)
         {
             // Raise(_tokenizer._start, "'return' outside of function"); // original acornjs error reporting
             Raise(_tokenizer._start, IllegalReturn);

test/Acornima.Tests/ParserTests.cs

@@ -2278,6 +2278,18 @@ public void ShouldDisallowImportKeywordInYieldExpression(string sourceType)
         Assert.Throws<SyntaxErrorException>(() => parseAction(parser, code));
     }
 
+    [Fact]
+    public void ShouldDisallowReturnInClassStaticBlock()
+    {
+        var parser = new Parser(new ParserOptions
+        {
+            AllowReturnOutsideFunction = true,
+        });
+
+        var ex = Assert.Throws<SyntaxErrorException>(() => parser.ParseScript("class X { static { return; } }"));
+        Assert.Equal("Illegal return statement", ex.Description);
+    }
+
     [Theory]
     [InlineData("as")]
     [InlineData("do")]