Add some tests (#45230)

src/Compilers/CSharp/Test/Semantic/Semantics/RecordTests.cs

@@ -6804,6 +6804,11 @@ .maxstack  3
             Assert.Same(symbol.ContainingSymbol, model.GetEnclosingSymbol(x.SpanStart));
             Assert.Contains(symbol, model.LookupSymbols(x.SpanStart, name: "X"));
             Assert.Contains("X", model.LookupNames(x.SpanStart));
+
+            var baseWithargs = tree.GetRoot().DescendantNodes().OfType<SimpleBaseTypeSyntax>().Single();
+            Assert.Equal("Base(X, Y)", baseWithargs.ToString());
+            Assert.Null(model.GetTypeInfo(baseWithargs).Type);
+            Assert.Null(model.GetSymbolInfo(baseWithargs).Symbol);
         }
 
         [Fact]

src/Compilers/CSharp/Test/Semantic/Semantics/TopLevelStatementsTests.cs

@@ -36,6 +36,9 @@ public void Simple_01()
             Assert.True(entryPoint.ReturnsVoid);
             AssertEntryPointParameter(entryPoint);
             CompileAndVerify(comp, expectedOutput: "Hi!");
+            Assert.Same(entryPoint, comp.GetEntryPoint(default));
+            Assert.False(entryPoint.CanBeReferencedByName);
+            Assert.False(entryPoint.ContainingType.CanBeReferencedByName);
         }
 
         private static void AssertEntryPointParameter(SynthesizedSimpleProgramEntryPointSymbol entryPoint)