Add methodsof to type info (#1303)

Add `methodsof` to type info for struct, union and bitstruct

test/unit/regression/methodsof.c3

@@ -0,0 +1,78 @@
+module methodsof;
+
+interface IBar
+{
+    fn void fnA();
+    fn void fnB();
+}
+struct Bar (IBar)
+{
+    int a;
+}
+fn void Bar.fnB(&self) @dynamic {}
+fn void Bar.fnA(&self) @dynamic {}
+
+struct Foo
+{
+    int i;
+    bool b;
+}
+
+fn void Foo.foo(&self) {}
+fn int Foo.bar(&self, int x) { return x * self.i; }
+fn bool Foo.xyz(&self) { return self.b; }
+
+struct NoMethods
+{
+    int a;
+}
+
+bitstruct BazBits : char
+{
+    int a : 0..2;
+    int b : 4..6;
+    bool c : 7;
+}
+
+fn void BazBits.fn1(&self) {}
+fn void BazBits.fn2(&self) {}
+
+union AUnion {
+    int y;
+    double z;
+}
+
+fn void AUnion.a(&self) {}
+fn void AUnion.b(&self) {}
+
+
+module methodsof @test;
+
+import std::io;
+
+fn void methodsof() 
+{
+    assert(Foo.methodsof.len == 3);
+    assert(Bar.methodsof.len == 2);
+    assert(NoMethods.methodsof.len == 0);
+
+    assert(Foo.methodsof[0] == "foo");
+    assert(Foo.methodsof[1] == "bar");
+    assert(Foo.methodsof[2] == "xyz");
+    assert(Bar.methodsof[0] == "fnB");
+    assert(Bar.methodsof[1] == "fnA");
+
+    assert(BazBits.methodsof[0] == "fn1");
+    assert(BazBits.methodsof[1] == "fn2");
+
+    assert(AUnion.methodsof[0] == "a");
+    assert(AUnion.methodsof[1] == "b");
+
+    Foo foo = { .i = 4, .b = true };
+    assert(Foo.$eval(Foo.methodsof[2])(&foo) == true); // Foo.xyz
+    assert(Foo.$eval(Foo.methodsof[1])(&foo, 2) == 8); // Foo.bar
+
+    Foo foo2 = { .i = 2, .b = false };
+    assert(foo2.$eval(Foo.methodsof[2])() == false); // Foo.xyz
+    assert(foo2.$eval(Foo.methodsof[1])(10) == 20); // Foo.bar
+}