diff --git a/TODO.md b/TODO.md
index 91963ee..e5cc852 100644
--- a/TODO.md
+++ b/TODO.md
@@ -12,6 +12,7 @@
 - Also, check the codes for FIXME and TODO
 - Allocation is done using pointers for members, is this desired?
 - See if we want to replace Fractional with Real, and add Rational, Irrationl, Algebraic, Transendental
+  - Implement q32? q64? Two i32/i64 divided?
 - Does Subscript do what we want? It's a language feature rather a normal typed thing. How would you implement your own Subscript-able type?
   - Clean up Subscript implementation - it's half implemented in the compiler. Makes more sense to move more parts to stdlib_types.
 - Have a set of rules or guidelines for the constraint comments, they're messy.
diff --git a/phasm/compiler.py b/phasm/compiler.py
index 43e4edb..d4534f5 100644
--- a/phasm/compiler.py
+++ b/phasm/compiler.py
@@ -2,7 +2,7 @@
 This module contains the code to convert parsed Ourlang into WebAssembly code
 """
 import struct
-from typing import Dict, List, Optional
+from typing import List, Optional
 
 from . import codestyle, ourlang, prelude, wasm
 from .runtime import calculate_alloc_size, calculate_member_offset
@@ -292,15 +292,20 @@ def expression(wgn: WasmGenerator, inp: ourlang.Expression) -> None:
         expression(wgn, inp.left)
         expression(wgn, inp.right)
 
-        type_var_map: Dict[type3functions.TypeVariable, type3types.Type3] = {}
+        type_var_map: dict[type3functions.TypeVariable, type3types.Type3] = {}
 
         for type_var, arg_expr in zip(inp.operator.signature.args, [inp.left, inp.right, inp], strict=True):
-            if not isinstance(type_var, type3functions.TypeVariable):
+            assert arg_expr.type3 is not None, TYPE3_ASSERTION_ERROR
+
+            if isinstance(type_var, type3types.Type3):
                 # Fixed type, not part of the lookup requirements
                 continue
 
-            assert arg_expr.type3 is not None, TYPE3_ASSERTION_ERROR
-            type_var_map[type_var] = arg_expr.type3
+            if isinstance(type_var, type3functions.TypeVariable):
+                type_var_map[type_var] = arg_expr.type3
+                continue
+
+            raise NotImplementedError(type_var, arg_expr.type3)
 
         router = prelude.PRELUDE_TYPE_CLASS_INSTANCE_METHODS[inp.operator]
         router(wgn, type_var_map)
@@ -315,12 +320,17 @@ def expression(wgn: WasmGenerator, inp: ourlang.Expression) -> None:
             type_var_map = {}
 
             for type_var, arg_expr in zip(inp.function.signature.args, inp.arguments + [inp], strict=True):
-                if not isinstance(type_var, type3functions.TypeVariable):
+                assert arg_expr.type3 is not None, TYPE3_ASSERTION_ERROR
+
+                if isinstance(type_var, type3types.Type3):
                     # Fixed type, not part of the lookup requirements
                     continue
 
-                assert arg_expr.type3 is not None, TYPE3_ASSERTION_ERROR
-                type_var_map[type_var] = arg_expr.type3
+                if isinstance(type_var, type3functions.TypeVariable):
+                    type_var_map[type_var] = arg_expr.type3
+                    continue
+
+                raise NotImplementedError(type_var, arg_expr.type3)
 
             router = prelude.PRELUDE_TYPE_CLASS_INSTANCE_METHODS[inp.function]
             try:
diff --git a/phasm/prelude/__init__.py b/phasm/prelude/__init__.py
index d91128e..e269590 100644
--- a/phasm/prelude/__init__.py
+++ b/phasm/prelude/__init__.py
@@ -1,27 +1,33 @@
 """
 The prelude are all the builtin types, type classes and methods
 """
-from typing import Callable
+from typing import Any, Callable
 from warnings import warn
 
 from phasm.stdlib import types as stdtypes
 from phasm.wasmgenerator import Generator
 
-from ..type3.functions import TypeVariable
-from ..type3.routers import FunctionSignatureRouter
+from ..type3.functions import (
+    Constraint_TypeClassInstanceExists,
+    TypeConstructorVariable,
+    TypeVariable,
+    TypeVariableApplication_Nullary,
+)
+from ..type3.routers import TypeClassArgsRouter, TypeVariableLookup
 from ..type3.typeclasses import Type3Class, Type3ClassMethod
 from ..type3.types import (
     IntType3,
     Type3,
     TypeApplication_Nullary,
+    TypeConstructor_Base,
     TypeConstructor_StaticArray,
     TypeConstructor_Struct,
     TypeConstructor_Tuple,
 )
 
-PRELUDE_TYPE_CLASS_INSTANCES_EXISTING: set[tuple[Type3Class, tuple[Type3, ...]]] = set()
+PRELUDE_TYPE_CLASS_INSTANCES_EXISTING: set[tuple[Type3Class, tuple[Type3 | TypeConstructor_Base[Any], ...]]] = set()
 
-PRELUDE_TYPE_CLASS_INSTANCE_METHODS: dict[Type3ClassMethod, FunctionSignatureRouter[Generator, None]] = {}
+PRELUDE_TYPE_CLASS_INSTANCE_METHODS: dict[Type3ClassMethod, TypeClassArgsRouter[Generator, None]] = {}
 
 class MissingImplementationException(Exception):
     pass
@@ -31,18 +37,26 @@ class MissingImplementationWarning(Warning):
 
 def instance_type_class(
         cls: Type3Class,
-        *typ: Type3,
-        methods: dict[str, Callable[[Generator], None]] = {},
-        operators: dict[str, Callable[[Generator], None]] = {},
+        *typ: Type3 | TypeConstructor_Base[Any],
+        methods: dict[str, Callable[[Generator, TypeVariableLookup], None]] = {},
+        operators: dict[str, Callable[[Generator, TypeVariableLookup], None]] = {},
 ) -> None:
     global PRELUDE_TYPE_CLASS_INSTANCES_EXISTING
     global PRELUDE_TYPE_CLASS_INSTANCE_METHODS
 
     assert len(cls.args) == len(typ)
 
-    type_var_map = {}
+    tv_map: dict[TypeVariable, Type3] = {}
+    tc_map: dict[TypeConstructorVariable, TypeConstructor_Base[Any]] = {}
     for arg_tv, arg_tp in zip(cls.args, typ, strict=True):
-        type_var_map[arg_tv] = arg_tp
+        if isinstance(arg_tv, TypeVariable):
+            assert isinstance(arg_tp, Type3)
+            tv_map[arg_tv] = arg_tp
+        elif isinstance(arg_tv, TypeConstructorVariable):
+            assert isinstance(arg_tp, TypeConstructor_Base)
+            tc_map[arg_tv] = arg_tp
+        else:
+            raise NotImplementedError(arg_tv, arg_tp)
 
     # TODO: Check for required existing instantiations
 
@@ -51,7 +65,7 @@ def instance_type_class(
     for method_name, method in cls.methods.items():
         router = PRELUDE_TYPE_CLASS_INSTANCE_METHODS.get(method)
         if router is None:
-            router = FunctionSignatureRouter[Generator, None](method.signature)
+            router = TypeClassArgsRouter[Generator, None](cls.args)
             PRELUDE_TYPE_CLASS_INSTANCE_METHODS[method] = router
 
         try:
@@ -60,12 +74,12 @@ def instance_type_class(
             warn(MissingImplementationWarning(str(method), cls.name + ' ' + ' '.join(x.name for x in typ)))
             continue
 
-        router.add(type_var_map, generator)
+        router.add(tv_map, tc_map, generator)
 
     for operator_name, operator in cls.operators.items():
         router = PRELUDE_TYPE_CLASS_INSTANCE_METHODS.get(operator)
         if router is None:
-            router = FunctionSignatureRouter[Generator, None](operator.signature)
+            router = TypeClassArgsRouter[Generator, None](cls.args)
             PRELUDE_TYPE_CLASS_INSTANCE_METHODS[operator] = router
 
         try:
@@ -74,7 +88,7 @@ def instance_type_class(
             warn(MissingImplementationWarning(str(operator), cls.name + ' ' + ' '.join(x.name for x in typ)))
             continue
 
-        router.add(type_var_map, generator)
+        router.add(tv_map, tc_map, generator)
 
 none = Type3('none', TypeApplication_Nullary(None, None))
 """
@@ -195,11 +209,12 @@ PRELUDE_TYPES: dict[str, Type3] = {
     'bytes': bytes_,
 }
 
-a = TypeVariable('a')
-b = TypeVariable('b')
+a = TypeVariable('a', TypeVariableApplication_Nullary(None, None))
+b = TypeVariable('b', TypeVariableApplication_Nullary(None, None))
 
+t = TypeConstructorVariable('t')
 
-InternalPassAsPointer = Type3Class('InternalPassAsPointer', [a], methods={}, operators={})
+InternalPassAsPointer = Type3Class('InternalPassAsPointer', (a, ), methods={}, operators={})
 """
 Internal type class to keep track which types we pass arounds as a pointer.
 """
@@ -209,7 +224,7 @@ instance_type_class(InternalPassAsPointer, bytes_)
 # instance_type_class(InternalPassAsPointer, tuple_)
 # instance_type_class(InternalPassAsPointer, struct)
 
-Eq = Type3Class('Eq', [a], methods={}, operators={
+Eq = Type3Class('Eq', (a, ), methods={}, operators={
     '==': [a, a, bool_],
     '!=': [a, a, bool_],
     # FIXME: Do we want to expose 'eqz'? Or is that a compiler optimization?
@@ -248,7 +263,7 @@ instance_type_class(Eq, f64, operators={
     '!=': stdtypes.f64_eq_not_equals,
 })
 
-Ord = Type3Class('Ord', [a], methods={
+Ord = Type3Class('Ord', (a, ), methods={
     'min': [a, a, a],
     'max': [a, a, a],
 }, operators={
@@ -331,7 +346,7 @@ instance_type_class(Ord, f64, methods={
     '>=': stdtypes.f64_ord_greater_than_or_equal,
 })
 
-Bits = Type3Class('Bits', [a], methods={
+Bits = Type3Class('Bits', (a, ), methods={
     'shl': [a, u32, a], # Logical shift left
     'shr': [a, u32, a], # Logical shift right
     'rotl': [a, u32, a], # Rotate bits left
@@ -374,7 +389,7 @@ instance_type_class(Bits, u64, methods={
     '^': stdtypes.u64_bits_bitwise_xor,
 })
 
-NatNum = Type3Class('NatNum', [a], methods={}, operators={
+NatNum = Type3Class('NatNum', (a, ), methods={}, operators={
     '+': [a, a, a],
     '-': [a, a, a],
     '*': [a, a, a],
@@ -425,7 +440,7 @@ instance_type_class(NatNum, f64, operators={
     '>>': stdtypes.f64_natnum_arithmic_shift_right,
 })
 
-IntNum = Type3Class('IntNum', [a], methods={
+IntNum = Type3Class('IntNum', (a, ), methods={
     'abs': [a, a],
     'neg': [a, a],
 }, operators={}, inherited_classes=[NatNum])
@@ -447,7 +462,7 @@ instance_type_class(IntNum, f64, methods={
     'neg': stdtypes.f64_intnum_neg,
 })
 
-Integral = Type3Class('Eq', [a], methods={
+Integral = Type3Class('Eq', (a, ), methods={
 }, operators={
     '//': [a, a, a],
     '%': [a, a, a],
@@ -470,7 +485,7 @@ instance_type_class(Integral, i64, operators={
     '%': stdtypes.i64_integral_rem,
 })
 
-Fractional = Type3Class('Fractional', [a], methods={
+Fractional = Type3Class('Fractional', (a, ), methods={
     'ceil': [a, a],
     'floor': [a, a],
     'trunc': [a, a],
@@ -496,7 +511,7 @@ instance_type_class(Fractional, f64, methods={
     '/': stdtypes.f64_fractional_div,
 })
 
-Floating = Type3Class('Floating', [a], methods={
+Floating = Type3Class('Floating', (a, ), methods={
     'sqrt': [a, a],
 }, operators={}, inherited_classes=[Fractional])
 
@@ -509,7 +524,7 @@ instance_type_class(Floating, f64, methods={
     'sqrt': stdtypes.f64_floating_sqrt,
 })
 
-Sized_ = Type3Class('Sized', [a], methods={
+Sized_ = Type3Class('Sized', (a, ), methods={
     'len': [a, u32],
 }, operators={})  # FIXME: Once we get type class families, add [] here
 
@@ -517,7 +532,7 @@ instance_type_class(Sized_, bytes_, methods={
     'len': stdtypes.bytes_sized_len,
 })
 
-Extendable = Type3Class('Extendable', [a, b], methods={
+Extendable = Type3Class('Extendable', (a, b, ), methods={
     'extend': [a, b],
     'wrap': [b, a],
 }, operators={})
@@ -547,7 +562,7 @@ instance_type_class(Extendable, i32, i64, methods={
     'wrap': stdtypes.i32_i64_wrap,
 })
 
-Promotable = Type3Class('Promotable', [a, b], methods={
+Promotable = Type3Class('Promotable', (a, b, ), methods={
     'promote': [a, b],
     'demote': [b, a],
 }, operators={})
@@ -557,6 +572,16 @@ instance_type_class(Promotable, f32, f64, methods={
     'demote': stdtypes.f32_f64_demote,
 })
 
+Foldable = Type3Class('Foldable', (t, ), methods={
+    'sum': [t(a), a],
+}, operators={}, additional_context={
+    'sum': [Constraint_TypeClassInstanceExists(NatNum, (a, ))],
+})
+
+instance_type_class(Foldable, static_array, methods={
+    'sum': stdtypes.static_array_sum,
+})
+
 PRELUDE_TYPE_CLASSES = {
     'Eq': Eq,
     'Ord': Ord,
@@ -592,4 +617,5 @@ PRELUDE_METHODS = {
     **Sized_.methods,
     **Extendable.methods,
     **Promotable.methods,
+    **Foldable.methods,
 }
diff --git a/phasm/stdlib/types.py b/phasm/stdlib/types.py
index 5c7e46a..425dfa0 100644
--- a/phasm/stdlib/types.py
+++ b/phasm/stdlib/types.py
@@ -2,6 +2,8 @@
 stdlib: Standard types that are not wasm primitives
 """
 from phasm.stdlib import alloc
+from phasm.type3.routers import TypeVariableLookup
+from phasm.type3.types import IntType3, Type3
 from phasm.wasmgenerator import Generator, func_wrapper
 from phasm.wasmgenerator import VarType_i32 as i32
 from phasm.wasmgenerator import VarType_i64 as i64
@@ -387,444 +389,579 @@ def __u8_rotr__(g: Generator, x: i32, r: i32) -> i32:
 ## ###
 ## class Eq
 
-def u8_eq_equals(g: Generator) -> None:
+def u8_eq_equals(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.eq()
 
-def u32_eq_equals(g: Generator) -> None:
+def u32_eq_equals(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.eq()
 
-def u64_eq_equals(g: Generator) -> None:
+def u64_eq_equals(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i64.eq()
 
-def i8_eq_equals(g: Generator) -> None:
+def i8_eq_equals(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.eq()
 
-def i32_eq_equals(g: Generator) -> None:
+def i32_eq_equals(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.eq()
 
-def i64_eq_equals(g: Generator) -> None:
+def i64_eq_equals(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i64.eq()
 
-def f32_eq_equals(g: Generator) -> None:
+def f32_eq_equals(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f32.eq()
 
-def f64_eq_equals(g: Generator) -> None:
+def f64_eq_equals(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f64.eq()
 
-def u8_eq_not_equals(g: Generator) -> None:
+def u8_eq_not_equals(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.ne()
 
-def u32_eq_not_equals(g: Generator) -> None:
+def u32_eq_not_equals(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.ne()
 
-def u64_eq_not_equals(g: Generator) -> None:
+def u64_eq_not_equals(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i64.ne()
 
-def i8_eq_not_equals(g: Generator) -> None:
+def i8_eq_not_equals(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.ne()
 
-def i32_eq_not_equals(g: Generator) -> None:
+def i32_eq_not_equals(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.ne()
 
-def i64_eq_not_equals(g: Generator) -> None:
+def i64_eq_not_equals(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i64.ne()
 
-def f32_eq_not_equals(g: Generator) -> None:
+def f32_eq_not_equals(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f32.ne()
 
-def f64_eq_not_equals(g: Generator) -> None:
+def f64_eq_not_equals(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f64.ne()
 
 ## ###
 ## class Ord
 
-def u8_ord_min(g: Generator) -> None:
+def u8_ord_min(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('call $stdlib.types.__u32_ord_min__')
 
-def u32_ord_min(g: Generator) -> None:
+def u32_ord_min(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('call $stdlib.types.__u32_ord_min__')
 
-def u64_ord_min(g: Generator) -> None:
+def u64_ord_min(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('call $stdlib.types.__u64_ord_min__')
 
-def i8_ord_min(g: Generator) -> None:
+def i8_ord_min(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('call $stdlib.types.__i32_ord_min__')
 
-def i32_ord_min(g: Generator) -> None:
+def i32_ord_min(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('call $stdlib.types.__i32_ord_min__')
 
-def i64_ord_min(g: Generator) -> None:
+def i64_ord_min(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('call $stdlib.types.__i64_ord_min__')
 
-def f32_ord_min(g: Generator) -> None:
+def f32_ord_min(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f32.min()
 
-def f64_ord_min(g: Generator) -> None:
+def f64_ord_min(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f64.min()
 
-def u8_ord_max(g: Generator) -> None:
+def u8_ord_max(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('call $stdlib.types.__u32_ord_max__')
 
-def u32_ord_max(g: Generator) -> None:
+def u32_ord_max(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('call $stdlib.types.__u32_ord_max__')
 
-def u64_ord_max(g: Generator) -> None:
+def u64_ord_max(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('call $stdlib.types.__u64_ord_max__')
 
-def i8_ord_max(g: Generator) -> None:
+def i8_ord_max(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('call $stdlib.types.__i32_ord_max__')
 
-def i32_ord_max(g: Generator) -> None:
+def i32_ord_max(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('call $stdlib.types.__i32_ord_max__')
 
-def i64_ord_max(g: Generator) -> None:
+def i64_ord_max(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('call $stdlib.types.__i64_ord_max__')
 
-def f32_ord_max(g: Generator) -> None:
+def f32_ord_max(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f32.max()
 
-def f64_ord_max(g: Generator) -> None:
+def f64_ord_max(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f64.max()
 
 
-def u8_ord_less_than(g: Generator) -> None:
+def u8_ord_less_than(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.lt_u()
 
-def u32_ord_less_than(g: Generator) -> None:
+def u32_ord_less_than(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.lt_u()
 
-def u64_ord_less_than(g: Generator) -> None:
+def u64_ord_less_than(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i64.lt_u()
 
-def i8_ord_less_than(g: Generator) -> None:
+def i8_ord_less_than(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.lt_s()
 
-def i32_ord_less_than(g: Generator) -> None:
+def i32_ord_less_than(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.lt_s()
 
-def i64_ord_less_than(g: Generator) -> None:
+def i64_ord_less_than(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i64.lt_s()
 
-def f32_ord_less_than(g: Generator) -> None:
+def f32_ord_less_than(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f32.lt()
 
-def f64_ord_less_than(g: Generator) -> None:
+def f64_ord_less_than(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f64.lt()
 
-def u8_ord_less_than_or_equal(g: Generator) -> None:
+def u8_ord_less_than_or_equal(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.le_u()
 
-def u32_ord_less_than_or_equal(g: Generator) -> None:
+def u32_ord_less_than_or_equal(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.le_u()
 
-def u64_ord_less_than_or_equal(g: Generator) -> None:
+def u64_ord_less_than_or_equal(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i64.le_u()
 
-def i8_ord_less_than_or_equal(g: Generator) -> None:
+def i8_ord_less_than_or_equal(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.le_s()
 
-def i32_ord_less_than_or_equal(g: Generator) -> None:
+def i32_ord_less_than_or_equal(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.le_s()
 
-def i64_ord_less_than_or_equal(g: Generator) -> None:
+def i64_ord_less_than_or_equal(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i64.le_s()
 
-def f32_ord_less_than_or_equal(g: Generator) -> None:
+def f32_ord_less_than_or_equal(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f32.le()
 
-def f64_ord_less_than_or_equal(g: Generator) -> None:
+def f64_ord_less_than_or_equal(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f64.le()
 
-def u8_ord_greater_than(g: Generator) -> None:
+def u8_ord_greater_than(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.gt_u()
 
-def u32_ord_greater_than(g: Generator) -> None:
+def u32_ord_greater_than(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.gt_u()
 
-def u64_ord_greater_than(g: Generator) -> None:
+def u64_ord_greater_than(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i64.gt_u()
 
-def i8_ord_greater_than(g: Generator) -> None:
+def i8_ord_greater_than(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.gt_s()
 
-def i32_ord_greater_than(g: Generator) -> None:
+def i32_ord_greater_than(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.gt_s()
 
-def i64_ord_greater_than(g: Generator) -> None:
+def i64_ord_greater_than(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i64.gt_s()
 
-def f32_ord_greater_than(g: Generator) -> None:
+def f32_ord_greater_than(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f32.gt()
 
-def f64_ord_greater_than(g: Generator) -> None:
+def f64_ord_greater_than(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f64.gt()
 
-def u8_ord_greater_than_or_equal(g: Generator) -> None:
+def u8_ord_greater_than_or_equal(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.ge_u()
 
-def u32_ord_greater_than_or_equal(g: Generator) -> None:
+def u32_ord_greater_than_or_equal(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.ge_u()
 
-def u64_ord_greater_than_or_equal(g: Generator) -> None:
+def u64_ord_greater_than_or_equal(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i64.ge_u()
 
-def i8_ord_greater_than_or_equal(g: Generator) -> None:
+def i8_ord_greater_than_or_equal(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.ge_s()
 
-def i32_ord_greater_than_or_equal(g: Generator) -> None:
+def i32_ord_greater_than_or_equal(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.ge_s()
 
-def i64_ord_greater_than_or_equal(g: Generator) -> None:
+def i64_ord_greater_than_or_equal(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i64.ge_s()
 
-def f32_ord_greater_than_or_equal(g: Generator) -> None:
+def f32_ord_greater_than_or_equal(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f32.ge()
 
-def f64_ord_greater_than_or_equal(g: Generator) -> None:
+def f64_ord_greater_than_or_equal(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f64.ge()
 
 ## ###
 ## class Bits
 
-def u8_bits_logical_shift_left(g: Generator) -> None:
+def u8_bits_logical_shift_left(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.shl()
     g.i32.const(255)
     g.i32.and_()
 
-def u32_bits_logical_shift_left(g: Generator) -> None:
+def u32_bits_logical_shift_left(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.shl()
 
-def u64_bits_logical_shift_left(g: Generator) -> None:
+def u64_bits_logical_shift_left(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i64.extend_i32_u()
     g.i64.shl()
 
-def u8_bits_logical_shift_right(g: Generator) -> None:
+def u8_bits_logical_shift_right(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.shr_u()
 
-def u32_bits_logical_shift_right(g: Generator) -> None:
+def u32_bits_logical_shift_right(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.shr_u()
 
-def u64_bits_logical_shift_right(g: Generator) -> None:
+def u64_bits_logical_shift_right(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i64.extend_i32_u()
     g.i64.shr_u()
 
-def u8_bits_rotate_left(g: Generator) -> None:
+def u8_bits_rotate_left(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('call $stdlib.types.__u8_rotl__')
 
-def u32_bits_rotate_left(g: Generator) -> None:
+def u32_bits_rotate_left(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.rotl()
 
-def u64_bits_rotate_left(g: Generator) -> None:
+def u64_bits_rotate_left(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i64.extend_i32_u()
     g.i64.rotl()
 
-def u8_bits_rotate_right(g: Generator) -> None:
+def u8_bits_rotate_right(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('call $stdlib.types.__u8_rotr__')
 
-def u32_bits_rotate_right(g: Generator) -> None:
+def u32_bits_rotate_right(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.rotr()
 
-def u64_bits_rotate_right(g: Generator) -> None:
+def u64_bits_rotate_right(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i64.extend_i32_u()
     g.i64.rotr()
 
-def u8_bits_bitwise_and(g: Generator) -> None:
+def u8_bits_bitwise_and(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.and_()
 
-def u32_bits_bitwise_and(g: Generator) -> None:
+def u32_bits_bitwise_and(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.and_()
 
-def u64_bits_bitwise_and(g: Generator) -> None:
+def u64_bits_bitwise_and(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i64.and_()
 
-def u8_bits_bitwise_or(g: Generator) -> None:
+def u8_bits_bitwise_or(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.or_()
 
-def u32_bits_bitwise_or(g: Generator) -> None:
+def u32_bits_bitwise_or(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.or_()
 
-def u64_bits_bitwise_or(g: Generator) -> None:
+def u64_bits_bitwise_or(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i64.or_()
 
-def u8_bits_bitwise_xor(g: Generator) -> None:
+def u8_bits_bitwise_xor(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.xor()
 
-def u32_bits_bitwise_xor(g: Generator) -> None:
+def u32_bits_bitwise_xor(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.xor()
 
-def u64_bits_bitwise_xor(g: Generator) -> None:
+def u64_bits_bitwise_xor(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i64.xor()
 
 ## ###
 ## class Fractional
 
-def f32_fractional_ceil(g: Generator) -> None:
+def f32_fractional_ceil(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f32.ceil()
 
-def f64_fractional_ceil(g: Generator) -> None:
+def f64_fractional_ceil(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f64.ceil()
 
-def f32_fractional_floor(g: Generator) -> None:
+def f32_fractional_floor(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f32.floor()
 
-def f64_fractional_floor(g: Generator) -> None:
+def f64_fractional_floor(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f64.floor()
 
-def f32_fractional_trunc(g: Generator) -> None:
+def f32_fractional_trunc(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f32.trunc()
 
-def f64_fractional_trunc(g: Generator) -> None:
+def f64_fractional_trunc(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f64.trunc()
 
-def f32_fractional_nearest(g: Generator) -> None:
+def f32_fractional_nearest(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f32.nearest()
 
-def f64_fractional_nearest(g: Generator) -> None:
+def f64_fractional_nearest(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f64.nearest()
 
-def f32_fractional_div(g: Generator) -> None:
+def f32_fractional_div(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f32.div()
 
-def f64_fractional_div(g: Generator) -> None:
+def f64_fractional_div(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f64.div()
 
 ## ###
 ## class Floating
 
-def f32_floating_sqrt(g: Generator) -> None:
+def f32_floating_sqrt(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('f32.sqrt')
 
-def f64_floating_sqrt(g: Generator) -> None:
+def f64_floating_sqrt(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('f64.sqrt')
 
 ## ###
 ## class Integral
 
-def u32_integral_div(g: Generator) -> None:
+def u32_integral_div(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('i32.div_u')
 
-def u64_integral_div(g: Generator) -> None:
+def u64_integral_div(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('i64.div_u')
 
-def i32_integral_div(g: Generator) -> None:
+def i32_integral_div(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('i32.div_s')
 
-def i64_integral_div(g: Generator) -> None:
+def i64_integral_div(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('i64.div_s')
 
-def u32_integral_rem(g: Generator) -> None:
+def u32_integral_rem(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('i32.rem_u')
 
-def u64_integral_rem(g: Generator) -> None:
+def u64_integral_rem(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('i64.rem_u')
 
-def i32_integral_rem(g: Generator) -> None:
+def i32_integral_rem(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('i32.rem_s')
 
-def i64_integral_rem(g: Generator) -> None:
+def i64_integral_rem(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('i64.rem_s')
 
 ## ###
 ## class NatNum
 
-def u32_natnum_add(g: Generator) -> None:
+def u32_natnum_add(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('i32.add')
 
-def u64_natnum_add(g: Generator) -> None:
+def u64_natnum_add(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('i64.add')
 
-def i32_natnum_add(g: Generator) -> None:
+def i32_natnum_add(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('i32.add')
 
-def i64_natnum_add(g: Generator) -> None:
+def i64_natnum_add(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('i64.add')
 
-def f32_natnum_add(g: Generator) -> None:
+def f32_natnum_add(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('f32.add')
 
-def f64_natnum_add(g: Generator) -> None:
+def f64_natnum_add(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('f64.add')
 
-def u32_natnum_sub(g: Generator) -> None:
+def u32_natnum_sub(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('i32.sub')
 
-def u64_natnum_sub(g: Generator) -> None:
+def u64_natnum_sub(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('i64.sub')
 
-def i32_natnum_sub(g: Generator) -> None:
+def i32_natnum_sub(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('i32.sub')
 
-def i64_natnum_sub(g: Generator) -> None:
+def i64_natnum_sub(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('i64.sub')
 
-def f32_natnum_sub(g: Generator) -> None:
+def f32_natnum_sub(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('f32.sub')
 
-def f64_natnum_sub(g: Generator) -> None:
+def f64_natnum_sub(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('f64.sub')
 
-def u32_natnum_mul(g: Generator) -> None:
+def u32_natnum_mul(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('i32.mul')
 
-def u64_natnum_mul(g: Generator) -> None:
+def u64_natnum_mul(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('i64.mul')
 
-def i32_natnum_mul(g: Generator) -> None:
+def i32_natnum_mul(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('i32.mul')
 
-def i64_natnum_mul(g: Generator) -> None:
+def i64_natnum_mul(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('i64.mul')
 
-def f32_natnum_mul(g: Generator) -> None:
+def f32_natnum_mul(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('f32.mul')
 
-def f64_natnum_mul(g: Generator) -> None:
+def f64_natnum_mul(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('f64.mul')
 
-def u32_natnum_arithmic_shift_left(g: Generator) -> None:
+def u32_natnum_arithmic_shift_left(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.shl()
 
-def u64_natnum_arithmic_shift_left(g: Generator) -> None:
+def u64_natnum_arithmic_shift_left(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i64.extend_i32_u()
     g.i64.shl()
 
-def i32_natnum_arithmic_shift_left(g: Generator) -> None:
+def i32_natnum_arithmic_shift_left(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.shl()
 
-def i64_natnum_arithmic_shift_left(g: Generator) -> None:
+def i64_natnum_arithmic_shift_left(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i64.extend_i32_u()
     g.i64.shl()
 
-def f32_natnum_arithmic_shift_left(g: Generator) -> None:
+def f32_natnum_arithmic_shift_left(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('call $stdlib.types.__u32_pow2__')
     g.f32.convert_i32_u()
     g.f32.mul()
 
-def f64_natnum_arithmic_shift_left(g: Generator) -> None:
+def f64_natnum_arithmic_shift_left(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('call $stdlib.types.__u32_pow2__')
     g.f64.convert_i32_u()
     g.f64.mul()
 
-def u32_natnum_arithmic_shift_right(g: Generator) -> None:
+def u32_natnum_arithmic_shift_right(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.shr_u()
 
-def u64_natnum_arithmic_shift_right(g: Generator) -> None:
+def u64_natnum_arithmic_shift_right(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i64.extend_i32_u()
     g.i64.shr_u()
 
-def i32_natnum_arithmic_shift_right(g: Generator) -> None:
+def i32_natnum_arithmic_shift_right(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.shr_s()
 
-def i64_natnum_arithmic_shift_right(g: Generator) -> None:
+def i64_natnum_arithmic_shift_right(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i64.extend_i32_u()
     g.i64.shr_s()
 
-def f32_natnum_arithmic_shift_right(g: Generator) -> None:
+def f32_natnum_arithmic_shift_right(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('call $stdlib.types.__u32_pow2__')
     g.f32.convert_i32_u()
     g.f32.div()
 
-def f64_natnum_arithmic_shift_right(g: Generator) -> None:
+def f64_natnum_arithmic_shift_right(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('call $stdlib.types.__u32_pow2__')
     g.f64.convert_i32_u()
     g.f64.div()
@@ -832,91 +969,219 @@ def f64_natnum_arithmic_shift_right(g: Generator) -> None:
 ## ###
 ## class IntNum
 
-def i32_intnum_abs(g: Generator) -> None:
+def i32_intnum_abs(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('call $stdlib.types.__i32_intnum_abs__')
 
-def i64_intnum_abs(g: Generator) -> None:
+def i64_intnum_abs(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.add_statement('call $stdlib.types.__i64_intnum_abs__')
 
-def f32_intnum_abs(g: Generator) -> None:
+def f32_intnum_abs(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f32.abs()
 
-def f64_intnum_abs(g: Generator) -> None:
+def f64_intnum_abs(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f64.abs()
 
-def i32_intnum_neg(g: Generator) -> None:
+def i32_intnum_neg(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.const(-1)
     g.i32.mul()
 
-def i64_intnum_neg(g: Generator) -> None:
+def i64_intnum_neg(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i64.const(-1)
     g.i64.mul()
 
-def f32_intnum_neg(g: Generator) -> None:
+def f32_intnum_neg(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f32.neg()
 
-def f64_intnum_neg(g: Generator) -> None:
+def f64_intnum_neg(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f64.neg()
 
 ## ###
 ## Class Sized
 
-def bytes_sized_len(g: Generator) -> None:
+def bytes_sized_len(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     # The length is stored in the first 4 bytes
     g.i32.load()
 
 ## ###
 ## Extendable
 
-def u8_u32_extend(g: Generator) -> None:
+def u8_u32_extend(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     # No-op
     # u8 is already stored as u32
     pass
 
-def u8_u64_extend(g: Generator) -> None:
+def u8_u64_extend(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i64.extend_i32_u()
 
-def u32_u64_extend(g: Generator) -> None:
+def u32_u64_extend(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i64.extend_i32_u()
 
-def i8_i32_extend(g: Generator) -> None:
+def i8_i32_extend(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     # No-op
     # i8 is already stored as i32
     pass
 
-def i8_i64_extend(g: Generator) -> None:
+def i8_i64_extend(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i64.extend_i32_s()
 
-def i32_i64_extend(g: Generator) -> None:
+def i32_i64_extend(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i64.extend_i32_s()
 
-def u8_u32_wrap(g: Generator) -> None:
+def u8_u32_wrap(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.const(0xFF)
     g.i32.and_()
 
-def u8_u64_wrap(g: Generator) -> None:
+def u8_u64_wrap(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.wrap_i64()
     g.i32.const(0xFF)
     g.i32.and_()
 
-def u32_u64_wrap(g: Generator) -> None:
+def u32_u64_wrap(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.wrap_i64()
 
-def i8_i32_wrap(g: Generator) -> None:
+def i8_i32_wrap(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.const(0xFF)
     g.i32.and_()
 
-def i8_i64_wrap(g: Generator) -> None:
+def i8_i64_wrap(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.wrap_i64()
 
-def i32_i64_wrap(g: Generator) -> None:
+def i32_i64_wrap(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.i32.wrap_i64()
 
 ## ###
 ## Promotable
 
-def f32_f64_promote(g: Generator) -> None:
+def f32_f64_promote(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f64.promote_f32()
 
-def f32_f64_demote(g: Generator) -> None:
+def f32_f64_demote(g: Generator, tv_map: TypeVariableLookup) -> None:
+    del tv_map
     g.f32.demote_f64()
+
+def static_array_sum(g: Generator, tv_map: TypeVariableLookup) -> None:
+    assert len(tv_map) == 1
+    sa_type, sa_len = next(iter(tv_map.values()))
+    assert isinstance(sa_type, Type3)
+    assert isinstance(sa_len, IntType3)
+
+    if sa_len.value < 1:
+        raise NotImplementedError('Default value in case sum is empty')
+
+    # FIXME: We should probably use LOAD_STORE_TYPE_MAP for this?
+    mtyp_map = {
+        'u32': 'i32',
+        'u64': 'i64',
+        'i32': 'i32',
+        'i64': 'i64',
+        'f32': 'f32',
+        'f64': 'f64',
+    }
+
+    # FIXME: We should probably use calc_alloc_size for this?
+    type_var_size_map = {
+        'u32': 4,
+        'u64': 8,
+        'i32': 4,
+        'i64': 8,
+        'f32': 4,
+        'f64': 8,
+    }
+
+    type_var_add_generator = {
+        'u32': u32_natnum_add,
+        'u64': u64_natnum_add,
+        'i32': i32_natnum_add,
+        'i64': i64_natnum_add,
+        'f32': f32_natnum_add,
+        'f64': f64_natnum_add,
+    }
+
+    # By default, constructed types are passed as pointers
+    # FIXME: We don't know what add function to call
+    sa_type_mtyp = mtyp_map.get(sa_type.name, 'i32')
+    sa_type_alloc_size = type_var_size_map.get(sa_type.name, 4)
+    sa_type_add_gen = type_var_add_generator[sa_type.name]
+
+    # Definitions
+    sum_adr = g.temp_var(i32('sum_adr'))
+    sum_stop = g.temp_var(i32('sum_stop'))
+
+    # Stack before: [adr]
+    # Stack after:  [sum]
+
+    # adr = {address of what's currently on stack}
+    # Stack: [adr] -> []
+    g.nop(comment=f'Start sum for {sa_type.name}[{sa_len.value}]')
+    g.local.set(sum_adr)
+
+    # stop = adr + ar_len * sa_type_alloc_size
+    # Stack: []
+    g.nop(comment='Calculate address at which to stop looping')
+    g.local.get(sum_adr)
+    g.i32.const(sa_len.value * sa_type_alloc_size)
+    g.i32.add()
+    g.local.set(sum_stop)
+
+    # sum = *adr
+    # Stack: [] -> [sum]
+    g.nop(comment='Get the first array value as starting point')
+    g.local.get(sum_adr)
+    g.add_statement(f'{sa_type_mtyp}.load')
+
+    # Since we did the first one, increase adr
+    # adr = adr + sa_type_alloc_size
+    # Stack: [sum] -> [sum]
+    g.local.get(sum_adr)
+    g.i32.const(sa_type_alloc_size)
+    g.i32.add()
+    g.local.set(sum_adr)
+
+    if sa_len.value > 1:
+        with g.loop(params=[sa_type_mtyp], result=sa_type_mtyp):
+            # sum = sum + *adr
+            # Stack: [sum] -> [sum + *adr]
+            g.nop(comment='Add array value')
+            g.local.get(sum_adr)
+            g.add_statement(f'{sa_type_mtyp}.load')
+            sa_type_add_gen(g, {})
+
+            # adr = adr + sa_type_alloc_size
+            # Stack: [sum] -> [sum]
+            g.nop(comment='Calculate address of the next value')
+            g.local.get(sum_adr)
+            g.i32.const(sa_type_alloc_size)
+            g.i32.add()
+            g.local.tee(sum_adr)
+
+            # loop if adr < stop
+            g.nop(comment='Check if address exceeds array bounds')
+            g.local.get(sum_stop)
+            g.i32.lt_u()
+            g.br_if(0)
+    # else: sum x[1] === x => so we don't need to loop
+
+    g.nop(comment=f'Completed sum for {sa_type.name}[{sa_len.value}]')
+    # End result: [sum]
diff --git a/phasm/type3/constraints.py b/phasm/type3/constraints.py
index efa2181..94a17de 100644
--- a/phasm/type3/constraints.py
+++ b/phasm/type3/constraints.py
@@ -3,7 +3,7 @@ This module contains possible constraints generated based on the AST
 
 These need to be resolved before the program can be compiled.
 """
-from typing import Dict, Iterable, List, Optional, Tuple, Union
+from typing import Any, Dict, Iterable, List, Optional, Tuple, Union
 
 from .. import ourlang, prelude
 from . import placeholders, typeclasses, types
@@ -50,7 +50,7 @@ class Context:
     __slots__ = ('type_class_instances_existing', )
 
     # Constraint_TypeClassInstanceExists
-    type_class_instances_existing: set[tuple[typeclasses.Type3Class, tuple[types.Type3, ...]]]
+    type_class_instances_existing: set[tuple[typeclasses.Type3Class, tuple[Union[types.Type3, types.TypeConstructor_Base[Any], types.TypeConstructor_Struct], ...]]]
 
     def __init__(self) -> None:
         self.type_class_instances_existing = set()
@@ -158,6 +158,46 @@ class SameTypeConstraint(ConstraintBase):
 
         return f'SameTypeConstraint({args}, comment={repr(self.comment)})'
 
+class SameTypeArgumentConstraint(ConstraintBase):
+    __slots__ = ('tc_var', 'arg_var', )
+
+    tc_var: PlaceholderForType
+    arg_var: PlaceholderForType
+
+    def __init__(self, tc_var: PlaceholderForType, arg_var: PlaceholderForType, *, comment: str) -> None:
+        super().__init__(comment=comment)
+
+        self.tc_var = tc_var
+        self.arg_var = arg_var
+
+    def check(self) -> CheckResult:
+        if self.tc_var.resolve_as is None or self.arg_var.resolve_as is None:
+            return RequireTypeSubstitutes()
+
+        tc_typ = self.tc_var.resolve_as
+        arg_typ = self.arg_var.resolve_as
+
+        if isinstance(tc_typ.application, types.TypeApplication_Nullary):
+            return Error(f'{tc_typ:s} must be a constructed type instead')
+
+        if isinstance(tc_typ.application, types.TypeApplication_TypeStar):
+            # Sure, it's a constructed type. But it's like a struct,
+            # though without the way to implement type classes
+            # Presumably, doing a naked `foo :: t a -> a`
+            # doesn't work since you don't have any info on t
+            # So we can let the MustImplementTypeClassConstraint handle it.
+            return None
+
+        # FIXME: This feels sketchy. Shouldn't the type variable
+        # have the exact same number as arguments?
+        if isinstance(tc_typ.application, types.TypeApplication_TypeInt):
+            if tc_typ.application.arguments[0] == arg_typ:
+                return None
+
+            return Error(f'{tc_typ.application.arguments[0]:s} must be {arg_typ:s} instead')
+
+        raise NotImplementedError(tc_typ, arg_typ)
+
 class TupleMatchConstraint(ConstraintBase):
     __slots__ = ('exp_type', 'args', )
 
@@ -229,7 +269,7 @@ class MustImplementTypeClassConstraint(ConstraintBase):
         self.types = types
 
     def check(self) -> CheckResult:
-        typ_list = []
+        typ_list: list[types.Type3 | types.TypeConstructor_Base[Any] | types.TypeConstructor_Struct] = []
         for typ in self.types:
             if isinstance(typ, placeholders.PlaceholderForType) and typ.resolve_as is not None:
                 typ = typ.resolve_as
@@ -237,7 +277,15 @@ class MustImplementTypeClassConstraint(ConstraintBase):
             if isinstance(typ, placeholders.PlaceholderForType):
                 return RequireTypeSubstitutes()
 
-            typ_list.append(typ)
+            if isinstance(typ.application, (types.TypeApplication_Nullary, types.TypeApplication_Struct, )):
+                typ_list.append(typ)
+                continue
+
+            if isinstance(typ.application, (types.TypeApplication_TypeInt, types.TypeApplication_TypeStar)):
+                typ_list.append(typ.application.constructor)
+                continue
+
+            raise NotImplementedError(typ, typ.application)
 
         assert len(typ_list) == len(self.types)
 
diff --git a/phasm/type3/constraintsgenerator.py b/phasm/type3/constraintsgenerator.py
index c10ce86..2b98966 100644
--- a/phasm/type3/constraintsgenerator.py
+++ b/phasm/type3/constraintsgenerator.py
@@ -16,6 +16,7 @@ from .constraints import (
     Context,
     LiteralFitsConstraint,
     MustImplementTypeClassConstraint,
+    SameTypeArgumentConstraint,
     SameTypeConstraint,
     TupleMatchConstraint,
 )
@@ -39,6 +40,116 @@ def constant(ctx: Context, inp: ourlang.Constant, phft: placeholders.Placeholder
 
     raise NotImplementedError(constant, inp)
 
+def expression_binary_op(ctx: Context, inp: ourlang.BinaryOp, phft: PlaceholderForType) -> ConstraintGenerator:
+    return _expression_function_call(
+        ctx,
+        f'({inp.operator.name})',
+        inp.operator.signature,
+        [inp.left, inp.right],
+        inp,
+        phft,
+    )
+
+def expression_function_call(ctx: Context, inp: ourlang.FunctionCall, phft: PlaceholderForType) -> ConstraintGenerator:
+    return _expression_function_call(
+            ctx,
+            inp.function.name,
+            inp.function.signature,
+            inp.arguments,
+            inp,
+            phft,
+        )
+
+def _expression_function_call(
+        ctx: Context,
+        func_name: str,
+        signature: functions.FunctionSignature,
+        arguments: list[ourlang.Expression],
+        return_expr: ourlang.Expression,
+        return_phft: PlaceholderForType,
+    ) -> ConstraintGenerator:
+    """
+    Generates all type-level constraints for a function call.
+
+    A Binary operator functions pretty much the same as a function call
+    with two arguments - it's only a syntactic difference.
+    """
+    # First create placeholders for all arguments, and generate their constraints
+    arg_placeholders = {
+        arg_expr: PlaceholderForType([arg_expr])
+        for arg_expr in arguments
+    }
+    arg_placeholders[return_expr] = return_phft
+
+    for call_arg in arguments:
+        yield from expression(ctx, call_arg, arg_placeholders[call_arg])
+
+    # Then generate placeholders the function signature
+    # and apply constraints that the function requires
+    # Skip any fully reference types
+    # Making this a map ensures that if a function signature has
+    # the same type on multiple arguments, we only get one
+    # placeholder here. These don't need to update anything once
+    # subsituted - that's done by arg_placeholders.
+    type_var_map = {
+        x: placeholders.PlaceholderForType([])
+        for x in signature.args
+        if isinstance(x, functions.TypeVariable)
+    }
+
+    for constraint in signature.context.constraints:
+        if isinstance(constraint, functions.Constraint_TypeClassInstanceExists):
+            yield MustImplementTypeClassConstraint(
+                ctx,
+                constraint.type_class3,
+                [type_var_map[x] for x in constraint.types],
+            )
+            continue
+
+        raise NotImplementedError(constraint)
+
+    # If some of the function arguments are type constructors,
+    # we need to deal with those separately.
+    # That is, given `foo :: t a -> a` we need to ensure
+    # that both a's are the same.
+    for sig_arg in signature.args:
+        if isinstance(sig_arg, type3types.Type3):
+            # Not a type variable at all
+            continue
+
+        if sig_arg.application.constructor is None:
+            # Not a type variable for a type constructor
+            continue
+
+        if not isinstance(sig_arg.application, functions.TypeVariableApplication_Unary):
+            raise NotImplementedError(sig_arg.application)
+
+        assert sig_arg.application.arguments in type_var_map  # When does this happen?
+
+        yield SameTypeArgumentConstraint(
+            type_var_map[sig_arg],
+            type_var_map[sig_arg.application.arguments],
+            comment=f'Ensure `{sig_arg.application.arguments.name}` matches in {signature}',
+        )
+
+    # Lastly, tie the signature and expression together
+    for arg_no, (sig_part, arg_expr) in enumerate(zip(signature.args, arguments + [return_expr], strict=True)):
+        if arg_no == len(arguments):
+            comment = f'The type of a function call to {func_name} is the same as the type that the function returns'
+        else:
+            comment = f'The type of the value passed to argument {arg_no} of function {func_name} should match the type of that argument'
+
+        if isinstance(sig_part, functions.TypeVariable):
+            yield SameTypeConstraint(type_var_map[sig_part], arg_placeholders[arg_expr], comment=comment)
+            continue
+
+        if isinstance(sig_part, type3types.Type3):
+            yield SameTypeConstraint(sig_part, arg_placeholders[arg_expr], comment=comment)
+            continue
+
+        raise NotImplementedError(sig_part)
+    return
+
 def expression(ctx: Context, inp: ourlang.Expression, phft: placeholders.PlaceholderForType) -> ConstraintGenerator:
     if isinstance(inp, ourlang.Constant):
         yield from constant(ctx, inp, phft)
@@ -49,53 +160,12 @@ def expression(ctx: Context, inp: ourlang.Expression, phft: placeholders.Placeho
             comment=f'typeOf("{inp.variable.name}") == typeOf({inp.variable.name})')
         return
 
-    if isinstance(inp, ourlang.BinaryOp) or isinstance(inp, ourlang.FunctionCall):
-        signature = inp.operator.signature if isinstance(inp, ourlang.BinaryOp) else inp.function.signature
-        arguments = [inp.left, inp.right] if isinstance(inp, ourlang.BinaryOp) else inp.arguments
+    if isinstance(inp, ourlang.BinaryOp):
+        yield from expression_binary_op(ctx, inp, phft)
+        return
 
-        func_name = f'({inp.operator.name})' if isinstance(inp, ourlang.BinaryOp) else inp.function.name
-
-        type_var_map = {
-            x: placeholders.PlaceholderForType([])
-            for x in signature.args
-            if isinstance(x, functions.TypeVariable)
-        }
-
-        arg_placeholders = {
-            arg_expr: PlaceholderForType([arg_expr])
-            for arg_expr in arguments
-        }
-        arg_placeholders[inp] = phft
-
-        for arg_expr in arguments:
-            yield from expression(ctx, arg_expr, arg_placeholders[arg_expr])
-
-        for constraint in signature.context.constraints:
-            if isinstance(constraint, functions.Constraint_TypeClassInstanceExists):
-                yield MustImplementTypeClassConstraint(
-                    ctx,
-                    constraint.type_class3,
-                    [type_var_map[x] for x in constraint.types],
-                )
-                continue
-
-            raise NotImplementedError(constraint)
-
-        for arg_no, (sig_part, arg_expr) in enumerate(zip(signature.args, arguments + [inp], strict=True)):
-            if arg_no == len(arguments):
-                comment = f'The type of a function call to {func_name} is the same as the type that the function returns'
-            else:
-                comment = f'The type of the value passed to argument {arg_no} of function {func_name} should match the type of that argument'
-
-            if isinstance(sig_part, functions.TypeVariable):
-                yield SameTypeConstraint(type_var_map[sig_part], arg_placeholders[arg_expr], comment=comment)
-                continue
-
-            if isinstance(sig_part, type3types.Type3):
-                yield SameTypeConstraint(sig_part, arg_placeholders[arg_expr], comment=comment)
-                continue
-
-            raise NotImplementedError(sig_part)
+    if isinstance(inp, ourlang.FunctionCall):
+        yield from expression_function_call(ctx, inp, phft)
         return
 
     if isinstance(inp, ourlang.TupleInstantiation):
diff --git a/phasm/type3/functions.py b/phasm/type3/functions.py
index 4d924a5..1b91948 100644
--- a/phasm/type3/functions.py
+++ b/phasm/type3/functions.py
@@ -1,10 +1,36 @@
-from typing import TYPE_CHECKING, Any, Iterable, List, Union
+from typing import TYPE_CHECKING, Any, Hashable, Iterable, List, Union
 
 if TYPE_CHECKING:
     from .typeclasses import Type3Class
     from .types import Type3
 
 
+class TypeVariableApplication_Base[T: Hashable, S: Hashable]:
+    """
+    Records the constructor and arguments used to create this type.
+
+    Nullary types, or types of kind *, have both arguments set to None.
+    """
+    constructor: T
+    arguments: S
+
+    def __init__(self, constructor: T, arguments: S) -> None:
+        self.constructor = constructor
+        self.arguments = arguments
+
+    def __hash__(self) -> int:
+        return hash((self.constructor, self.arguments, ))
+
+    def __eq__(self, other: Any) -> bool:
+        if not isinstance(other, TypeVariableApplication_Base):
+            raise NotImplementedError
+
+        return (self.constructor == other.constructor  # type: ignore[no-any-return]
+            and self.arguments == other.arguments)
+
+    def __repr__(self) -> str:
+        return f'{self.__class__.__name__}({self.constructor!r}, {self.arguments!r})'
+
 class TypeVariable:
     """
     Types variable are used in function definition.
@@ -14,25 +40,77 @@ class TypeVariable:
     during type checking. These type variables are used solely in the
     function's definition
     """
-    __slots__ = ('letter', )
+    __slots__ = ('name', 'application', )
 
-    letter: str
+    name: str
+    application: TypeVariableApplication_Base[Any, Any]
 
-    def __init__(self, letter: str) -> None:
-        assert len(letter) == 1, f'{letter} is not a valid type variable'
-        self.letter = letter
+    def __init__(self, name: str, application: TypeVariableApplication_Base[Any, Any]) -> None:
+        self.name = name
+        self.application = application
 
     def __hash__(self) -> int:
-        return hash(self.letter)
+        return hash((self.name, self.application, ))
 
     def __eq__(self, other: Any) -> bool:
         if not isinstance(other, TypeVariable):
             raise NotImplementedError
 
-        return self.letter == other.letter
+        return (self.name == other.name
+            and self.application == other.application)
 
     def __repr__(self) -> str:
-        return f'TypeVariable({repr(self.letter)})'
+        return f'TypeVariable({repr(self.name)})'
+
+class TypeVariableApplication_Nullary(TypeVariableApplication_Base[None, None]):
+    """
+    For the type for this function argument it's not relevant if it was constructed.
+    """
+
+class TypeConstructorVariable:
+    """
+    Types constructor variable are used in function definition.
+
+    They are a lot like TypeVariable, except that they represent a
+    type constructor rather than a type directly.
+
+    For now, we only have type constructor variables for kind
+    * -> *.
+    """
+    __slots__ = ('name', )
+
+    name: str
+
+    def __init__(self, name: str) -> None:
+        self.name = name
+
+    def __hash__(self) -> int:
+        return hash((self.name, ))
+
+    def __eq__(self, other: Any) -> bool:
+        if other is None:
+            return False
+
+        if not isinstance(other, TypeConstructorVariable):
+            raise NotImplementedError
+
+        return (self.name == other.name)
+
+    def __call__(self, tvar: TypeVariable) -> 'TypeVariable':
+        return TypeVariable(
+            self.name + ' ' + tvar.name,
+            TypeVariableApplication_Unary(self, tvar)
+        )
+
+    def __repr__(self) -> str:
+        return f'TypeConstructorVariable({self.name!r})'
+
+class TypeVariableApplication_Unary(TypeVariableApplication_Base[TypeConstructorVariable, TypeVariable]):
+    """
+    The type for this function argument should be constructed from a type constructor.
+
+    And we need to know what construtor that was, since that's the one we support.
+    """
 
 class ConstraintBase:
     __slots__ = ()
@@ -52,7 +130,7 @@ class Constraint_TypeClassInstanceExists(ConstraintBase):
         assert len(self.type_class3.args) == len(self.types)
 
     def __str__(self) -> str:
-        return self.type_class3.name + ' ' + ' '.join(x.letter for x in self.types)
+        return self.type_class3.name + ' ' + ' '.join(x.name for x in self.types)
 
     def __repr__(self) -> str:
         return f'Constraint_TypeClassInstanceExists({self.type_class3.name}, {self.types!r})'
@@ -62,13 +140,11 @@ class TypeVariableContext:
 
     constraints: list[ConstraintBase]
 
-    def __init__(self) -> None:
-        self.constraints = []
+    def __init__(self, constraints: Iterable[ConstraintBase] = ()) -> None:
+        self.constraints = list(constraints)
 
     def __copy__(self) -> 'TypeVariableContext':
-        result = TypeVariableContext()
-        result.constraints.extend(self.constraints)
-        return result
+        return TypeVariableContext(self.constraints)
 
     def __str__(self) -> str:
         if not self.constraints:
@@ -90,7 +166,7 @@ class FunctionSignature:
         self.args = list(args)
 
     def __str__(self) -> str:
-        return str(self.context) + ' -> '.join(x.letter if isinstance(x, TypeVariable) else x.name for x in self.args)
+        return str(self.context) + ' -> '.join(x.name for x in self.args)
 
     def __repr__(self) -> str:
         return f'FunctionSignature({self.context!r}, {self.args!r})'
diff --git a/phasm/type3/routers.py b/phasm/type3/routers.py
index d575bb8..c592dac 100644
--- a/phasm/type3/routers.py
+++ b/phasm/type3/routers.py
@@ -1,9 +1,13 @@
-from typing import Any, Callable, TypeVar
+from typing import Any, Callable
 
-from .functions import FunctionSignature, TypeVariable
-from .types import Type3, TypeConstructor_Base
+from .functions import (
+    TypeConstructorVariable,
+    TypeVariable,
+    TypeVariableApplication_Unary,
+)
+from .typeclasses import Type3ClassArgs
+from .types import KindArgument, Type3, TypeApplication_TypeInt, TypeConstructor_Base
 
-T = TypeVar('T')
 
 class NoRouteForTypeException(Exception):
     pass
@@ -36,7 +40,7 @@ class TypeApplicationRouter[S, R]:
         """
         self.by_type[typ] = helper
 
-    def add(self, constructor: TypeConstructor_Base[T], helper: Callable[[S, T], R]) -> None:
+    def add[T](self, constructor: TypeConstructor_Base[T], helper: Callable[[S, T], R]) -> None:
         self.by_constructor[constructor] = helper
 
     def __call__(self, arg0: S, typ: Type3) -> R:
@@ -50,39 +54,66 @@ class TypeApplicationRouter[S, R]:
 
         raise NoRouteForTypeException(arg0, typ)
 
-class FunctionSignatureRouter[S, R]:
+TypeVariableLookup = dict[TypeVariable, tuple[KindArgument, ...]]
+
+class TypeClassArgsRouter[S, R]:
     """
-    Helper class to find a method based on a function signature
+    Helper class to find a method based on a type class argument list
     """
-    __slots__ = ('signature', 'data', )
+    __slots__ = ('args', 'data', )
 
-    signature: FunctionSignature
+    args: Type3ClassArgs
 
-    data: dict[tuple[Type3, ...], Callable[[S], R]]
+    data: dict[tuple[Type3 | TypeConstructor_Base[Any], ...], Callable[[S, TypeVariableLookup], R]]
 
-    def __init__(self, signature: FunctionSignature) -> None:
-        self.signature = signature
+    def __init__(self, args: Type3ClassArgs) -> None:
+        self.args = args
         self.data = {}
 
-    def add(self, tv_map: dict[TypeVariable, Type3], helper: Callable[[S], R]) -> None:
-        key = tuple(
-            tv_map[x]
-            for x in self.signature.args
-            if isinstance(x, TypeVariable)
-        )
-        # assert len(key) == len(tv_map), (key, tv_map)
+    def add(
+            self,
+            tv_map: dict[TypeVariable, Type3],
+            tc_map: dict[TypeConstructorVariable, TypeConstructor_Base[Any]],
+            helper: Callable[[S, TypeVariableLookup], R],
+        ) -> None:
 
-        self.data[key] = helper
+        key: list[Type3 | TypeConstructor_Base[Any]] = []
+
+        for tc_arg in self.args:
+            if isinstance(tc_arg, TypeVariable):
+                key.append(tv_map[tc_arg])
+            else:
+                key.append(tc_map[tc_arg])
+
+        self.data[tuple(key)] = helper
 
     def __call__(self, arg0: S, tv_map: dict[TypeVariable, Type3]) -> R:
-        key = tuple(
-            tv_map[x]
-            for x in self.signature.args
-            if isinstance(x, TypeVariable)
-        )
+        key: list[Type3 | TypeConstructor_Base[Any]] = []
+        arguments: TypeVariableLookup = {}
 
-        t_helper = self.data.get(key)
+        for tc_arg in self.args:
+            if isinstance(tc_arg, TypeVariable):
+                key.append(tv_map[tc_arg])
+                continue
+
+            for tvar, typ in tv_map.items():
+                tvar_constructor = tvar.application.constructor
+                if tvar_constructor != tc_arg:
+                    continue
+
+                key.append(typ.application.constructor)
+
+                if isinstance(tvar.application, TypeVariableApplication_Unary):
+                    # FIXME: This feels sketchy. Shouldn't the type variable
+                    # have the exact same number as arguments?
+                    if isinstance(typ.application, TypeApplication_TypeInt):
+                        arguments[tvar.application.arguments] = typ.application.arguments
+                        continue
+
+                raise NotImplementedError(tvar.application, typ.application)
+
+        t_helper = self.data.get(tuple(key))
         if t_helper is not None:
-            return t_helper(arg0)
+            return t_helper(arg0, arguments)
 
         raise NoRouteForTypeException(arg0, tv_map)
diff --git a/phasm/type3/typeclasses.py b/phasm/type3/typeclasses.py
index 4b09f66..83d87be 100644
--- a/phasm/type3/typeclasses.py
+++ b/phasm/type3/typeclasses.py
@@ -2,7 +2,9 @@ from typing import Dict, Iterable, List, Mapping, Optional, Union
 
 from .functions import (
     Constraint_TypeClassInstanceExists,
+    ConstraintBase,
     FunctionSignature,
+    TypeConstructorVariable,
     TypeVariable,
     TypeVariableContext,
 )
@@ -25,11 +27,13 @@ class Type3ClassMethod:
     def __repr__(self) -> str:
         return f'Type3ClassMethod({repr(self.name)}, {repr(self.signature)})'
 
+Type3ClassArgs = tuple[TypeVariable] | tuple[TypeVariable, TypeVariable] | tuple[TypeConstructorVariable]
+
 class Type3Class:
     __slots__ = ('name', 'args', 'methods', 'operators', 'inherited_classes', )
 
     name: str
-    args: List[TypeVariable]
+    args: Type3ClassArgs
     methods: Dict[str, Type3ClassMethod]
     operators: Dict[str, Type3ClassMethod]
     inherited_classes: List['Type3Class']
@@ -37,26 +41,60 @@ class Type3Class:
     def __init__(
             self,
             name: str,
-            args: Iterable[TypeVariable],
+            args: Type3ClassArgs,
             methods: Mapping[str, Iterable[Union[Type3, TypeVariable]]],
             operators: Mapping[str, Iterable[Union[Type3, TypeVariable]]],
             inherited_classes: Optional[List['Type3Class']] = None,
+            additional_context: Optional[Mapping[str, Iterable[ConstraintBase]]] = None,
         ) -> None:
         self.name = name
-        self.args = list(args)
-
-        context = TypeVariableContext()
-        context.constraints.append(Constraint_TypeClassInstanceExists(self, args))
+        self.args = args
 
         self.methods = {
-            k: Type3ClassMethod(k, FunctionSignature(context, v))
+            k: Type3ClassMethod(k, _create_signature(v, self))
             for k, v in methods.items()
         }
         self.operators = {
-            k: Type3ClassMethod(k, FunctionSignature(context, v))
+            k: Type3ClassMethod(k, _create_signature(v, self))
             for k, v in operators.items()
         }
         self.inherited_classes = inherited_classes or []
 
+        if additional_context:
+            for func_name, constraint_list in additional_context.items():
+                func = self.methods.get(func_name) or self.operators.get(func_name)
+                assert func is not None  # type hint
+
+                func.signature.context.constraints.extend(constraint_list)
+
     def __repr__(self) -> str:
         return self.name
+
+def _create_signature(
+        method_arg_list: Iterable[Type3 | TypeVariable],
+        type_class3: Type3Class,
+    ) -> FunctionSignature:
+    context = TypeVariableContext()
+    if not isinstance(type_class3.args[0], TypeConstructorVariable):
+        context.constraints.append(Constraint_TypeClassInstanceExists(type_class3, type_class3.args))
+
+    signature_args: list[Type3 | TypeVariable] = []
+    for method_arg in method_arg_list:
+        if isinstance(method_arg, Type3):
+            signature_args.append(method_arg)
+            continue
+
+        if isinstance(method_arg, TypeVariable):
+            type_constructor = method_arg.application.constructor
+            if type_constructor is None:
+                signature_args.append(method_arg)
+                continue
+
+            if (type_constructor, ) == type_class3.args:
+                context.constraints.append(Constraint_TypeClassInstanceExists(type_class3, [method_arg]))
+                signature_args.append(method_arg)
+                continue
+
+        raise NotImplementedError(method_arg)
+
+    return FunctionSignature(context, signature_args)
diff --git a/phasm/type3/types.py b/phasm/type3/types.py
index 5a971cf..7a1b835 100644
--- a/phasm/type3/types.py
+++ b/phasm/type3/types.py
@@ -29,6 +29,16 @@ class TypeApplication_Base[T: Hashable, S: Hashable]:
         self.constructor = constructor
         self.arguments = arguments
 
+    def __hash__(self) -> int:
+        return hash((self.constructor, self.arguments, ))
+
+    def __eq__(self, other: Any) -> bool:
+        if not isinstance(other, TypeApplication_Base):
+            raise NotImplementedError
+
+        return (self.constructor == other.constructor  # type: ignore[no-any-return]
+            and self.arguments == other.arguments)
+
     def __repr__(self) -> str:
         return f'{self.__class__.__name__}({self.constructor!r}, {self.arguments!r})'
 
@@ -84,7 +94,9 @@ class Type3(KindArgument):
         raise NotImplementedError
 
 class TypeApplication_Nullary(TypeApplication_Base[None, None]):
-    pass
+    """
+    There was no constructor used to create this type - it's a 'simple' type like u32
+    """
 
 class IntType3(KindArgument):
     """
@@ -104,6 +116,9 @@ class IntType3(KindArgument):
     def __init__(self, value: int) -> None:
         self.value = value
 
+    def __repr__(self) -> str:
+        return f'IntType3({self.value!r})'
+
     def __format__(self, format_spec: str) -> str:
         if format_spec != 's':
             raise TypeError(f'unsupported format string passed to Type3.__format__: {format_spec}')
@@ -177,6 +192,9 @@ class TypeConstructor_Base[T]:
 
         return result
 
+    def __repr__(self) -> str:
+        return f'{self.__class__.__name__}({self.name!r}, ...)'
+
 class TypeConstructor_TypeInt(TypeConstructor_Base[Tuple[Type3, IntType3]]):
     """
     Base class type constructors of kind: * -> Int -> *
diff --git a/phasm/wasmgenerator.py b/phasm/wasmgenerator.py
index 9268219..9bee38e 100644
--- a/phasm/wasmgenerator.py
+++ b/phasm/wasmgenerator.py
@@ -2,7 +2,7 @@
 Helper functions to generate WASM code by writing Python functions
 """
 import functools
-from typing import Any, Callable, Dict, List, Optional, Type
+from typing import Any, Callable, Dict, Iterable, List, Optional, Type
 
 from . import wasm
 
@@ -24,6 +24,12 @@ class VarType_i32(VarType_Base):
 class VarType_i64(VarType_Base):
     wasm_type = wasm.WasmTypeInt64
 
+class VarType_f32(VarType_Base):
+    wasm_type = wasm.WasmTypeFloat32
+
+class VarType_f64(VarType_Base):
+    wasm_type = wasm.WasmTypeFloat64
+
 class Generator_i32i64:
     def __init__(self, prefix: str, generator: 'Generator') -> None:
         self.prefix = prefix
@@ -164,12 +170,23 @@ class Generator_Local:
         self.generator.add_statement('local.tee', variable.name_ref, comment=comment)
 
 class GeneratorBlock:
-    def __init__(self, generator: 'Generator', name: str) -> None:
+    def __init__(self, generator: 'Generator', name: str, params: Iterable[str] = (), result: str | None = None) -> None:
         self.generator = generator
         self.name = name
+        self.params = params
+        self.result = result
 
     def __enter__(self) -> None:
-        self.generator.add_statement(self.name)
+        stmt = self.name
+        if self.params:
+            stmt = f'{stmt} ' + ' '.join(
+                f'(param {typ})'
+                for typ in self.params
+            )
+        if self.result:
+            stmt = f'{stmt} (result {self.result})'
+
+        self.generator.add_statement(stmt)
 
     def __exit__(self, exc_type: Any, exc_value: Any, traceback: Any) -> None:
         if not exc_type:
@@ -210,19 +227,18 @@ class Generator:
     def add_statement(self, name: str, *args: str, comment: Optional[str] = None) -> None:
         self.statements.append(wasm.Statement(name, *args, comment=comment))
 
-    def temp_var_i32(self, infix: str) -> VarType_i32:
+    def temp_var[T: VarType_Base](self, var: T) -> T:
         idx = 0
-        while (varname := f'__{infix}_tmp_var_{idx}__') in self.locals:
+        while (varname := f'__{var.name}_tmp_var_{idx}__') in self.locals:
             idx += 1
 
-        return VarType_i32(varname)
+        return var.__class__(varname)
+
+    def temp_var_i32(self, infix: str) -> VarType_i32:
+        return self.temp_var(VarType_i32(infix))
 
     def temp_var_u8(self, infix: str) -> VarType_u8:
-        idx = 0
-        while (varname := f'__{infix}_tmp_var_{idx}__') in self.locals:
-            idx += 1
-
-        return VarType_u8(varname)
+        return self.temp_var(VarType_u8(infix))
 
 def func_wrapper(exported: bool = True) -> Callable[[Any], wasm.Function]:
     """
diff --git a/tests/integration/helpers.py b/tests/integration/helpers.py
index a335509..74cfb19 100644
--- a/tests/integration/helpers.py
+++ b/tests/integration/helpers.py
@@ -17,6 +17,9 @@ from . import runners
 
 DASHES = '-' * 16
 
+class InvalidArgumentException(Exception):
+    pass
+
 class SuiteResult:
     def __init__(self) -> None:
         self.returned_value = None
@@ -152,18 +155,18 @@ def _allocate_memory_stored_bytes(attrs: tuple[runners.RunnerBase, bytes]) -> in
 def _allocate_memory_stored_static_array(attrs: tuple[runners.RunnerBase, Any], sa_args: tuple[type3types.Type3, type3types.IntType3]) -> int:
     runner, val = attrs
 
-    assert isinstance(val, tuple)
-
     sa_type, sa_len = sa_args
 
+    if not isinstance(val, tuple):
+        raise InvalidArgumentException(f'Expected tuple of length {sa_len.value}; got {val!r} instead')
+    if sa_len.value != len(val):
+        raise InvalidArgumentException(f'Expected tuple of length {sa_len.value}; got {val!r} instead')
+
     alloc_size = calculate_alloc_size_static_array(False, sa_args)
     adr = runner.call('stdlib.alloc.__alloc__', alloc_size)
-    assert isinstance(adr, int)
+    assert isinstance(adr, int)  # Type int
     sys.stderr.write(f'Allocation 0x{adr:08x} {repr(val)}\n')
 
-    tuple_len = sa_len.value
-    assert tuple_len == len(val)
-
     offset = adr
     for val_el_val in val:
         offset += _write_memory_stored_value(runner, offset, sa_type, val_el_val)
diff --git a/tests/integration/test_lang/test_foldable.py b/tests/integration/test_lang/test_foldable.py
new file mode 100644
index 0000000..c03d6e7
--- /dev/null
+++ b/tests/integration/test_lang/test_foldable.py
@@ -0,0 +1,71 @@
+import pytest
+
+from phasm.type3.entry import Type3Exception
+
+from ..helpers import Suite
+from .test_natnum import FLOAT_TYPES, INT_TYPES
+
+
+@pytest.mark.integration_test
+@pytest.mark.parametrize('length', [1, 5, 13])
+@pytest.mark.parametrize('a_type', INT_TYPES + FLOAT_TYPES)
+def test_foldable_sum(length, a_type):
+    code_py = f"""
+@exported
+def testEntry(x: {a_type}[{length}]) -> {a_type}:
+    return sum(x)
+"""
+
+    in_put = tuple(range(length))
+
+    result = Suite(code_py).run_code(in_put)
+
+    assert sum(in_put) == result.returned_value
+
+@pytest.mark.integration_test
+def test_foldable_sum_not_natnum():
+    code_py = """
+class Foo:
+    bar: i32
+
+@exported
+def testEntry(x: Foo[4]) -> Foo:
+    return sum(x)
+"""
+
+    with pytest.raises(Type3Exception, match='Missing type class instantation: NatNum Foo'):
+        Suite(code_py).run_code()
+
+
+@pytest.mark.integration_test
+def test_foldable_invalid_return_type():
+    code_py = """
+@exported
+def testEntry(x: i32[5]) -> f64:
+    return sum(x)
+"""
+
+    with pytest.raises(Type3Exception, match='i32 must be f64 instead'):
+        Suite(code_py).run_code((4, 5, 6, 7, 8, ))
+
+@pytest.mark.integration_test
+def test_foldable_not_constructed():
+    code_py = """
+@exported
+def testEntry(x: i32) -> i32:
+    return sum(x)
+"""
+
+    with pytest.raises(Type3Exception, match='Missing type class instantation: Foldable i32.*i32 must be a constructed type instead'):
+        Suite(code_py).run_code()
+
+@pytest.mark.integration_test
+def test_foldable_not_foldable():
+    code_py = """
+@exported
+def testEntry(x: (i32, u32, )) -> i32:
+    return sum(x)
+"""
+
+    with pytest.raises(Type3Exception, match='Missing type class instantation: Foldable tuple'):
+        Suite(code_py).run_code()