feat: higher order fns can now be called with closures

crates/nargo_cli/tests/execution_success/closures_passed_to_higher_order_fns/Nargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "closures_passed_to_higher_order_fns"
+type = "bin"
+authors = [""]
+compiler_version = "0.1"
+
+[dependencies]

crates/nargo_cli/tests/execution_success/closures_passed_to_higher_order_fns/src/main.nr

@@ -0,0 +1,31 @@
+use dep::std;
+
+fn main() { 
+    // give some numbers names to turn them into variables for capturing
+    let _0: u32 = 0;
+    let _1: u32 = 1;
+    let _2: u32 = 2;
+    let _5: u32 = 5;
+
+    let arr: [u32; 3] = [1, 2, 3];
+    let evens = arr.map(|n| n * _2);
+
+    assert(arr.any(|n| n > _1));
+    assert(arr.all(|n| n > _0 & n < _5));
+
+    assert(evens.fold(0, |a, b| a + b + _1) == 15);
+    assert(evens.reduce(|a, b| a + b + _1) == 14);
+
+    // call with 1 captured variable
+    assert(add_results(|| _5, || _2) == 7);
+
+    // call with 2 captured variables
+    assert(add_results(|| _5 + _2, || _2 + _1) == 10);
+
+    // call with different environment types for the 2 args
+    assert(add_results(|| _5 + _2, || _2) == 9);
+}
+
+fn add_results(a: fn () -> u32, b: fn () -> u32) -> u32 {
+    a() + b()
+}

crates/nargo_cli/tests/execution_success/closures_passed_to_higher_order_fns/target/higher_order_functions.json

@@ -0,0 +1 @@
+{"backend":"acvm-backend-barretenberg","abi":{"parameters":[],"param_witnesses":{},"return_type":{"kind":"field"},"return_witnesses":[83]},"bytecode":"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","proving_key":null,"verification_key":null}

crates/noirc_frontend/src/hir_def/types.rs

@@ -1090,10 +1090,6 @@ impl Type {
     /// given bindings if found. If a type variable is not found within
     /// the given TypeBindings, it is unchanged.
     pub fn substitute(&self, type_bindings: &TypeBindings) -> Type {
-        if type_bindings.is_empty() {
-            return self.clone();
-        }
-
         let substitute_binding = |binding: &TypeVariable| match &*binding.borrow() {
             TypeBinding::Bound(binding) => binding.substitute(type_bindings),
             TypeBinding::Unbound(id) => match type_bindings.get(id) {