chore: Move templated code for assert_message into the stdlib (#4475)

# Description

## Problem\*

We currently have a noirc_macros crate which checks for the stdlib and
inserts two functions into the stdlib. The motivation being that we did
not want users to be able to see these functions.

Introducing a new crate for this reason, does not seem to be worth it
since its ~7 lines of noir code.


## Solution\*

This PR removes the noirc_macros crate and copies the noir code that was
being pasted into the stdlib, directly into the stdlib

## Additional Context



## Documentation\*

Check one:
- [ ] No documentation needed.
- [ ] Documentation included in this PR.
- [ ] **[Exceptional Case]** Documentation to be submitted in a separate
PR.

# PR Checklist\*

- [ ] I have tested the changes locally.
- [ ] I have formatted the changes with [Prettier](https://prettier.io/)
and/or `cargo fmt` on default settings.

---------

Co-authored-by: Tom French <[email protected]>
Co-authored-by: Tom French <[email protected]>

Cargo.toml

@@ -1,9 +1,8 @@
 [workspace]
 
 members = [
-    # Macros crates for metaprogramming
+    # Aztec Macro crate for metaprogramming
     "aztec_macros",
-    "noirc_macros",
     # Compiler crates
     "compiler/noirc_evaluator",
     "compiler/noirc_frontend",

compiler/noirc_driver/Cargo.toml

@@ -26,4 +26,3 @@ tracing.workspace = true
 thiserror.workspace = true
 
 aztec_macros = { path = "../../aztec_macros" }
-noirc_macros = { path = "../../noirc_macros" }

compiler/noirc_driver/src/lib.rs

@@ -238,12 +238,9 @@ pub fn check_crate(
     disable_macros: bool,
 ) -> CompilationResult<()> {
     let macros: Vec<&dyn MacroProcessor> = if disable_macros {
-        vec![&noirc_macros::AssertMessageMacro as &dyn MacroProcessor]
+        vec![]
     } else {
-        vec![
-            &aztec_macros::AztecMacro as &dyn MacroProcessor,
-            &noirc_macros::AssertMessageMacro as &dyn MacroProcessor,
-        ]
+        vec![&aztec_macros::AztecMacro as &dyn MacroProcessor]
     };
 
     let mut errors = vec![];

compiler/noirc_frontend/src/hir/resolution/resolver.rs

@@ -1256,13 +1256,17 @@ impl<'a> Resolver<'a> {
         let is_in_stdlib = self.path_resolver.module_id().krate.is_stdlib();
         let assert_msg_call_path = if is_in_stdlib {
             ExpressionKind::Variable(Path {
-                segments: vec![Ident::from("resolve_assert_message")],
+                segments: vec![Ident::from("internal"), Ident::from("resolve_assert_message")],
                 kind: PathKind::Crate,
                 span,
             })
         } else {
             ExpressionKind::Variable(Path {
-                segments: vec![Ident::from("std"), Ident::from("resolve_assert_message")],
+                segments: vec![
+                    Ident::from("std"),
+                    Ident::from("internal"),
+                    Ident::from("resolve_assert_message"),
+                ],
                 kind: PathKind::Dep,
                 span,
             })

noir_stdlib/src/internal.nr

@@ -0,0 +1,12 @@
+// This file contains functions which should only be used in calls injected by the Noir compiler.
+// These functions should not be called manually in user code.
+//
+// Changes to this file will not be considered breaking.
+
+#[oracle(assert_message)]
+unconstrained fn assert_message_oracle<T>(_input: T) {}
+unconstrained pub fn resolve_assert_message<T>(input: T, condition: bool) {
+    if !condition {
+        assert_message_oracle(input);
+    }
+}

noir_stdlib/src/lib.nr

@@ -26,6 +26,7 @@ mod default;
 mod prelude;
 mod uint128;
 mod bigint;
+mod internal;
 
 // Oracle calls are required to be wrapped in an unconstrained function
 // Thus, the only argument to the `println` oracle is expected to always be an ident