feat: plan 06 diagnostics

.sampo/changesets/report-foundation.md

@@ -0,0 +1,6 @@
+---
+cargo/nash-report: minor
+cargo/nash-parse: patch
+---
+
+Add compiler report documents, source spans, terminal rendering and name suggestions. Expose parser token classifiers and preserve nested parse errors for diagnostics.

.sampo/changesets/report-wiring.md

@@ -0,0 +1,10 @@
+---
+cargo/nash-can: patch
+cargo/nash-constrain: patch
+cargo/nash-solve: patch
+cargo/nash-driver: minor
+cargo/nash-cli: minor
+cargo/nash-language-server: minor
+---
+
+Collect independent compiler errors with dependency-aware recovery, retain failed module dependencies, and render owned diagnostics in the terminal, JSON, and language server. Preserve trait-method call names in error context. Add JSON and warning controls to `nash check`, and publish diagnostics for unsaved editor buffers with UTF-16 ranges.

Cargo.toml

@@ -27,6 +27,7 @@ octocrab = { version = "0.49.5", features = ["stream"] }
 pretty_assertions = "1.4.0"
 pubgrub = { version = "0.3", features = ["serde"] }
 serde = { version = "1", features = ["derive"] }
+serde_json = "1"
 tar = "0.4"
 thiserror = "2"
 tokio = { version = "1", features = ["fs", "macros", "rt-multi-thread", "sync"] }

SPEC.md

@@ -27,7 +27,7 @@ produce UPLC programs; all dependencies inline into each program.
 | `nash-constrain` | constraint generation, kinds | extend |
 | `nash-solve` | solver, traits, defaulting | extend |
 | `nash-nitpick` | exhaustiveness and redundancy | done ([plans/05](plans/05-nitpick.md)) |
-| `nash-report` | diagnostics (Elm prose -> miette) | new ([plans/06](plans/06-diagnostics.md)) |
+| `nash-report` | diagnostics (Elm prose -> miette) | done ([plans/06](plans/06-diagnostics.md)) |
 | `nash-ir` | Core IR + passes | new ([plans/07](plans/07-codegen.md), [08](plans/08-optimizer.md)) |
 | `nash-codegen` | Can -> Core -> UPLC | new ([plans/07](plans/07-codegen.md)) |
 | `nash-test` | test runner, fuzzing, shrinking | new ([plans/10](plans/10-testing.md)) |
@@ -37,7 +37,7 @@ produce UPLC programs; all dependencies inline into each program.
 | `nash-config` | `nash.jsonc` | done, extend |
 | `nash-driver` | build graph, caching | done, extend |
 | `nash-cli` | `nash` binary | `check`, `lsp`; add `build test fmt docs` |
-| `nash-language-server` | LSP | stub |
+| `nash-language-server` | LSP | live compiler diagnostics with UTF-16 ranges |
 | `core/` | `nash/core` stdlib package (Nash source) | new ([plans/12](plans/12-stdlib.md)) |
 
 ## Progress
@@ -60,7 +60,7 @@ Planned, in execution order (each links to its plan):
 - [x] 03 Traits: qualified types, resolution, superclasses, defaults, multi-param, orphan rules, literal traits + defaulting, evidence — [plans/03-traits.md](plans/03-traits.md) (default imports deferred to Plan 12)
 - [x] 04 Representation: remove row polymorphism and Elm supertypes, builtin type inventory, record encoding — [plans/04-representation.md](plans/04-representation.md)
 - [x] 05 Exhaustiveness (`Nitpick/PatternMatches` port) — [plans/05-nitpick.md](plans/05-nitpick.md)
-- [ ] 06 Diagnostics (`nash-report`, Elm `Reporting/*` port onto miette) — [plans/06-diagnostics.md](plans/06-diagnostics.md)
+- [x] 06 Diagnostics (`nash-report`, Elm `Reporting/*` port onto miette) — [plans/06-diagnostics.md](plans/06-diagnostics.md)
 - [ ] 07 Codegen: Core IR, monomorphization, decision trees, recursion, Data casts, UPLC lowering — [plans/07-codegen.md](plans/07-codegen.md)
 - [ ] 08 Optimizer: inlining, builtin force caching, DCE, case-of-known-ctor/constant folding — [plans/08-optimizer.md](plans/08-optimizer.md)
 - [ ] 09 Validators + `nash build` — [plans/09-validators-build.md](plans/09-validators-build.md)
@@ -83,7 +83,7 @@ Later: LSP features, web playground, package registry (pubgrub), TypeScript code
 | `Type/Type.hs`, `Type/Constrain/*` | `crates/nash-constrain/src/*` |
 | `Type/{Solve,Unify,Occurs}.hs` | `crates/nash-solve/src/*` |
 | `Nitpick/PatternMatches.hs` | `crates/nash-nitpick` |
-| `Reporting/{Doc,Report,Render,Suggest}.hs`, `Reporting/Error/*` | `crates/nash-report` (planned) |
+| `Reporting/{Doc,Report,Render,Suggest}.hs`, `Reporting/Error/*` | `crates/nash-report` |
 | `builder/src/Elm/Outline.hs` | `crates/nash-config` |
 | `builder/src/Build.hs` | `crates/nash-driver` |
 

crates/nash-can/src/lib.rs

@@ -15,7 +15,7 @@ pub mod warning;
 
 pub use crate::entailment::Failure as EntailmentFailure;
 pub use crate::error::{
-    BadArityContext, DuplicatePatternContext, Error, KindContext, PossibleNames, VarKind,
+    BadArityContext, BadHead, DuplicatePatternContext, Error, KindContext, PossibleNames, VarKind,
 };
 pub use crate::interface::{
     AliasVisibility, Annotations, Interface, InterfaceAlias, InterfaceBinop, InterfaceMethod,

crates/nash-cli/Cargo.toml

@@ -21,7 +21,9 @@ color-print.workspace = true
 dirs.workspace = true
 futures.workspace = true
 miette.workspace = true
+serde_json.workspace = true
 nash-config = { path = "../nash-config", version = "0.3.0" }
+nash-report = { path = "../nash-report", version = "0.1.0" }
 nash-driver = { path = "../nash-driver", version = "0.4.0" }
 nash-language-server = { path = "../nash-language-server", version = "0.2.0" }
 octocrab.workspace = true
@@ -31,3 +33,6 @@ tokio-util = { version = "0.7.18", features = ["compat"] }
 tower-lsp-server.workspace = true
 xz2.workspace = true
 zip.workspace = true
+
+[dev-dependencies]
+insta.workspace = true

crates/nash-cli/src/cli.rs

@@ -1,15 +1,26 @@
 use clap::Parser;
+use std::io::IsTerminal;
 
 use crate::cmd;
 
 #[derive(Parser)]
 #[command(name = "nash", version, about = "The Nash programming language compiler", long_about = Some(crate::BANNER))]
 #[command(propagate_version = true)]
 pub struct Cli {
+    /// Control diagnostic colors. NO_COLOR disables automatic colors.
+    #[arg(long, global = true, value_enum, default_value = "auto")]
+    pub color: Color,
     #[command(subcommand)]
     pub cmd: cmd::Cmd,
 }
 
+#[derive(Clone, Copy, clap::ValueEnum)]
+pub enum Color {
+    Auto,
+    Always,
+    Never,
+}
+
 impl Default for Cli {
     fn default() -> Self {
         Self::parse()
@@ -18,6 +29,14 @@ impl Default for Cli {
 
 impl Cli {
     pub async fn exec(self) -> miette::Result<()> {
-        self.cmd.exec().await
+        let color = match self.color {
+            Color::Always => true,
+            Color::Never => false,
+            Color::Auto => {
+                std::io::stderr().is_terminal() && std::env::var_os("NO_COLOR").is_none()
+            }
+        };
+        miette::set_hook(Box::new(move |_| Box::new(nash_report::handler(color))))?;
+        self.cmd.exec(color).await
     }
 }