fix(core): remove unused CoreResult type alias, standardize on LintResult (#477) (#520)

* fix(core): remove unused CoreResult type alias, standardize on LintResult (#477)

CoreResult<T> was defined and re-exported but never used anywhere in the
codebase. LintResult<T> is the established convention used in 40+ locations.
Since LintError is already an alias for CoreError, both aliases resolved to
the same type - CoreResult was pure dead code.

Closes #477

* test(core): strengthen lint_result_is_sole_result_alias with functional assertions

Replace trivially-true type_name checks with concrete Err construction
using CoreError::Validation variants, verifying the LintResult<T> =
Result<T, LintError> = Result<T, CoreError> chain end-to-end.

* fix(core): address review feedback on CoreResult removal (#477)

- Add CoreError to public_types_are_importable contract test
- Replace panic! with unreachable! in test catch-all arm
- Upgrade LintError alias comment to rustdoc (/// style)
- Expand CHANGELOG migration note to clarify LintError/CoreError relationship

* test(core): exhaustively match all CoreError variants in lint_result_is_sole_result_alias

Replace wildcard arm with explicit File/Validation/Config arms so the match
is truly exhaustive. A new CoreError variant will now cause a compile error
in this test rather than silently passing.

* docs: add LintError and LintResult to diagnostics.rs module description (#477)

The diagnostics.rs entry in CLAUDE.md/AGENTS.md omitted LintError and
LintResult, which are the primary public error types from that module.
With CoreResult removed, LintResult is now the sole public Result alias
- making this an appropriate time to document both types explicitly.

* fix(core): address rustfmt formatting issues

Reformat pub use statement in lib.rs and struct initialization in test to comply with cargo fmt standards.

Author: avifenesh

AGENTS.md

@@ -68,7 +68,7 @@ tests/fixtures/     # Test cases by category
 - `schemas/` - Type definitions (13 schemas: skill, hooks, agent, mcp, cline, roo, etc.)
 - `rules/` - Validators implementing Validator trait (25 validators)
 - `config.rs` - LintConfig, LintConfigBuilder, ConfigError, ToolVersions, SpecRevisions
-- `diagnostics.rs` - Diagnostic, Fix, DiagnosticLevel, ValidationOutcome
+- `diagnostics.rs` - Diagnostic, Fix, DiagnosticLevel, ValidationOutcome, LintError (= CoreError), LintResult
 - `eval.rs` - Rule efficacy evaluation (precision/recall/F1)
 - `file_types/` - FileType enum, detect_file_type(), FileTypeDetector trait, FileTypeDetectorChain
 - `file_utils.rs` - Safe file I/O (symlink rejection, size limits)

CHANGELOG.md

@@ -35,6 +35,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - **`MAX_REGEX_INPUT_SIZE` precise boundary tests**: 27 tests covering the exact 65536-byte limit for all 12 guarded regex functions across `markdown.rs`, `prompt.rs`, and `cross_platform.rs` - each function gets an at-limit (processed) and one-byte-over (rejected) test; also confirms `extract_imports` and `extract_markdown_links` are unrestricted (byte-scan/pulldown-cmark, not regex) (#457)
 
 ### Changed
+- **`CoreResult` type alias removed** (breaking): `CoreResult<T>` has been removed from the public API. Use `LintResult<T>` (i.e., `Result<T, LintError>`) instead. `LintError` is a public alias for `CoreError`; both remain exported. (#477)
 - **`__internal` module feature-gated**: The `__internal` module in `agnix-core` is now behind the `__internal` Cargo feature; it was previously unconditionally public which created semver obligations for internal items (#472)
 - **`normalize_line_endings` promoted to stable public API**: Accessible at the crate root (`agnix_core::normalize_line_endings`) without requiring the `__internal` feature (#472)
 - **Project-level validation extracted to `rules/project_level.rs`**: Extracted `run_project_level_checks`, `join_paths`, and associated unit tests from `pipeline.rs` into a new `rules/project_level.rs` module; adds 7 new unit tests for AGM-006, XP-004/005/006, and VER-001 behaviors (#474)

CLAUDE.md

@@ -68,7 +68,7 @@ tests/fixtures/     # Test cases by category
 - `schemas/` - Type definitions (13 schemas: skill, hooks, agent, mcp, cline, roo, etc.)
 - `rules/` - Validators implementing Validator trait (25 validators)
 - `config.rs` - LintConfig, LintConfigBuilder, ConfigError, ToolVersions, SpecRevisions
-- `diagnostics.rs` - Diagnostic, Fix, DiagnosticLevel, ValidationOutcome
+- `diagnostics.rs` - Diagnostic, Fix, DiagnosticLevel, ValidationOutcome, LintError (= CoreError), LintResult
 - `eval.rs` - Rule efficacy evaluation (precision/recall/F1)
 - `file_types/` - FileType enum, detect_file_type(), FileTypeDetector trait, FileTypeDetectorChain
 - `file_utils.rs` - Safe file I/O (symlink rejection, size limits)

crates/agnix-core/src/diagnostics.rs

@@ -7,7 +7,6 @@ use std::path::PathBuf;
 use thiserror::Error;
 
 pub type LintResult<T> = Result<T, LintError>;
-pub type CoreResult<T> = Result<T, CoreError>;
 
 /// An automatic fix for a diagnostic
 #[derive(Debug, Clone, Serialize, Deserialize)]
@@ -673,7 +672,11 @@ impl CoreError {
     }
 }
 
-// Backward compatibility: LintError is now an alias for CoreError
+/// `LintError` is the canonical public name for [`CoreError`].
+///
+/// Both names are re-exported at the crate root. Internal code constructs
+/// variants via `CoreError`; public API surfaces and function signatures
+/// use `LintError` and [`LintResult`].
 pub type LintError = CoreError;
 
 /// Outcome of validating a single file.

crates/agnix-core/src/lib.rs

@@ -89,8 +89,8 @@ pub mod validation;
 
 pub use config::{ConfigWarning, FilesConfig, LintConfig, generate_schema};
 pub use diagnostics::{
-    ConfigError, CoreError, CoreResult, Diagnostic, DiagnosticLevel, FileError, Fix,
-    FixConfidenceTier, LintError, LintResult, RuleMetadata, ValidationError, ValidationOutcome,
+    ConfigError, CoreError, Diagnostic, DiagnosticLevel, FileError, Fix, FixConfidenceTier,
+    LintError, LintResult, RuleMetadata, ValidationError, ValidationOutcome,
 };
 pub use file_types::{FileType, detect_file_type};
 pub use file_types::{FileTypeDetector, FileTypeDetectorChain};

crates/agnix-core/tests/api_contract.rs

@@ -28,7 +28,10 @@ fn public_types_are_importable() {
     let _ = std::any::type_name::<agnix_core::FilesConfig>();
     let _ = std::any::type_name::<agnix_core::ValidationOutcome>();
 
-    // LintResult type alias
+    // Error types: CoreError is the concrete enum; LintError is its public alias.
+    // Both are re-exported. CoreResult was removed in #477.
+    let _ = std::any::type_name::<agnix_core::CoreError>();
+    // LintResult type alias - the sole public Result alias.
     let _ = std::any::type_name::<agnix_core::LintResult<()>>();
 
     // ValidatorFactory type alias
@@ -1136,3 +1139,41 @@ fn normalize_line_endings_lf_only_is_borrowed_and_zero_copy() {
         "Cow::Borrowed must point to the original allocation"
     );
 }
+
+// ============================================================================
+// LintResult is the sole public Result alias (#477)
+// ============================================================================
+
+/// Verify that `LintResult<T>` is the sole public Result alias in agnix-core.
+///
+/// `CoreResult<T>` was removed in #477 because it was dead code - defined and
+/// re-exported but never used anywhere in the codebase. `LintResult<T>` is the
+/// established convention used across 40+ call sites.
+#[test]
+fn lint_result_is_sole_result_alias() {
+    use agnix_core::{CoreError, LintError, LintResult, ValidationError};
+
+    // LintResult<T> must accept Ok values.
+    let ok: LintResult<u32> = Ok(42);
+    assert_eq!(ok.unwrap(), 42);
+
+    // LintResult<T> must accept Err values constructed from a concrete CoreError variant.
+    // This verifies LintResult<T> = Result<T, LintError> = Result<T, CoreError> end-to-end.
+    let err: LintResult<u32> = Err(CoreError::Validation(ValidationError::TooManyFiles {
+        count: 9999,
+        limit: 1000,
+    }));
+    assert!(err.is_err());
+
+    // LintError and CoreError are type aliases for the same enum - constructing
+    // one variant via CoreError and matching through LintError must work.
+    let lint_err: LintError =
+        CoreError::Validation(ValidationError::TooManyFiles { count: 1, limit: 0 });
+    // Exhaustively match all three CoreError variants through the LintError alias.
+    // If a new CoreError variant is added, this match will fail to compile.
+    match lint_err {
+        LintError::File(_) => {}
+        LintError::Validation(_) => {}
+        LintError::Config(_) => {}
+    }
+}