Rollup merge of #68079 - varkor:E0013-clarify, r=Centril

[rust.git] / src / librustc_session / parse.rs

diff --git a/src/librustc_session/parse.rs b/src/librustc_session/parse.rs
index 0c6295a184c7c27842be877abdd448e8796078e8..946e77d35595e101ee35d03844c75e9becbef0e7 100644 (file)
--- a/src/librustc_session/parse.rs
+++ b/src/librustc_session/parse.rs
@@ -1,19 +1,19 @@
 //! Contains `ParseSess` which holds state living beyond what one `Parser` might.
 //! It also serves as an input to the parser itself.
 
-use crate::lint::BufferedEarlyLint;
+use crate::lint::{BufferedEarlyLint, BuiltinLintDiagnostics, Lint, LintId};
 use crate::node_id::NodeId;
 
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::sync::{Lock, Lrc, Once};
-use rustc_errors::{
-    emitter::SilentEmitter, Applicability, ColorConfig, DiagnosticBuilder, Handler,
-};
-use rustc_feature::UnstableFeatures;
-use syntax_pos::edition::Edition;
-use syntax_pos::hygiene::ExpnId;
-use syntax_pos::source_map::{FilePathMapping, SourceMap};
-use syntax_pos::{MultiSpan, Span, Symbol};
+use rustc_error_codes::E0658;
+use rustc_errors::{emitter::SilentEmitter, ColorConfig, Handler};
+use rustc_errors::{error_code, Applicability, DiagnosticBuilder};
+use rustc_feature::{find_feature_issue, GateIssue, UnstableFeatures};
+use rustc_span::edition::Edition;
+use rustc_span::hygiene::ExpnId;
+use rustc_span::source_map::{FilePathMapping, SourceMap};
+use rustc_span::{MultiSpan, Span, Symbol};
 
 use std::path::PathBuf;
 use std::str;
@@ -62,6 +62,81 @@ pub fn merge(&self, mut spans: FxHashMap<Symbol, Vec<Span>>) {
     }
 }
 
+/// The strenght of a feature gate.
+/// Either it is a `Hard` error, or only a `Soft` warning.
+#[derive(Debug, Copy, Clone, PartialEq)]
+pub enum GateStrength {
+    /// A hard error. (Most feature gates should use this.)
+    Hard,
+    /// Only a warning. (Use this only as backwards-compatibility demands.)
+    Soft,
+}
+
+/// Construct a diagnostic for a language feature error due to the given `span`.
+/// The `feature`'s `Symbol` is the one you used in `active.rs` and `rustc_span::symbols`.
+pub fn feature_err<'a>(
+    sess: &'a ParseSess,
+    feature: Symbol,
+    span: impl Into<MultiSpan>,
+    explain: &str,
+) -> DiagnosticBuilder<'a> {
+    feature_err_issue(sess, feature, span, GateIssue::Language, explain)
+}
+
+/// Construct a diagnostic for a feature gate error.
+///
+/// This variant allows you to control whether it is a library or language feature.
+/// Almost always, you want to use this for a language feature. If so, prefer `feature_err`.
+pub fn feature_err_issue<'a>(
+    sess: &'a ParseSess,
+    feature: Symbol,
+    span: impl Into<MultiSpan>,
+    issue: GateIssue,
+    explain: &str,
+) -> DiagnosticBuilder<'a> {
+    leveled_feature_err(sess, feature, span, issue, explain, GateStrength::Hard)
+}
+
+/// Construct a diagnostic for a feature gate error / warning.
+///
+/// You should typically just use `feature_err` instead.
+pub fn leveled_feature_err<'a>(
+    sess: &'a ParseSess,
+    feature: Symbol,
+    span: impl Into<MultiSpan>,
+    issue: GateIssue,
+    explain: &str,
+    level: GateStrength,
+) -> DiagnosticBuilder<'a> {
+    let diag = &sess.span_diagnostic;
+
+    let mut err = match level {
+        GateStrength::Hard => diag.struct_span_err_with_code(span, explain, error_code!(E0658)),
+        GateStrength::Soft => diag.struct_span_warn(span, explain),
+    };
+
+    if let Some(n) = find_feature_issue(feature, issue) {
+        err.note(&format!(
+            "for more information, see https://github.com/rust-lang/rust/issues/{}",
+            n,
+        ));
+    }
+
+    // #23973: do not suggest `#![feature(...)]` if we are in beta/stable
+    if sess.unstable_features.is_nightly_build() {
+        err.help(&format!("add `#![feature({})]` to the crate attributes to enable", feature));
+    }
+
+    // If we're on stable and only emitting a "soft" warning, add a note to
+    // clarify that the feature isn't "on" (rather than being on but
+    // warning-worthy).
+    if !sess.unstable_features.is_nightly_build() && level == GateStrength::Soft {
+        err.help("a nightly build of the compiler is required to enable this feature");
+    }
+
+    err
+}
+
 /// Info about a parsing session.
 pub struct ParseSess {
     pub span_diagnostic: Handler,
@@ -123,17 +198,18 @@ pub fn source_map(&self) -> &SourceMap {
 
     pub fn buffer_lint(
         &self,
-        lint_id: &'static crate::lint::Lint,
+        lint: &'static Lint,
         span: impl Into<MultiSpan>,
-        id: NodeId,
+        node_id: NodeId,
         msg: &str,
     ) {
         self.buffered_lints.with_lock(|buffered_lints| {
             buffered_lints.push(BufferedEarlyLint {
                 span: span.into(),
-                id,
+                node_id,
                 msg: msg.into(),
-                lint_id,
+                lint_id: LintId::of(lint),
+                diagnostic: BuiltinLintDiagnostics::Normal,
             });
         });
     }