Streamline struct_lint_level.

We can just get the error level in the `match` and then use
`DiagnosticBuilder::new`. This then means a number of `DiagCtxt`
functions are no longer needed, because this was the one place that used
them.

Note: the commit changes the treatment of spans for `Expect`, which was
different to all the other cases, but this has no apparent effect.

compiler/rustc_errors/src/lib.rs

@@ -740,37 +740,6 @@ impl DiagCtxt {
         result
     }
 
-    /// Construct a builder at the `Warning` level at the given `span` and with the `msg`.
-    /// The `id` is used for lint emissions which should also fulfill a lint expectation.
-    ///
-    /// Attempting to `.emit()` the builder will only emit if either:
-    /// * `can_emit_warnings` is `true`
-    /// * `is_force_warn` was set in `DiagnosticId::Lint`
-    #[track_caller]
-    pub fn struct_span_warn_with_expectation(
-        &self,
-        span: impl Into<MultiSpan>,
-        msg: impl Into<DiagnosticMessage>,
-        id: LintExpectationId,
-    ) -> DiagnosticBuilder<'_, ()> {
-        let mut result = self.struct_warn_with_expectation(msg, id);
-        result.set_span(span);
-        result
-    }
-
-    /// Construct a builder at the `Allow` level at the given `span` and with the `msg`.
-    #[rustc_lint_diagnostics]
-    #[track_caller]
-    pub fn struct_span_allow(
-        &self,
-        span: impl Into<MultiSpan>,
-        msg: impl Into<DiagnosticMessage>,
-    ) -> DiagnosticBuilder<'_, ()> {
-        let mut result = self.struct_allow(msg);
-        result.set_span(span);
-        result
-    }
-
     /// Construct a builder at the `Warning` level at the given `span` and with the `msg`.
     /// Also include a code.
     #[rustc_lint_diagnostics]
@@ -797,21 +766,6 @@ impl DiagCtxt {
         DiagnosticBuilder::new(self, Level::Warning(None), msg)
     }
 
-    /// Construct a builder at the `Warning` level with the `msg`. The `id` is used for
-    /// lint emissions which should also fulfill a lint expectation.
-    ///
-    /// Attempting to `.emit()` the builder will only emit if either:
-    /// * `can_emit_warnings` is `true`
-    /// * `is_force_warn` was set in `DiagnosticId::Lint`
-    #[track_caller]
-    pub fn struct_warn_with_expectation(
-        &self,
-        msg: impl Into<DiagnosticMessage>,
-        id: LintExpectationId,
-    ) -> DiagnosticBuilder<'_, ()> {
-        DiagnosticBuilder::new(self, Level::Warning(Some(id)), msg)
-    }
-
     /// Construct a builder at the `Allow` level with the `msg`.
     #[rustc_lint_diagnostics]
     #[track_caller]
@@ -868,13 +822,6 @@ impl DiagCtxt {
         DiagnosticBuilder::new(self, Level::Error { lint: false }, msg)
     }
 
-    /// This should only be used by `rustc_middle::lint::struct_lint_level`. Do not use it for hard errors.
-    #[doc(hidden)]
-    #[track_caller]
-    pub fn struct_err_lint(&self, msg: impl Into<DiagnosticMessage>) -> DiagnosticBuilder<'_, ()> {
-        DiagnosticBuilder::new(self, Level::Error { lint: true }, msg)
-    }
-
     /// Construct a builder at the `Error` level with the `msg` and the `code`.
     #[rustc_lint_diagnostics]
     #[track_caller]

compiler/rustc_middle/src/lint.rs

@@ -293,19 +293,16 @@ pub fn struct_lint_level(
             },
         );
 
-        let mut err = match (level, span) {
+        // Convert lint level to error level.
-            (Level::Allow, span) => {
+        let err_level = match level {
+            Level::Allow => {
                 if has_future_breakage {
-                    if let Some(span) = span {
+                    rustc_errors::Level::Allow
-                        sess.struct_span_allow(span, "")
-                    } else {
-                        sess.struct_allow("")
-                    }
                 } else {
                     return;
                 }
             }
-            (Level::Expect(expect_id), _) => {
+            Level::Expect(expect_id) => {
                 // This case is special as we actually allow the lint itself in this context, but
                 // we can't return early like in the case for `Level::Allow` because we still
                 // need the lint diagnostic to be emitted to `rustc_error::DiagCtxtInner`.
@@ -313,23 +310,16 @@ pub fn struct_lint_level(
                 // We can also not mark the lint expectation as fulfilled here right away, as it
                 // can still be cancelled in the decorate function. All of this means that we simply
                 // create a `DiagnosticBuilder` and continue as we would for warnings.
-                sess.struct_expect("", expect_id)
+                rustc_errors::Level::Expect(expect_id)
             }
-            (Level::ForceWarn(Some(expect_id)), Some(span)) => {
+            Level::ForceWarn(Some(expect_id)) => rustc_errors::Level::Warning(Some(expect_id)),
-                sess.struct_span_warn_with_expectation(span, "", expect_id)
+            Level::Warn | Level::ForceWarn(None) => rustc_errors::Level::Warning(None),
-            }
+            Level::Deny | Level::Forbid => rustc_errors::Level::Error { lint: true },
-            (Level::ForceWarn(Some(expect_id)), None) => {
-                sess.struct_warn_with_expectation("", expect_id)
-            }
-            (Level::Warn | Level::ForceWarn(None), Some(span)) => sess.struct_span_warn(span, ""),
-            (Level::Warn | Level::ForceWarn(None), None) => sess.struct_warn(""),
-            (Level::Deny | Level::Forbid, Some(span)) => {
-                let mut builder = sess.dcx().struct_err_lint("");
-                builder.set_span(span);
-                builder
-            }
-            (Level::Deny | Level::Forbid, None) => sess.dcx().struct_err_lint(""),
         };
+        let mut err = DiagnosticBuilder::new(sess.dcx(), err_level, "");
+        if let Some(span) = span {
+            err.set_span(span);
+        }
 
         err.set_is_lint();
 

compiler/rustc_session/src/session.rs

@@ -321,16 +321,6 @@ impl Session {
     }
     #[rustc_lint_diagnostics]
     #[track_caller]
-    pub fn struct_span_warn_with_expectation<S: Into<MultiSpan>>(
-        &self,
-        sp: S,
-        msg: impl Into<DiagnosticMessage>,
-        id: lint::LintExpectationId,
-    ) -> DiagnosticBuilder<'_, ()> {
-        self.dcx().struct_span_warn_with_expectation(sp, msg, id)
-    }
-    #[rustc_lint_diagnostics]
-    #[track_caller]
     pub fn struct_span_warn_with_code<S: Into<MultiSpan>>(
         &self,
         sp: S,
@@ -346,24 +336,6 @@ impl Session {
     }
     #[rustc_lint_diagnostics]
     #[track_caller]
-    pub fn struct_warn_with_expectation(
-        &self,
-        msg: impl Into<DiagnosticMessage>,
-        id: lint::LintExpectationId,
-    ) -> DiagnosticBuilder<'_, ()> {
-        self.dcx().struct_warn_with_expectation(msg, id)
-    }
-    #[rustc_lint_diagnostics]
-    #[track_caller]
-    pub fn struct_span_allow<S: Into<MultiSpan>>(
-        &self,
-        sp: S,
-        msg: impl Into<DiagnosticMessage>,
-    ) -> DiagnosticBuilder<'_, ()> {
-        self.dcx().struct_span_allow(sp, msg)
-    }
-    #[rustc_lint_diagnostics]
-    #[track_caller]
     pub fn struct_allow(&self, msg: impl Into<DiagnosticMessage>) -> DiagnosticBuilder<'_, ()> {
         self.dcx().struct_allow(msg)
     }