Moved the Diverges struct to its own file

Author: Nicholas-Baron

compiler/rustc_typeck/src/check/diverges.rs

@@ -0,0 +1,78 @@
+use rustc_span::source_map::DUMMY_SP;
+use rustc_span::{self, Span};
+use std::{cmp, ops};
+
+/// Tracks whether executing a node may exit normally (versus
+/// return/break/panic, which "diverge", leaving dead code in their
+/// wake). Tracked semi-automatically (through type variables marked
+/// as diverging), with some manual adjustments for control-flow
+/// primitives (approximating a CFG).
+#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
+pub enum Diverges {
+    /// Potentially unknown, some cases converge,
+    /// others require a CFG to determine them.
+    Maybe,
+
+    /// Definitely known to diverge and therefore
+    /// not reach the next sibling or its parent.
+    Always {
+        /// The `Span` points to the expression
+        /// that caused us to diverge
+        /// (e.g. `return`, `break`, etc).
+        span: Span,
+        /// In some cases (e.g. a `match` expression
+        /// where all arms diverge), we may be
+        /// able to provide a more informative
+        /// message to the user.
+        /// If this is `None`, a default message
+        /// will be generated, which is suitable
+        /// for most cases.
+        custom_note: Option<&'static str>,
+    },
+
+    /// Same as `Always` but with a reachability
+    /// warning already emitted.
+    WarnedAlways,
+}
+
+// Convenience impls for combining `Diverges`.
+
+impl ops::BitAnd for Diverges {
+    type Output = Self;
+    fn bitand(self, other: Self) -> Self {
+        cmp::min(self, other)
+    }
+}
+
+impl ops::BitOr for Diverges {
+    type Output = Self;
+    fn bitor(self, other: Self) -> Self {
+        cmp::max(self, other)
+    }
+}
+
+impl ops::BitAndAssign for Diverges {
+    fn bitand_assign(&mut self, other: Self) {
+        *self = *self & other;
+    }
+}
+
+impl ops::BitOrAssign for Diverges {
+    fn bitor_assign(&mut self, other: Self) {
+        *self = *self | other;
+    }
+}
+
+impl Diverges {
+    /// Creates a `Diverges::Always` with the provided `span` and the default note message.
+    pub(super) fn always(span: Span) -> Diverges {
+        Diverges::Always { span, custom_note: None }
+    }
+
+    pub(super) fn is_always(self) -> bool {
+        // Enum comparison ignores the
+        // contents of fields, so we just
+        // fill them in with garbage here.
+        self >= Diverges::Always { span: DUMMY_SP, custom_note: None }
+    }
+}

compiler/rustc_typeck/src/check/mod.rs

@@ -70,6 +70,7 @@ mod closure;
 pub mod coercion;
 mod compare_method;
 pub mod demand;
+mod diverges;
 pub mod dropck;
 mod expr;
 mod fn_ctxt;
@@ -86,6 +87,7 @@ mod upvar;
 mod wfcheck;
 pub mod writeback;
 
+pub use diverges::Diverges;
 pub use fn_ctxt::FnCtxt;
 pub use inherited::{Inherited, InheritedBuilder};
 
@@ -125,8 +127,6 @@ use rustc_trait_selection::traits::error_reporting::suggestions::ReturnsVisitor;
 use rustc_trait_selection::traits::{self, ObligationCauseCode};
 
 use std::cell::{Ref, RefCell, RefMut};
-use std::cmp;
-use std::ops::{self};
 
 use crate::require_c_abi_if_c_variadic;
 use crate::util::common::indenter;
@@ -326,81 +326,6 @@ pub enum PlaceOp {
     Index,
 }
 
-/// Tracks whether executing a node may exit normally (versus
-/// return/break/panic, which "diverge", leaving dead code in their
-/// wake). Tracked semi-automatically (through type variables marked
-/// as diverging), with some manual adjustments for control-flow
-/// primitives (approximating a CFG).
-#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
-pub enum Diverges {
-    /// Potentially unknown, some cases converge,
-    /// others require a CFG to determine them.
-    Maybe,
-
-    /// Definitely known to diverge and therefore
-    /// not reach the next sibling or its parent.
-    Always {
-        /// The `Span` points to the expression
-        /// that caused us to diverge
-        /// (e.g. `return`, `break`, etc).
-        span: Span,
-        /// In some cases (e.g. a `match` expression
-        /// where all arms diverge), we may be
-        /// able to provide a more informative
-        /// message to the user.
-        /// If this is `None`, a default message
-        /// will be generated, which is suitable
-        /// for most cases.
-        custom_note: Option<&'static str>,
-    },
-
-    /// Same as `Always` but with a reachability
-    /// warning already emitted.
-    WarnedAlways,
-}
-
-// Convenience impls for combining `Diverges`.
-
-impl ops::BitAnd for Diverges {
-    type Output = Self;
-    fn bitand(self, other: Self) -> Self {
-        cmp::min(self, other)
-    }
-}
-
-impl ops::BitOr for Diverges {
-    type Output = Self;
-    fn bitor(self, other: Self) -> Self {
-        cmp::max(self, other)
-    }
-}
-
-impl ops::BitAndAssign for Diverges {
-    fn bitand_assign(&mut self, other: Self) {
-        *self = *self & other;
-    }
-}
-
-impl ops::BitOrAssign for Diverges {
-    fn bitor_assign(&mut self, other: Self) {
-        *self = *self | other;
-    }
-}
-
-impl Diverges {
-    /// Creates a `Diverges::Always` with the provided `span` and the default note message.
-    fn always(span: Span) -> Diverges {
-        Diverges::Always { span, custom_note: None }
-    }
-
-    fn is_always(self) -> bool {
-        // Enum comparison ignores the
-        // contents of fields, so we just
-        // fill them in with garbage here.
-        self >= Diverges::Always { span: DUMMY_SP, custom_note: None }
-    }
-}
-
 pub struct BreakableCtxt<'tcx> {
     may_break: bool,