Rollup merge of #111571 - jhpratt:proc-macro-span, r=m-ou-se

Implement proposed API for `proc_macro_span`

As proposed in [#54725 (comment)](rust-lang/rust#54725 (comment)). I have omitted the byte-level API as it's already available as [`Span::byte_range`](https://doc.rust-lang.org/nightly/proc_macro/struct.Span.html#method.byte_range).

`@rustbot` label +A-proc-macros

r? `@m-ou-se`

Author: Dylan-DPC

proc_macro/src/bridge/mod.rs

@@ -8,7 +8,7 @@
 
 #![deny(unsafe_code)]
 
-use crate::{Delimiter, Level, LineColumn, Spacing};
+use crate::{Delimiter, Level, Spacing};
 use std::fmt;
 use std::hash::Hash;
 use std::marker;
@@ -95,10 +95,10 @@ macro_rules! with_api {
                 fn parent($self: $S::Span) -> Option<$S::Span>;
                 fn source($self: $S::Span) -> $S::Span;
                 fn byte_range($self: $S::Span) -> Range<usize>;
-                fn start($self: $S::Span) -> LineColumn;
-                fn end($self: $S::Span) -> LineColumn;
-                fn before($self: $S::Span) -> $S::Span;
-                fn after($self: $S::Span) -> $S::Span;
+                fn start($self: $S::Span) -> $S::Span;
+                fn end($self: $S::Span) -> $S::Span;
+                fn line($self: $S::Span) -> usize;
+                fn column($self: $S::Span) -> usize;
                 fn join($self: $S::Span, other: $S::Span) -> Option<$S::Span>;
                 fn subspan($self: $S::Span, start: Bound<usize>, end: Bound<usize>) -> Option<$S::Span>;
                 fn resolved_at($self: $S::Span, at: $S::Span) -> $S::Span;
@@ -299,7 +299,6 @@ mark_noop! {
     Delimiter,
     LitKind,
     Level,
-    LineColumn,
     Spacing,
 }
 
@@ -319,7 +318,6 @@ rpc_encode_decode!(
         Help,
     }
 );
-rpc_encode_decode!(struct LineColumn { line, column });
 rpc_encode_decode!(
     enum Spacing {
         Alone,

proc_macro/src/lib.rs

@@ -43,7 +43,6 @@ mod diagnostic;
 #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
 pub use diagnostic::{Diagnostic, Level, MultiSpan};
 
-use std::cmp::Ordering;
 use std::ops::{Range, RangeBounds};
 use std::path::PathBuf;
 use std::str::FromStr;
@@ -494,28 +493,32 @@ impl Span {
         self.0.byte_range()
     }
 
-    /// Gets the starting line/column in the source file for this span.
+    /// Creates an empty span pointing to directly before this span.
     #[unstable(feature = "proc_macro_span", issue = "54725")]
-    pub fn start(&self) -> LineColumn {
-        self.0.start().add_1_to_column()
+    pub fn start(&self) -> Span {
+        Span(self.0.start())
     }
 
-    /// Gets the ending line/column in the source file for this span.
+    /// Creates an empty span pointing to directly after this span.
     #[unstable(feature = "proc_macro_span", issue = "54725")]
-    pub fn end(&self) -> LineColumn {
-        self.0.end().add_1_to_column()
+    pub fn end(&self) -> Span {
+        Span(self.0.end())
     }
 
-    /// Creates an empty span pointing to directly before this span.
-    #[unstable(feature = "proc_macro_span_shrink", issue = "87552")]
-    pub fn before(&self) -> Span {
-        Span(self.0.before())
+    /// The one-indexed line of the source file where the span starts.
+    ///
+    /// To obtain the line of the span's end, use `span.end().line()`.
+    #[unstable(feature = "proc_macro_span", issue = "54725")]
+    pub fn line(&self) -> usize {
+        self.0.line()
     }
 
-    /// Creates an empty span pointing to directly after this span.
-    #[unstable(feature = "proc_macro_span_shrink", issue = "87552")]
-    pub fn after(&self) -> Span {
-        Span(self.0.after())
+    /// The one-indexed column of the source file where the span starts.
+    ///
+    /// To obtain the column of the span's end, use `span.end().column()`.
+    #[unstable(feature = "proc_macro_span", issue = "54725")]
+    pub fn column(&self) -> usize {
+        self.0.column()
     }
 
     /// Creates a new span encompassing `self` and `other`.
@@ -586,44 +589,6 @@ impl fmt::Debug for Span {
     }
 }
 
-/// A line-column pair representing the start or end of a `Span`.
-#[unstable(feature = "proc_macro_span", issue = "54725")]
-#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
-pub struct LineColumn {
-    /// The 1-indexed line in the source file on which the span starts or ends (inclusive).
-    #[unstable(feature = "proc_macro_span", issue = "54725")]
-    pub line: usize,
-    /// The 1-indexed column (number of bytes in UTF-8 encoding) in the source
-    /// file on which the span starts or ends (inclusive).
-    #[unstable(feature = "proc_macro_span", issue = "54725")]
-    pub column: usize,
-}
-
-impl LineColumn {
-    fn add_1_to_column(self) -> Self {
-        LineColumn { line: self.line, column: self.column + 1 }
-    }
-}
-
-#[unstable(feature = "proc_macro_span", issue = "54725")]
-impl !Send for LineColumn {}
-#[unstable(feature = "proc_macro_span", issue = "54725")]
-impl !Sync for LineColumn {}
-
-#[unstable(feature = "proc_macro_span", issue = "54725")]
-impl Ord for LineColumn {
-    fn cmp(&self, other: &Self) -> Ordering {
-        self.line.cmp(&other.line).then(self.column.cmp(&other.column))
-    }
-}
-
-#[unstable(feature = "proc_macro_span", issue = "54725")]
-impl PartialOrd for LineColumn {
-    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
-        Some(self.cmp(other))
-    }
-}
-
 /// The source file of a given `Span`.
 #[unstable(feature = "proc_macro_span", issue = "54725")]
 #[derive(Clone)]