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Auto merge of #47099 - SergioBenitez:master, r=jseyfried
Add 'Span::parent()' and 'Span::source()' to proc_macro API. As the title suggests: a couple of useful methods for `proc_macro`.
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Diff for: ‎src/libproc_macro/lib.rs

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@@ -221,6 +221,21 @@ impl Span {
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}
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}
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/// The `Span` for the tokens in the previous macro expansion from which
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/// `self` was generated from, if any.
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#[unstable(feature = "proc_macro", issue = "38356")]
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pub fn parent(&self) -> Option<Span> {
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self.0.ctxt().outer().expn_info().map(|i| Span(i.call_site))
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}
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/// The span for the origin source code that `self` was generated from. If
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/// this `Span` wasn't generated from other macro expansions then the return
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/// value is the same as `*self`.
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#[unstable(feature = "proc_macro", issue = "38356")]
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pub fn source(&self) -> Span {
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Span(self.0.source_callsite())
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}
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/// Get the starting line/column in the source file for this span.
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#[unstable(feature = "proc_macro", issue = "38356")]
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pub fn start(&self) -> LineColumn {

Diff for: ‎src/test/ui-fulldeps/proc-macro/auxiliary/parent-source-spans.rs

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@@ -0,0 +1,51 @@
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// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// no-prefer-dynamic
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#![feature(proc_macro)]
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#![crate_type = "proc-macro"]
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extern crate proc_macro;
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use proc_macro::{TokenStream, TokenTree, TokenNode, Span};
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fn lit_span(tt: TokenTree) -> (Span, String) {
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use TokenNode::*;
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match tt.kind {
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Literal(..) | Group(..) => (tt.span, tt.to_string().trim().into()),
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_ => panic!("expected a literal in token tree, got: {:?}", tt)
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}
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}
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#[proc_macro]
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pub fn parent_source_spans(input: TokenStream) -> TokenStream {
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let mut tokens = input.into_iter();
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let (sp1, str1) = lit_span(tokens.next().expect("first string"));
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let _ = tokens.next();
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let (sp2, str2) = lit_span(tokens.next().expect("second string"));
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sp1.error(format!("first final: {}", str1)).emit();
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sp2.error(format!("second final: {}", str2)).emit();
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if let (Some(p1), Some(p2)) = (sp1.parent(), sp2.parent()) {
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p1.error(format!("first parent: {}", str1)).emit();
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p2.error(format!("second parent: {}", str2)).emit();
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if let (Some(gp1), Some(gp2)) = (p1.parent(), p2.parent()) {
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gp1.error(format!("first grandparent: {}", str1)).emit();
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gp2.error(format!("second grandparent: {}", str2)).emit();
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}
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}
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sp1.source().error(format!("first source: {}", str1)).emit();
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sp2.source().error(format!("second source: {}", str2)).emit();
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"ok".parse().unwrap()
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}

Diff for: ‎src/test/ui-fulldeps/proc-macro/parent-source-spans.rs

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// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// aux-build:parent-source-spans.rs
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// ignore-stage1
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#![feature(proc_macro, decl_macro)]
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extern crate parent_source_spans;
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use parent_source_spans::parent_source_spans;
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macro one($a:expr, $b:expr) {
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two!($a, $b);
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//~^ ERROR first parent: "hello"
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//~| ERROR second parent: "world"
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}
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macro two($a:expr, $b:expr) {
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three!($a, $b);
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//~^ ERROR first final: "hello"
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//~| ERROR second final: "world"
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//~| ERROR first final: "yay"
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//~| ERROR second final: "rust"
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}
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// forwarding tokens directly doesn't create a new source chain
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macro three($($tokens:tt)*) {
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four!($($tokens)*);
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}
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macro four($($tokens:tt)*) {
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parent_source_spans!($($tokens)*);
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}
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fn main() {
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one!("hello", "world");
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//~^ ERROR first grandparent: "hello"
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//~| ERROR second grandparent: "world"
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//~| ERROR first source: "hello"
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//~| ERROR second source: "world"
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two!("yay", "rust");
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//~^ ERROR first parent: "yay"
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//~| ERROR second parent: "rust"
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//~| ERROR first source: "yay"
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//~| ERROR second source: "rust"
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three!("hip", "hop");
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//~^ ERROR first final: "hip"
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//~| ERROR second final: "hop"
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//~| ERROR first source: "hip"
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//~| ERROR second source: "hop"
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}

Diff for: ‎src/test/ui-fulldeps/proc-macro/parent-source-spans.stderr

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error: first final: "hello"
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--> $DIR/parent-source-spans.rs:27:12
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|
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27 | three!($a, $b);
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| ^^
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...
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44 | one!("hello", "world");
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| ----------------------- in this macro invocation
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error: second final: "world"
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--> $DIR/parent-source-spans.rs:27:16
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|
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27 | three!($a, $b);
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| ^^
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...
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44 | one!("hello", "world");
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| ----------------------- in this macro invocation
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error: first parent: "hello"
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--> $DIR/parent-source-spans.rs:21:5
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|
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21 | two!($a, $b);
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| ^^^^^^^^^^^^^
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...
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44 | one!("hello", "world");
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| ----------------------- in this macro invocation
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error: second parent: "world"
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--> $DIR/parent-source-spans.rs:21:5
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|
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21 | two!($a, $b);
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| ^^^^^^^^^^^^^
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...
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44 | one!("hello", "world");
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| ----------------------- in this macro invocation
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error: first grandparent: "hello"
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--> $DIR/parent-source-spans.rs:44:5
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|
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44 | one!("hello", "world");
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| ^^^^^^^^^^^^^^^^^^^^^^^
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error: second grandparent: "world"
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--> $DIR/parent-source-spans.rs:44:5
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|
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44 | one!("hello", "world");
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| ^^^^^^^^^^^^^^^^^^^^^^^
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error: first source: "hello"
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--> $DIR/parent-source-spans.rs:44:5
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|
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44 | one!("hello", "world");
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| ^^^^^^^^^^^^^^^^^^^^^^^
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error: second source: "world"
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--> $DIR/parent-source-spans.rs:44:5
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|
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44 | one!("hello", "world");
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| ^^^^^^^^^^^^^^^^^^^^^^^
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error: first final: "yay"
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--> $DIR/parent-source-spans.rs:27:12
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|
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27 | three!($a, $b);
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| ^^
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...
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50 | two!("yay", "rust");
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| -------------------- in this macro invocation
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error: second final: "rust"
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--> $DIR/parent-source-spans.rs:27:16
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|
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27 | three!($a, $b);
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| ^^
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...
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50 | two!("yay", "rust");
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| -------------------- in this macro invocation
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error: first parent: "yay"
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--> $DIR/parent-source-spans.rs:50:5
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|
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50 | two!("yay", "rust");
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| ^^^^^^^^^^^^^^^^^^^^
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error: second parent: "rust"
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--> $DIR/parent-source-spans.rs:50:5
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|
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50 | two!("yay", "rust");
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| ^^^^^^^^^^^^^^^^^^^^
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error: first source: "yay"
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--> $DIR/parent-source-spans.rs:50:5
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|
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50 | two!("yay", "rust");
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| ^^^^^^^^^^^^^^^^^^^^
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error: second source: "rust"
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--> $DIR/parent-source-spans.rs:50:5
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|
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50 | two!("yay", "rust");
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| ^^^^^^^^^^^^^^^^^^^^
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error: first final: "hip"
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--> $DIR/parent-source-spans.rs:56:12
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|
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56 | three!("hip", "hop");
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| ^^^^^
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error: second final: "hop"
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--> $DIR/parent-source-spans.rs:56:19
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|
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56 | three!("hip", "hop");
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| ^^^^^
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error: first source: "hip"
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--> $DIR/parent-source-spans.rs:56:12
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|
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56 | three!("hip", "hop");
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| ^^^^^
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error: second source: "hop"
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--> $DIR/parent-source-spans.rs:56:19
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|
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56 | three!("hip", "hop");
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| ^^^^^
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error: aborting due to 18 previous errors
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