Auto merge of #50454 - Manishearth:edition-preview-fixes, r=alexcrichton

Various edition preview fixes

Implement a bunch of things discussed in the meeting.

src/test/compile-fail/rfc-2126-extern-absolute-paths/non-existent-1.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// compile-flags: --edition=2018 -Zunstable-options
+
 #![feature(extern_absolute_paths)]
 
 use xcrate::S; //~ ERROR can't find crate for `xcrate`

src/test/compile-fail/rfc-2126-extern-absolute-paths/non-existent-2.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// compile-flags: --edition=2018 -Zunstable-options
+
 #![feature(extern_absolute_paths)]
 
 fn main() {

src/test/compile-fail/rfc-2126-extern-absolute-paths/non-existent-3.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// compile-flags: --edition=2018 -Zunstable-options
+
 #![feature(extern_absolute_paths)]
 
 use ycrate; //~ ERROR can't find crate for `ycrate`

src/test/compile-fail/rfc-2126-extern-absolute-paths/single-segment.rs

@@ -9,6 +9,7 @@
 // except according to those terms.
 
 // aux-build:xcrate.rs
+// compile-flags: --edition=2018 -Zunstable-options
 
 #![feature(crate_in_paths)]
 #![feature(extern_absolute_paths)]

src/test/run-make-fulldeps/save-analysis-rfc2126/Makefile

@@ -1,9 +1,9 @@
 -include ../tools.mk
 
 all: extern_absolute_paths.rs extern_in_paths.rs krate2
-	$(RUSTC) extern_absolute_paths.rs -Zsave-analysis
+	$(RUSTC) extern_absolute_paths.rs -Zsave-analysis --edition=2018
 	cat $(TMPDIR)/save-analysis/extern_absolute_paths.json | "$(PYTHON)" validate_json.py
-	$(RUSTC) extern_in_paths.rs -Zsave-analysis
+	$(RUSTC) extern_in_paths.rs -Zsave-analysis --edition=2018
 	cat $(TMPDIR)/save-analysis/extern_in_paths.json | "$(PYTHON)" validate_json.py
 
 krate2: krate2.rs

src/test/run-pass/rfc-2126-extern-absolute-paths/basic.rs

@@ -9,6 +9,7 @@
 // except according to those terms.
 
 // aux-build:xcrate.rs
+// compile-flags: --edition=2018 -Zunstable-options
 
 #![feature(extern_absolute_paths)]
 

src/test/run-pass/rfc-2126-extern-absolute-paths/test.rs

@@ -12,7 +12,7 @@
 //
 // Regression test for #47075.
 
-// compile-flags: --test
+// compile-flags: --test --edition=2018 -Zunstable-options
 
 #![feature(extern_absolute_paths)]