New ui tests for new soft feature gates

src/test/ui/feature-gates/soft-syntax-gates-with-errors.rs

@@ -0,0 +1,30 @@
+// check-fail
+// This file is used to test the behavior of the early-pass syntax warnings.
+// If macro syntax is stabilized, replace with a different unstable syntax.
+
+macro a() {}
+//~^ ERROR: `macro` is experimental
+
+#[cfg(FALSE)]
+macro b() {}
+
+macro_rules! identity {
+    ($($x:tt)*) => ($($x)*);
+}
+
+identity! {
+    macro c() {}
+    //~^ ERROR: `macro` is experimental
+}
+
+#[cfg(FALSE)]
+identity! {
+    macro d() {} // No error
+}
+
+identity! {
+    #[cfg(FALSE)]
+    macro e() {}
+}
+
+fn main() {}

src/test/ui/feature-gates/soft-syntax-gates-with-errors.stderr

@@ -0,0 +1,21 @@
+error[E0658]: `macro` is experimental
+  --> $DIR/soft-syntax-gates-with-errors.rs:5:1
+   |
+LL | macro a() {}
+   | ^^^^^^^^^^^^
+   |
+   = note: see issue #39412 <https://github.com/rust-lang/rust/issues/39412> for more information
+   = help: add `#![feature(decl_macro)]` to the crate attributes to enable
+
+error[E0658]: `macro` is experimental
+  --> $DIR/soft-syntax-gates-with-errors.rs:16:5
+   |
+LL |     macro c() {}
+   |     ^^^^^^^^^^^^
+   |
+   = note: see issue #39412 <https://github.com/rust-lang/rust/issues/39412> for more information
+   = help: add `#![feature(decl_macro)]` to the crate attributes to enable
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0658`.

src/test/ui/feature-gates/soft-syntax-gates-without-errors.rs

@@ -0,0 +1,26 @@
+// check-pass
+// This file is used to test the behavior of the early-pass syntax warnings.
+// If macro syntax is stabilized, replace with a different unstable syntax.
+
+#[cfg(FALSE)]
+macro b() {}
+//~^ WARN: `macro` is experimental
+//~| WARN: unstable syntax
+
+macro_rules! identity {
+    ($($x:tt)*) => ($($x)*);
+}
+
+#[cfg(FALSE)]
+identity! {
+    macro d() {} // No error
+}
+
+identity! {
+    #[cfg(FALSE)]
+    macro e() {}
+    //~^ WARN: `macro` is experimental
+    //~| WARN: unstable syntax
+}
+
+fn main() {}

src/test/ui/feature-gates/soft-syntax-gates-without-errors.stderr

@@ -0,0 +1,24 @@
+warning: `macro` is experimental
+  --> $DIR/soft-syntax-gates-without-errors.rs:6:1
+   |
+LL | macro b() {}
+   | ^^^^^^^^^^^^
+   |
+   = note: see issue #39412 <https://github.com/rust-lang/rust/issues/39412> for more information
+   = help: add `#![feature(decl_macro)]` to the crate attributes to enable
+   = warning: unstable syntax can change at any point in the future, causing a hard error!
+   = note: for more information, see issue #65860 <https://github.com/rust-lang/rust/issues/65860>
+
+warning: `macro` is experimental
+  --> $DIR/soft-syntax-gates-without-errors.rs:21:5
+   |
+LL |     macro e() {}
+   |     ^^^^^^^^^^^^
+   |
+   = note: see issue #39412 <https://github.com/rust-lang/rust/issues/39412> for more information
+   = help: add `#![feature(decl_macro)]` to the crate attributes to enable
+   = warning: unstable syntax can change at any point in the future, causing a hard error!
+   = note: for more information, see issue #65860 <https://github.com/rust-lang/rust/issues/65860>
+
+warning: 2 warnings emitted
+

src/test/ui/suggestions/many-type-ascription.rs

@@ -0,0 +1,4 @@
+fn main() {
+    let _ = 0: i32; //~ ERROR: type ascription is experimental
+    let _ = 0: i32; // (error only emitted once)
+}

src/test/ui/suggestions/many-type-ascription.stderr

@@ -0,0 +1,12 @@
+error[E0658]: type ascription is experimental
+  --> $DIR/many-type-ascription.rs:2:13
+   |
+LL |     let _ = 0: i32;
+   |             ^^^^^^
+   |
+   = note: see issue #23416 <https://github.com/rust-lang/rust/issues/23416> for more information
+   = help: add `#![feature(type_ascription)]` to the crate attributes to enable
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0658`.

src/test/ui/suggestions/type-ascription-and-other-error.rs

@@ -0,0 +1,6 @@
+fn main() {
+    not rust; //~ ERROR
+    let _ = 0: i32; // (error hidden by existing error)
+    #[cfg(FALSE)]
+    let _ = 0: i32; // (warning hidden by existing error)
+}

src/test/ui/suggestions/type-ascription-and-other-error.stderr

@@ -0,0 +1,8 @@
+error: expected one of `!`, `.`, `::`, `;`, `?`, `{`, `}`, or an operator, found `rust`
+  --> $DIR/type-ascription-and-other-error.rs:2:9
+   |
+LL |     not rust;
+   |         ^^^^ expected one of 8 possible tokens
+
+error: aborting due to previous error
+