Rollup merge of rust-lang#139294 - beetrees:fix-f16-f128-literal-feature-gate, r=fmease

Fix the `f16`/`f128` feature gates on integer literals

The feature gating logic for `f16`/`f128` currently only checks float literals, meaning this code currently compiles with no feature gates on stable ([playground](https://play.rust-lang.org/?version=stable&mode=debug&edition=2024&gist=b0c0e285ccb822fc7e2abc595557886b)):
```rust
fn main() {
    let a = 1f16;
    let b = 1f128;
    dbg!(a, b);
}
```
This PR fixes that.

Tracking issue: rust-lang#116909

Author: matthiaskrgr

Diff for: compiler/rustc_ast_passes/src/feature_gate.rs

@@ -332,17 +332,19 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
             ast::ExprKind::TryBlock(_) => {
                 gate!(&self, try_blocks, e.span, "`try` expression is experimental");
             }
-            ast::ExprKind::Lit(token::Lit { kind: token::LitKind::Float, suffix, .. }) => {
-                match suffix {
-                    Some(sym::f16) => {
-                        gate!(&self, f16, e.span, "the type `f16` is unstable")
-                    }
-                    Some(sym::f128) => {
-                        gate!(&self, f128, e.span, "the type `f128` is unstable")
-                    }
-                    _ => (),
+            ast::ExprKind::Lit(token::Lit {
+                kind: token::LitKind::Float | token::LitKind::Integer,
+                suffix,
+                ..
+            }) => match suffix {
+                Some(sym::f16) => {
+                    gate!(&self, f16, e.span, "the type `f16` is unstable")
                 }
-            }
+                Some(sym::f128) => {
+                    gate!(&self, f128, e.span, "the type `f128` is unstable")
+                }
+                _ => (),
+            },
             _ => {}
         }
         visit::walk_expr(self, e)

Diff for: tests/ui/feature-gates/feature-gate-f128.e2015.stderr

@@ -19,7 +19,7 @@ LL |     let a: f128 = 100.0;
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
 error[E0658]: the type `f128` is unstable
-  --> $DIR/feature-gate-f128.rs:15:11
+  --> $DIR/feature-gate-f128.rs:16:11
    |
 LL | fn foo(a: f128) {}
    |           ^^^^
@@ -29,7 +29,7 @@ LL | fn foo(a: f128) {}
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
 error[E0658]: the type `f128` is unstable
-  --> $DIR/feature-gate-f128.rs:18:8
+  --> $DIR/feature-gate-f128.rs:19:8
    |
 LL |     a: f128,
    |        ^^^^
@@ -48,6 +48,16 @@ LL |     let b = 0.0f128;
    = help: add `#![feature(f128)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error: aborting due to 5 previous errors
+error[E0658]: the type `f128` is unstable
+  --> $DIR/feature-gate-f128.rs:12:13
+   |
+LL |     let c = 0f128;
+   |             ^^^^^
+   |
+   = note: see issue #116909 <https://github.com/rust-lang/rust/issues/116909> for more information
+   = help: add `#![feature(f128)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error: aborting due to 6 previous errors
 
 For more information about this error, try `rustc --explain E0658`.

Diff for: tests/ui/feature-gates/feature-gate-f128.e2018.stderr

@@ -19,7 +19,7 @@ LL |     let a: f128 = 100.0;
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
 error[E0658]: the type `f128` is unstable
-  --> $DIR/feature-gate-f128.rs:15:11
+  --> $DIR/feature-gate-f128.rs:16:11
    |
 LL | fn foo(a: f128) {}
    |           ^^^^
@@ -29,7 +29,7 @@ LL | fn foo(a: f128) {}
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
 error[E0658]: the type `f128` is unstable
-  --> $DIR/feature-gate-f128.rs:18:8
+  --> $DIR/feature-gate-f128.rs:19:8
    |
 LL |     a: f128,
    |        ^^^^
@@ -48,6 +48,16 @@ LL |     let b = 0.0f128;
    = help: add `#![feature(f128)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error: aborting due to 5 previous errors
+error[E0658]: the type `f128` is unstable
+  --> $DIR/feature-gate-f128.rs:12:13
+   |
+LL |     let c = 0f128;
+   |             ^^^^^
+   |
+   = note: see issue #116909 <https://github.com/rust-lang/rust/issues/116909> for more information
+   = help: add `#![feature(f128)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error: aborting due to 6 previous errors
 
 For more information about this error, try `rustc --explain E0658`.

Diff for: tests/ui/feature-gates/feature-gate-f128.rs

@@ -9,6 +9,7 @@ const A: f128 = 10.0; //~ ERROR the type `f128` is unstable
 pub fn main() {
     let a: f128 = 100.0; //~ ERROR the type `f128` is unstable
     let b = 0.0f128; //~ ERROR the type `f128` is unstable
+    let c = 0f128; //~ ERROR the type `f128` is unstable
     foo(1.23);
 }
 

Diff for: tests/ui/feature-gates/feature-gate-f16.e2015.stderr

@@ -19,7 +19,7 @@ LL |     let a: f16 = 100.0;
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
 error[E0658]: the type `f16` is unstable
-  --> $DIR/feature-gate-f16.rs:15:11
+  --> $DIR/feature-gate-f16.rs:16:11
    |
 LL | fn foo(a: f16) {}
    |           ^^^
@@ -29,7 +29,7 @@ LL | fn foo(a: f16) {}
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
 error[E0658]: the type `f16` is unstable
-  --> $DIR/feature-gate-f16.rs:18:8
+  --> $DIR/feature-gate-f16.rs:19:8
    |
 LL |     a: f16,
    |        ^^^
@@ -48,6 +48,16 @@ LL |     let b = 0.0f16;
    = help: add `#![feature(f16)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error: aborting due to 5 previous errors
+error[E0658]: the type `f16` is unstable
+  --> $DIR/feature-gate-f16.rs:12:13
+   |
+LL |     let c = 0f16;
+   |             ^^^^
+   |
+   = note: see issue #116909 <https://github.com/rust-lang/rust/issues/116909> for more information
+   = help: add `#![feature(f16)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error: aborting due to 6 previous errors
 
 For more information about this error, try `rustc --explain E0658`.

Diff for: tests/ui/feature-gates/feature-gate-f16.e2018.stderr

@@ -19,7 +19,7 @@ LL |     let a: f16 = 100.0;
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
 error[E0658]: the type `f16` is unstable
-  --> $DIR/feature-gate-f16.rs:15:11
+  --> $DIR/feature-gate-f16.rs:16:11
    |
 LL | fn foo(a: f16) {}
    |           ^^^
@@ -29,7 +29,7 @@ LL | fn foo(a: f16) {}
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
 error[E0658]: the type `f16` is unstable
-  --> $DIR/feature-gate-f16.rs:18:8
+  --> $DIR/feature-gate-f16.rs:19:8
    |
 LL |     a: f16,
    |        ^^^
@@ -48,6 +48,16 @@ LL |     let b = 0.0f16;
    = help: add `#![feature(f16)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error: aborting due to 5 previous errors
+error[E0658]: the type `f16` is unstable
+  --> $DIR/feature-gate-f16.rs:12:13
+   |
+LL |     let c = 0f16;
+   |             ^^^^
+   |
+   = note: see issue #116909 <https://github.com/rust-lang/rust/issues/116909> for more information
+   = help: add `#![feature(f16)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error: aborting due to 6 previous errors
 
 For more information about this error, try `rustc --explain E0658`.

Diff for: tests/ui/feature-gates/feature-gate-f16.rs

@@ -9,6 +9,7 @@ const A: f16 = 10.0; //~ ERROR the type `f16` is unstable
 pub fn main() {
     let a: f16 = 100.0; //~ ERROR the type `f16` is unstable
     let b = 0.0f16; //~ ERROR the type `f16` is unstable
+    let c = 0f16; //~ ERROR the type `f16` is unstable
     foo(1.23);
 }