Rollup merge of #99895 - compiler-errors:type-ascription-aint-cast, r=davidtwco

don't call type ascription "cast"

Noticed in #99885

Author: Dylan-DPC

compiler/rustc_parse/src/parser/expr.rs

@@ -827,11 +827,12 @@ impl<'a> Parser<'a> {
         cast_expr: P<Expr>,
     ) -> PResult<'a, P<Expr>> {
         let span = cast_expr.span;
-        let maybe_ascription_span = if let ExprKind::Type(ascripted_expr, _) = &cast_expr.kind {
-            Some(ascripted_expr.span.shrink_to_hi().with_hi(span.hi()))
-        } else {
-            None
-        };
+        let (cast_kind, maybe_ascription_span) =
+            if let ExprKind::Type(ascripted_expr, _) = &cast_expr.kind {
+                ("type ascription", Some(ascripted_expr.span.shrink_to_hi().with_hi(span.hi())))
+            } else {
+                ("cast", None)
+            };
 
         // Save the memory location of expr before parsing any following postfix operators.
         // This will be compared with the memory location of the output expression.
@@ -844,7 +845,7 @@ impl<'a> Parser<'a> {
         // If the resulting expression is not a cast, or has a different memory location, it is an illegal postfix operator.
         if !matches!(with_postfix.kind, ExprKind::Cast(_, _) | ExprKind::Type(_, _)) || changed {
             let msg = format!(
-                "casts cannot be followed by {}",
+                "{cast_kind} cannot be followed by {}",
                 match with_postfix.kind {
                     ExprKind::Index(_, _) => "indexing",
                     ExprKind::Try(_) => "`?`",

src/test/ui/parser/issues/issue-35813-postfix-after-cast.rs

@@ -8,16 +8,16 @@ use std::pin::Pin;
 // errors and parse such that further code gives useful errors.
 pub fn index_after_as_cast() {
     vec![1, 2, 3] as Vec<i32>[0];
-    //~^ ERROR: casts cannot be followed by indexing
+    //~^ ERROR: cast cannot be followed by indexing
     vec![1, 2, 3]: Vec<i32>[0];
-    //~^ ERROR: casts cannot be followed by indexing
+    //~^ ERROR: type ascription cannot be followed by indexing
 }
 
 pub fn index_after_cast_to_index() {
     (&[0]) as &[i32][0];
-    //~^ ERROR: casts cannot be followed by indexing
+    //~^ ERROR: cast cannot be followed by indexing
     (&[0i32]): &[i32; 1][0];
-    //~^ ERROR: casts cannot be followed by indexing
+    //~^ ERROR: type ascription cannot be followed by indexing
 }
 
 pub fn cast_after_cast() {
@@ -37,89 +37,89 @@ pub fn cast_after_cast() {
 
 pub fn cast_cast_method_call() {
     let _ = 0i32: i32: i32.count_ones();
-    //~^ ERROR: casts cannot be followed by a method call
+    //~^ ERROR: type ascription cannot be followed by a method call
     let _ = 0 as i32: i32.count_ones();
-    //~^ ERROR: casts cannot be followed by a method call
+    //~^ ERROR: type ascription cannot be followed by a method call
     let _ = 0i32: i32 as i32.count_ones();
-    //~^ ERROR: casts cannot be followed by a method call
+    //~^ ERROR: cast cannot be followed by a method call
     let _ = 0 as i32 as i32.count_ones();
-    //~^ ERROR: casts cannot be followed by a method call
+    //~^ ERROR: cast cannot be followed by a method call
     let _ = 0i32: i32: i32 as u32 as i32.count_ones();
-    //~^ ERROR: casts cannot be followed by a method call
+    //~^ ERROR: cast cannot be followed by a method call
     let _ = 0i32: i32.count_ones(): u32;
-    //~^ ERROR: casts cannot be followed by a method call
+    //~^ ERROR: type ascription cannot be followed by a method call
     let _ = 0 as i32.count_ones(): u32;
-    //~^ ERROR: casts cannot be followed by a method call
+    //~^ ERROR: cast cannot be followed by a method call
     let _ = 0i32: i32.count_ones() as u32;
-    //~^ ERROR: casts cannot be followed by a method call
+    //~^ ERROR: type ascription cannot be followed by a method call
     let _ = 0 as i32.count_ones() as u32;
-    //~^ ERROR: casts cannot be followed by a method call
+    //~^ ERROR: cast cannot be followed by a method call
     let _ = 0i32: i32: i32.count_ones() as u32 as i32;
-    //~^ ERROR: casts cannot be followed by a method call
+    //~^ ERROR: type ascription cannot be followed by a method call
 }
 
 pub fn multiline_error() {
     let _ = 0
         as i32
         .count_ones();
-    //~^^^ ERROR: casts cannot be followed by a method call
+    //~^^^ ERROR: cast cannot be followed by a method call
 }
 
 // this tests that the precedence for `!x as Y.Z` is still what we expect
 pub fn precedence() {
     let x: i32 = &vec![1, 2, 3] as &Vec<i32>[0];
-    //~^ ERROR: casts cannot be followed by indexing
+    //~^ ERROR: cast cannot be followed by indexing
 }
 
 pub fn method_calls() {
     0 as i32.max(0);
-    //~^ ERROR: casts cannot be followed by a method call
+    //~^ ERROR: cast cannot be followed by a method call
     0: i32.max(0);
-    //~^ ERROR: casts cannot be followed by a method call
+    //~^ ERROR: type ascription cannot be followed by a method call
 }
 
 pub fn complex() {
     let _ = format!(
         "{} and {}",
         if true { 33 } else { 44 } as i32.max(0),
-        //~^ ERROR: casts cannot be followed by a method call
+        //~^ ERROR: cast cannot be followed by a method call
         if true { 33 } else { 44 }: i32.max(0)
-        //~^ ERROR: casts cannot be followed by a method call
+        //~^ ERROR: type ascription cannot be followed by a method call
     );
 }
 
 pub fn in_condition() {
     if 5u64 as i32.max(0) == 0 {
-        //~^ ERROR: casts cannot be followed by a method call
+        //~^ ERROR: cast cannot be followed by a method call
     }
     if 5u64: u64.max(0) == 0 {
-        //~^ ERROR: casts cannot be followed by a method call
+        //~^ ERROR: type ascription cannot be followed by a method call
     }
 }
 
 pub fn inside_block() {
     let _ = if true {
         5u64 as u32.max(0) == 0
-        //~^ ERROR: casts cannot be followed by a method call
+        //~^ ERROR: cast cannot be followed by a method call
     } else { false };
     let _ = if true {
         5u64: u64.max(0) == 0
-        //~^ ERROR: casts cannot be followed by a method call
+        //~^ ERROR: type ascription cannot be followed by a method call
     } else { false };
 }
 
 static bar: &[i32] = &(&[1,2,3] as &[i32][0..1]);
-//~^ ERROR: casts cannot be followed by indexing
+//~^ ERROR: cast cannot be followed by indexing
 
 static bar2: &[i32] = &(&[1i32,2,3]: &[i32; 3][0..1]);
-//~^ ERROR: casts cannot be followed by indexing
+//~^ ERROR: type ascription cannot be followed by indexing
 
 
 pub fn cast_then_try() -> Result<u64,u64> {
     Err(0u64) as Result<u64,u64>?;
-    //~^ ERROR: casts cannot be followed by `?`
+    //~^ ERROR: cast cannot be followed by `?`
     Err(0u64): Result<u64,u64>?;
-    //~^ ERROR: casts cannot be followed by `?`
+    //~^ ERROR: type ascription cannot be followed by `?`
     Ok(1)
 }
 
@@ -143,17 +143,17 @@ pub fn cast_to_fn_should_work() {
 pub fn parens_after_cast_error() {
     let drop_ptr = drop as fn(u8);
     drop as fn(u8)(0);
-    //~^ ERROR: casts cannot be followed by a function call
+    //~^ ERROR: cast cannot be followed by a function call
     drop_ptr: fn(u8)(0);
-    //~^ ERROR: casts cannot be followed by a function call
+    //~^ ERROR: type ascription cannot be followed by a function call
 }
 
 pub async fn cast_then_await() {
     Box::pin(noop()) as Pin<Box<dyn Future<Output = ()>>>.await;
-    //~^ ERROR: casts cannot be followed by `.await`
+    //~^ ERROR: cast cannot be followed by `.await`
 
     Box::pin(noop()): Pin<Box<_>>.await;
-    //~^ ERROR: casts cannot be followed by `.await`
+    //~^ ERROR: type ascription cannot be followed by `.await`
 }
 
 pub async fn noop() {}
@@ -167,5 +167,5 @@ pub fn struct_field() {
     Foo::default() as Foo.bar;
     //~^ ERROR: cannot be followed by a field access
     Foo::default(): Foo.bar;
-    //~^ ERROR: cannot be followed by a field access
+    //~^ ERROR: type ascription cannot be followed by a field access
 }