Auto merge of #66994 - Centril:stmt-polish, r=estebank

refactor expr & stmt parsing + improve recovery

Summary of important changes (best read commit-by-commit, ignoring whitespace changes):

- `AttrVec` is introduces as an alias for `ThinVec<Attribute>`
- `parse_expr_bottom` and `parse_stmt` are thoroughly refactored.
- Extract diagnostics logic for `vec![...]` in a pattern context.
- Recovery is added for `do catch { ... }`
- Recovery is added for `'label: non_block_expr`
- Recovery is added for `var $local`, `auto $local`, and `mut $local`. Fixes #65257.
- Recovery is added for `e1 and e2` and `e1 or e2`.
- ~~`macro_legacy_warnings` is turned into an error (has been a warning for 3 years!)~~
- Fixes #63396 by forward-porting #64105 which now works thanks to added recovery.
- `ui-fulldeps/ast_stmt_expr_attr.rs` is turned into UI and pretty tests.
- Recovery is fixed for `#[attr] if expr {}`

r? @estebank

1 files changed, 107 insertions, 0 deletions

diff --git a/src/test/ui/parser/attr-stmt-expr-attr-bad.rs b/src/test/ui/parser/attr-stmt-expr-attr-bad.rs
new file mode 100644
index 00000000000..ef10010ed0e
--- /dev/null
+++ b/src/test/ui/parser/attr-stmt-expr-attr-bad.rs
@@ -0,0 +1,107 @@
+fn main() {}
+
+#[cfg(FALSE)] fn e() { let _ = box #![attr] 0; }
+//~^ ERROR an inner attribute is not permitted in this context
+#[cfg(FALSE)] fn e() { let _ = [#[attr]]; }
+//~^ ERROR expected expression, found `]`
+#[cfg(FALSE)] fn e() { let _ = foo#[attr](); }
+//~^ ERROR expected one of
+#[cfg(FALSE)] fn e() { let _ = foo(#![attr]); }
+//~^ ERROR an inner attribute is not permitted in this context
+//~| ERROR expected expression, found `)`
+#[cfg(FALSE)] fn e() { let _ = x.foo(#![attr]); }
+//~^ ERROR an inner attribute is not permitted in this context
+//~| ERROR expected expression, found `)`
+#[cfg(FALSE)] fn e() { let _ = 0 + #![attr] 0; }
+//~^ ERROR an inner attribute is not permitted in this context
+#[cfg(FALSE)] fn e() { let _ = !#![attr] 0; }
+//~^ ERROR an inner attribute is not permitted in this context
+#[cfg(FALSE)] fn e() { let _ = -#![attr] 0; }
+//~^ ERROR an inner attribute is not permitted in this context
+#[cfg(FALSE)] fn e() { let _ = x #![attr] as Y; }
+//~^ ERROR expected one of
+#[cfg(FALSE)] fn e() { let _ = || #![attr] foo; }
+//~^ ERROR an inner attribute is not permitted in this context
+#[cfg(FALSE)] fn e() { let _ = move || #![attr] foo; }
+//~^ ERROR an inner attribute is not permitted in this context
+#[cfg(FALSE)] fn e() { let _ = || #![attr] {foo}; }
+//~^ ERROR an inner attribute is not permitted in this context
+#[cfg(FALSE)] fn e() { let _ = move || #![attr] {foo}; }
+//~^ ERROR an inner attribute is not permitted in this context
+#[cfg(FALSE)] fn e() { let _ = #[attr] ..#[attr] 0; }
+//~^ ERROR expected expression, found `..`
+#[cfg(FALSE)] fn e() { let _ = #[attr] ..; }
+//~^ ERROR expected expression, found `..`
+#[cfg(FALSE)] fn e() { let _ = #[attr] &#![attr] 0; }
+//~^ ERROR an inner attribute is not permitted in this context
+#[cfg(FALSE)] fn e() { let _ = #[attr] &mut #![attr] 0; }
+//~^ ERROR an inner attribute is not permitted in this context
+#[cfg(FALSE)] fn e() { let _ = #[attr] if 0 {}; }
+//~^ ERROR attributes are not yet allowed on `if` expressions
+#[cfg(FALSE)] fn e() { let _ = if 0 #[attr] {}; }
+//~^ ERROR expected `{`, found `#`
+#[cfg(FALSE)] fn e() { let _ = if 0 {#![attr]}; }
+//~^ ERROR an inner attribute is not permitted in this context
+#[cfg(FALSE)] fn e() { let _ = if 0 {} #[attr] else {}; }
+//~^ ERROR expected one of
+#[cfg(FALSE)] fn e() { let _ = if 0 {} else #[attr] {}; }
+//~^ ERROR expected `{`, found `#`
+#[cfg(FALSE)] fn e() { let _ = if 0 {} else {#![attr]}; }
+//~^ ERROR an inner attribute is not permitted in this context
+#[cfg(FALSE)] fn e() { let _ = if 0 {} else #[attr] if 0 {}; }
+//~^ ERROR attributes are not yet allowed on `if` expressions
+//~| ERROR expected `{`, found `#`
+#[cfg(FALSE)] fn e() { let _ = if 0 {} else if 0 #[attr] {}; }
+//~^ ERROR expected `{`, found `#`
+#[cfg(FALSE)] fn e() { let _ = if 0 {} else if 0 {#![attr]}; }
+//~^ ERROR an inner attribute is not permitted in this context
+#[cfg(FALSE)] fn e() { let _ = #[attr] if let _ = 0 {}; }
+//~^ ERROR attributes are not yet allowed on `if` expressions
+#[cfg(FALSE)] fn e() { let _ = if let _ = 0 #[attr] {}; }
+//~^ ERROR expected `{`, found `#`
+#[cfg(FALSE)] fn e() { let _ = if let _ = 0 {#![attr]}; }
+//~^ ERROR an inner attribute is not permitted in this context
+#[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} #[attr] else {}; }
+//~^ ERROR expected one of
+#[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} else #[attr] {}; }
+//~^ ERROR expected `{`, found `#`
+#[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} else {#![attr]}; }
+//~^ ERROR an inner attribute is not permitted in this context
+#[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} else #[attr] if let _ = 0 {}; }
+//~^ ERROR attributes are not yet allowed on `if` expressions
+//~| ERROR expected `{`, found `#`
+#[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} else if let _ = 0 #[attr] {}; }
+//~^ ERROR expected `{`, found `#`
+#[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} else if let _ = 0 {#![attr]}; }
+//~^ ERROR an inner attribute is not permitted in this context
+
+#[cfg(FALSE)] fn s() { #[attr] #![attr] let _ = 0; }
+//~^ ERROR an inner attribute is not permitted following an outer attribute
+#[cfg(FALSE)] fn s() { #[attr] #![attr] 0; }
+//~^ ERROR an inner attribute is not permitted following an outer attribute
+#[cfg(FALSE)] fn s() { #[attr] #![attr] foo!(); }
+//~^ ERROR an inner attribute is not permitted following an outer attribute
+#[cfg(FALSE)] fn s() { #[attr] #![attr] foo![]; }
+//~^ ERROR an inner attribute is not permitted following an outer attribute
+#[cfg(FALSE)] fn s() { #[attr] #![attr] foo!{}; }
+//~^ ERROR an inner attribute is not permitted following an outer attribute
+
+// FIXME: Allow attributes in pattern constexprs?
+// note: requires parens in patterns to allow disambiguation
+
+#[cfg(FALSE)] fn e() { match 0 { 0..=#[attr] 10 => () } }
+//~^ ERROR `X..=` range patterns are not supported
+//~| ERROR expected one of `=>`, `if`, or `|`, found `#`
+#[cfg(FALSE)] fn e() { match 0 { 0..=#[attr] -10 => () } }
+//~^ ERROR `X..=` range patterns are not supported
+//~| ERROR expected one of `=>`, `if`, or `|`, found `#`
+#[cfg(FALSE)] fn e() { match 0 { 0..=-#[attr] 10 => () } }
+//~^ ERROR unexpected token: `#`
+#[cfg(FALSE)] fn e() { match 0 { 0..=#[attr] FOO => () } }
+//~^ ERROR `X..=` range patterns are not supported
+//~| ERROR expected one of `=>`, `if`, or `|`, found `#`
+
+// make sure we don't catch this bug again...
+#[cfg(FALSE)] fn e() { { fn foo() { #[attr]; } } }
+//~^ ERROR expected statement after outer attribute
+#[cfg(FALSE)] fn e() { { fn foo() { #[attr] } } }