Recover from named params while parse_path

xizheyin · xizheyin · commit c643bb2fb790 · 2025-05-06T16:52:07.000+08:00
Signed-off-by: xizheyin &lt;xizheyin@smail.nju.edu.cn&gt;
diff --git a/compiler/rustc_parse/messages.ftl b/compiler/rustc_parse/messages.ftl
@@ -702,6 +702,9 @@ parse_parenthesized_lifetime_suggestion = remove the parentheses
 parse_path_double_colon = path separator must be a double colon
     .suggestion = use a double colon instead
 
+parse_path_found_named_params = syntax does not allow named arguments
+    .suggestion = remove name of the param
+
 parse_pattern_method_param_without_body = patterns aren't allowed in methods without bodies
     .suggestion = give this argument a name or use an underscore to ignore it
 
diff --git a/compiler/rustc_parse/src/errors.rs b/compiler/rustc_parse/src/errors.rs
@@ -1591,6 +1591,14 @@ pub(crate) struct ExpectedFnPathFoundFnKeyword {
     pub fn_token_span: Span,
 }
 
+#[derive(Diagnostic)]
+#[diag(parse_path_found_named_params)]
+pub(crate) struct FnPathFoundNamedParams {
+    #[primary_span]
+    #[suggestion(applicability = "machine-applicable", code = "")]
+    pub named_param_span: Span,
+}
+
 #[derive(Diagnostic)]
 #[diag(parse_path_double_colon)]
 pub(crate) struct PathSingleColon {
diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs
@@ -2922,7 +2922,11 @@ impl<'a> Parser<'a> {
     /// Parses a single function parameter.
     ///
     /// - `self` is syntactically allowed when `first_param` holds.
-    fn parse_param_general(&mut self, req_name: ReqName, first_param: bool) -> PResult<'a, Param> {
+    pub(super) fn parse_param_general(
+        &mut self,
+        req_name: ReqName,
+        first_param: bool,
+    ) -> PResult<'a, Param> {
         let lo = self.token.span;
         let attrs = self.parse_outer_attributes()?;
         self.collect_tokens(None, attrs, ForceCollect::No, |this, attrs| {
@@ -3156,7 +3160,7 @@ impl<'a> Parser<'a> {
         Ok(Some(Param::from_self(AttrVec::default(), eself, eself_ident)))
     }
 
-    fn is_named_param(&self) -> bool {
+    pub(super) fn is_named_param(&self) -> bool {
         let offset = match &self.token.kind {
             token::OpenInvisible(origin) => match origin {
                 InvisibleOrigin::MetaVar(MetaVarKind::Pat(_)) => {
diff --git a/compiler/rustc_parse/src/parser/path.rs b/compiler/rustc_parse/src/parser/path.rs
@@ -15,7 +15,7 @@ use tracing::debug;
 
 use super::ty::{AllowPlus, RecoverQPath, RecoverReturnSign};
 use super::{Parser, Restrictions, TokenType};
-use crate::errors::{self, PathSingleColon, PathTripleColon};
+use crate::errors::{self, FnPathFoundNamedParams, PathSingleColon, PathTripleColon};
 use crate::exp;
 use crate::parser::{CommaRecoveryMode, RecoverColon, RecoverComma};
 
@@ -396,8 +396,21 @@ impl<'a> Parser<'a> {
                         snapshot = Some(self.create_snapshot_for_diagnostic());
                     }
 
-                    let (inputs, _) = match self.parse_paren_comma_seq(|p| p.parse_ty()) {
-                        Ok(output) => output,
+                    let dcx = self.dcx();
+                    let (inputs, _) = match self.parse_paren_comma_seq(|p| {
+                        if p.is_named_param() {
+                            let param = p.parse_param_general(|_| false, false);
+                            if let Ok(ref param) = param {
+                                dcx.emit_err(FnPathFoundNamedParams {
+                                    named_param_span: param.pat.span,
+                                });
+                            }
+                            param.map(|param| param.ty)
+                        } else {
+                            p.parse_ty()
+                        }
+                    }) {
+                        Ok((output, trailing)) => (output, trailing),
                         Err(mut error) if prev_token_before_parsing == token::PathSep => {
                             error.span_label(
                                 prev_token_before_parsing.span.to(token_before_parsing.span),
diff --git a/tests/ui/fn/fn-trait-use-named-params-issue-140169.rs b/tests/ui/fn/fn-trait-use-named-params-issue-140169.rs
@@ -1,6 +1,8 @@
 fn g(_: fn(a: u8)) {}
-fn x(_: impl Fn(u8, vvvv: u8)) {} //~ ERROR expected one of `!`, `(`, `)`, `+`, `,`, `::`, or `<`, found `:`
-fn y(_: impl Fn(aaaa: u8, u8)) {} //~ ERROR expected one of `!`, `(`, `)`, `+`, `,`, `::`, or `<`, found `:`
-fn z(_: impl Fn(aaaa: u8, vvvv: u8)) {} //~ ERROR expected one of `!`, `(`, `)`, `+`, `,`, `::`, or `<`, found `:`
+fn x(_: impl Fn(u8, vvvv: u8)) {} //~ ERROR syntax does not allow named arguments
+fn y(_: impl Fn(aaaa: u8, u8)) {} //~ ERROR syntax does not allow named arguments
+fn z(_: impl Fn(aaaa: u8, vvvv: u8)) {}
+//~^ ERROR syntax does not allow named arguments
+//~| ERROR syntax does not allow named arguments
 
 fn main(){}
diff --git a/tests/ui/fn/fn-trait-use-named-params-issue-140169.stderr b/tests/ui/fn/fn-trait-use-named-params-issue-140169.stderr
@@ -1,20 +1,26 @@
-error: expected one of `!`, `(`, `)`, `+`, `,`, `::`, or `<`, found `:`
-  --> $DIR/fn-trait-use-named-params-issue-140169.rs:2:25
+error: syntax does not allow named arguments
+  --> $DIR/fn-trait-use-named-params-issue-140169.rs:2:21
    |
 LL | fn x(_: impl Fn(u8, vvvv: u8)) {}
-   |                         ^ expected one of 7 possible tokens
+   |                     ^^^^ help: remove name of the param
 
-error: expected one of `!`, `(`, `)`, `+`, `,`, `::`, or `<`, found `:`
-  --> $DIR/fn-trait-use-named-params-issue-140169.rs:3:21
+error: syntax does not allow named arguments
+  --> $DIR/fn-trait-use-named-params-issue-140169.rs:3:17
    |
 LL | fn y(_: impl Fn(aaaa: u8, u8)) {}
-   |                     ^ expected one of 7 possible tokens
+   |                 ^^^^ help: remove name of the param
 
-error: expected one of `!`, `(`, `)`, `+`, `,`, `::`, or `<`, found `:`
-  --> $DIR/fn-trait-use-named-params-issue-140169.rs:4:21
+error: syntax does not allow named arguments
+  --> $DIR/fn-trait-use-named-params-issue-140169.rs:4:17
    |
 LL | fn z(_: impl Fn(aaaa: u8, vvvv: u8)) {}
-   |                     ^ expected one of 7 possible tokens
+   |                 ^^^^ help: remove name of the param
 
-error: aborting due to 3 previous errors
+error: syntax does not allow named arguments
+  --> $DIR/fn-trait-use-named-params-issue-140169.rs:4:27
+   |
+LL | fn z(_: impl Fn(aaaa: u8, vvvv: u8)) {}
+   |                           ^^^^ help: remove name of the param
+
+error: aborting due to 4 previous errors
 
diff --git a/tests/ui/parser/diagnostics-parenthesized-type-arguments-ice-issue-122345.rs b/tests/ui/parser/diagnostics-parenthesized-type-arguments-ice-issue-122345.rs
@@ -2,8 +2,10 @@
 
 fn main() {
     unsafe {
-        dealloc(ptr2, Layout::(x: !)(1, 1)); //~ ERROR: expected one of `!`, `(`, `)`, `+`, `,`, `::`, or `<`, found `:`
-        //~^ ERROR: expected one of `.`, `;`, `?`, `}`, or an operator, found `)`
-        //~| NOTE while parsing this parenthesized list of type arguments starting here
+        dealloc(ptr2, Layout::(x: !)(1, 1)); //~ ERROR syntax does not allow named arguments
+        //~^ ERROR cannot find function `dealloc` in this scope [E0425]
+        //~| ERROR cannot find value `ptr2` in this scope [E0425]
+        //~| ERROR the `!` type is experimental [E0658]
+        //~| ERROR cannot find function, tuple struct or tuple variant `Layout` in this scope [E0425]
     }
 }
diff --git a/tests/ui/parser/diagnostics-parenthesized-type-arguments-ice-issue-122345.stderr b/tests/ui/parser/diagnostics-parenthesized-type-arguments-ice-issue-122345.stderr
@@ -1,16 +1,43 @@
-error: expected one of `!`, `(`, `)`, `+`, `,`, `::`, or `<`, found `:`
-  --> $DIR/diagnostics-parenthesized-type-arguments-ice-issue-122345.rs:5:33
+error: syntax does not allow named arguments
+  --> $DIR/diagnostics-parenthesized-type-arguments-ice-issue-122345.rs:5:32
    |
 LL |         dealloc(ptr2, Layout::(x: !)(1, 1));
-   |                             --- ^ expected one of 7 possible tokens
-   |                             |
-   |                             while parsing this parenthesized list of type arguments starting here
+   |                                ^ help: remove name of the param
 
-error: expected one of `.`, `;`, `?`, `}`, or an operator, found `)`
-  --> $DIR/diagnostics-parenthesized-type-arguments-ice-issue-122345.rs:5:43
+error[E0425]: cannot find function `dealloc` in this scope
+  --> $DIR/diagnostics-parenthesized-type-arguments-ice-issue-122345.rs:5:9
    |
 LL |         dealloc(ptr2, Layout::(x: !)(1, 1));
-   |                                           ^ expected one of `.`, `;`, `?`, `}`, or an operator
+   |         ^^^^^^^ not found in this scope
+   |
+help: consider importing this function
+   |
+LL + use std::alloc::dealloc;
+   |
+
+error[E0425]: cannot find value `ptr2` in this scope
+  --> $DIR/diagnostics-parenthesized-type-arguments-ice-issue-122345.rs:5:17
+   |
+LL |         dealloc(ptr2, Layout::(x: !)(1, 1));
+   |                 ^^^^ not found in this scope
+
+error[E0658]: the `!` type is experimental
+  --> $DIR/diagnostics-parenthesized-type-arguments-ice-issue-122345.rs:5:35
+   |
+LL |         dealloc(ptr2, Layout::(x: !)(1, 1));
+   |                                   ^
+   |
+   = note: see issue #35121 <https://github.com/rust-lang/rust/issues/35121> for more information
+   = help: add `#![feature(never_type)]` 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[E0425]: cannot find function, tuple struct or tuple variant `Layout` in this scope
+  --> $DIR/diagnostics-parenthesized-type-arguments-ice-issue-122345.rs:5:23
+   |
+LL |         dealloc(ptr2, Layout::(x: !)(1, 1));
+   |                       ^^^^^^ not found in this scope
 
-error: aborting due to 2 previous errors
+error: aborting due to 5 previous errors
 
+Some errors have detailed explanations: E0425, E0658.
+For more information about an error, try `rustc --explain E0425`.

Original file line number	Diff line number	Diff line change
`@@ -2,8 +2,10 @@`
`2`	`2`
`3`	`3`	`fn main() {`
`4`	`4`	`unsafe {`
`5`		- dealloc(ptr2, Layout::(x: !)(1, 1)); //~ ERROR: expected one of `!`, `(`, `)`, `+`, `,`, `::`, or `<`, found `:`
`6`		- //~^ ERROR: expected one of `.`, `;`, `?`, `}`, or an operator, found `)`
`7`		`- //~\| NOTE while parsing this parenthesized list of type arguments starting here`
	`5`	`+ dealloc(ptr2, Layout::(x: !)(1, 1)); //~ ERROR syntax does not allow named arguments`
	`6`	+ //~^ ERROR cannot find function `dealloc` in this scope [E0425]
	`7`	+ //~\| ERROR cannot find value `ptr2` in this scope [E0425]
	`8`	+ //~\| ERROR the `!` type is experimental [E0658]
	`9`	+ //~\| ERROR cannot find function, tuple struct or tuple variant `Layout` in this scope [E0425]
`8`	`10`	`}`
`9`	`11`	`}`