Make OperationContext not hold a Parser via Rc

Exploit Rust's lifetimes. This will lead to simplifications.

src/builtins/commandline.rs

@@ -143,7 +143,7 @@ fn write_part(
                     &mut args,
                     ExpandFlags::SKIP_CMDSUBST,
                     &OperationContext::foreground(
-                        parser.shared(),
+                        parser,
                         Box::new(no_cancel),
                         COMMANDLINE_TOKENS_MAX_EXPANSION,
                     ),

src/operation_context.rs

@@ -1,7 +1,7 @@
 use crate::common::CancelChecker;
 use crate::env::EnvDyn;
 use crate::env::{EnvStack, Environment};
-use crate::parser::{Parser, ParserRef};
+use crate::parser::Parser;
 use crate::proc::JobGroupRef;
 
 use crate::reader::read_generation_count;
@@ -21,11 +21,11 @@ pub const EXPANSION_LIMIT_BACKGROUND: usize = 512;
 enum Vars<'a> {
     // The parser, if this is a foreground operation. If this is a background operation, this may be
     // nullptr.
-    Parser(ParserRef),
+    Parser(&'a Parser),
     // A set of variables.
     Vars(&'a dyn Environment),
 
-    TestOnly(ParserRef, &'a dyn Environment),
+    TestOnly(&'a Parser, &'a dyn Environment),
 }
 
 /// A operation_context_t is a simple property bag which wraps up data needed for highlighting,
@@ -70,7 +70,7 @@ impl<'a> OperationContext<'a> {
 
     /// Construct from a full set of properties.
     pub fn foreground(
-        parser: ParserRef,
+        parser: &'a Parser,
         cancel_checker: CancelChecker,
         expansion_limit: usize,
     ) -> OperationContext<'a> {
@@ -83,7 +83,7 @@ impl<'a> OperationContext<'a> {
     }
 
     pub fn test_only_foreground(
-        parser: ParserRef,
+        parser: &'a Parser,
         vars: &'a dyn Environment,
         cancel_checker: CancelChecker,
     ) -> OperationContext<'a> {

src/parser.rs

@@ -1134,9 +1134,9 @@ impl Parser {
     }
 
     /// Return the operation context for this parser.
-    pub fn context(&self) -> OperationContext<'static> {
+    pub fn context(&self) -> OperationContext<'_> {
         OperationContext::foreground(
-            self.shared(),
+            self,
             Box::new(|| signal_check_cancel() != 0),
             EXPANSION_LIMIT_DEFAULT,
         )

src/tests/complete.rs

@@ -43,8 +43,8 @@ fn test_complete() {
         },
     };
 
-    let parser = Parser::principal_parser().shared();
-    let ctx = OperationContext::test_only_foreground(parser.clone(), &vars, Box::new(no_cancel));
+    let parser = Parser::principal_parser();
+    let ctx = OperationContext::test_only_foreground(parser, &vars, Box::new(no_cancel));
 
     let do_complete = |cmd: &wstr, flags: CompletionRequestOptions| complete(cmd, flags, &ctx).0;
 
@@ -489,7 +489,7 @@ fn test_autosuggest_suggest_special() {
                 L!($command),
                 CompletionRequestOptions::default(),
                 &OperationContext::foreground(
-                    Parser::principal_parser().shared(),
+                    Parser::principal_parser(),
                     Box::new(no_cancel),
                     EXPANSION_LIMIT_DEFAULT,
                 ),

src/tests/expand.rs

@@ -27,7 +27,7 @@ fn expand_test_impl(
     let mut errors = ParseErrorList::new();
     let pwd = PwdEnvironment::default();
     let ctx = OperationContext::test_only_foreground(
-        Parser::principal_parser().shared(),
+        Parser::principal_parser(),
         &pwd,
         Box::new(no_cancel),
     );
@@ -358,14 +358,13 @@ fn test_expand_overflow() {
     let vals: Vec<WString> = (1..=64).map(|i| i.to_wstring()).collect();
     let expansion = WString::from_str(&str::repeat("$bigvar", 64));
 
-    let parser = Parser::principal_parser().shared();
+    let parser = Parser::principal_parser();
     parser.vars().push(true);
     let set = parser.vars().set(L!("bigvar"), EnvMode::LOCAL, vals);
     assert_eq!(set, EnvStackSetResult::Ok);
 
     let mut errors = ParseErrorList::new();
-    let ctx =
-        OperationContext::foreground(parser.clone(), Box::new(no_cancel), EXPANSION_LIMIT_DEFAULT);
+    let ctx = OperationContext::foreground(parser, Box::new(no_cancel), EXPANSION_LIMIT_DEFAULT);
 
     // We accept only 1024 completions.
     let mut output = CompletionReceiver::new(1024);

src/tests/parser.rs

@@ -614,7 +614,7 @@ fn test_eval_recursion_detection() {
     let _cleanup = test_init();
     // Ensure that we don't crash on infinite self recursion and mutual recursion. These must use
     // the principal parser because we cannot yet execute jobs on other parsers.
-    let parser = Parser::principal_parser().shared();
+    let parser = Parser::principal_parser();
     parser.eval(
         L!("function recursive ; recursive ; end ; recursive; "),
         &IoChain::new(),
@@ -665,7 +665,7 @@ fn test_eval_illegal_exit_code() {
 #[serial]
 fn test_eval_empty_function_name() {
     let _cleanup = test_init();
-    let parser = Parser::principal_parser().shared();
+    let parser = Parser::principal_parser();
     parser.eval(
         L!("function '' ; echo fail; exit 42 ; end ; ''"),
         &IoChain::new(),
@@ -676,7 +676,7 @@ fn test_eval_empty_function_name() {
 #[serial]
 fn test_expand_argument_list() {
     let _cleanup = test_init();
-    let parser = Parser::principal_parser().shared();
+    let parser = Parser::principal_parser();
     let comps: Vec<WString> = Parser::expand_argument_list(
         L!("alpha 'beta gamma' delta"),
         ExpandFlags::default(),