sqf: optimize _this call (#802)

libs/sqf/src/analyze/lints/s22_this_call.rs

@@ -0,0 +1,144 @@
+use std::{ops::Range, sync::Arc};
+
+use hemtt_common::config::LintConfig;
+use hemtt_workspace::{
+    lint::{AnyLintRunner, Lint, LintRunner},
+    reporting::{Code, Codes, Diagnostic, Processed, Severity},
+};
+
+use crate::{analyze::SqfLintData, BinaryCommand, Expression};
+
+crate::lint!(LintS22InVehicleCheck);
+
+impl Lint<SqfLintData> for LintS22InVehicleCheck {
+    fn ident(&self) -> &str {
+        "this_call"
+    }
+
+    fn sort(&self) -> u32 {
+        220
+    }
+
+    fn description(&self) -> &str {
+        "Checks for usage of `_this call`, where `_this` is not necessary"
+    }
+
+    fn documentation(&self) -> &str {
+        r"### Example
+
+**Incorrect**
+```sqf
+_this call _my_function;
+```
+**Correct**
+```sqf
+call _my_function;
+```
+
+### Explanation
+
+When using `call`, the called code will inherit `_this` from the calling scope. This means that `_this` is not necessary in the call, and can be omitted for better performance.
+"
+    }
+
+    fn default_config(&self) -> LintConfig {
+        LintConfig::help().with_enabled(false)
+    }
+
+    fn runners(&self) -> Vec<Box<dyn AnyLintRunner<SqfLintData>>> {
+        vec![Box::new(Runner)]
+    }
+}
+
+struct Runner;
+impl LintRunner<SqfLintData> for Runner {
+    type Target = crate::Expression;
+
+    fn run(
+        &self,
+        _project: Option<&hemtt_common::config::ProjectConfig>,
+        config: &LintConfig,
+        processed: Option<&hemtt_workspace::reporting::Processed>,
+        target: &Self::Target,
+        _data: &SqfLintData,
+    ) -> Codes {
+        let Some(processed) = processed else {
+            return Vec::new();
+        };
+        let Expression::BinaryCommand(BinaryCommand::Named(cmd), lhs, _, _) = target else {
+            return Vec::new();
+        };
+
+        if cmd.to_lowercase() != "call" {
+            return Vec::new();
+        }
+
+        if matches!(&**lhs, Expression::Variable(name, _) if name == "_this") {
+            return vec![Arc::new(CodeS22ThisCall::new(
+                lhs.span(),
+                processed,
+                config.severity(),
+            ))];
+        }
+
+        Vec::new()
+    }
+}
+
+#[allow(clippy::module_name_repetitions)]
+pub struct CodeS22ThisCall {
+    span: Range<usize>,
+    severity: Severity,
+    diagnostic: Option<Diagnostic>,
+}
+
+impl Code for CodeS22ThisCall {
+    fn ident(&self) -> &'static str {
+        "L-S22"
+    }
+
+    fn link(&self) -> Option<&str> {
+        Some("/analysis/sqf.html#this_call")
+    }
+
+    fn severity(&self) -> Severity {
+        self.severity
+    }
+
+    fn message(&self) -> String {
+        "Unnecessary `_this` in `call`".to_string()
+    }
+
+    fn label_message(&self) -> String {
+        String::new()
+    }
+
+    fn note(&self) -> Option<String> {
+        Some("`call` inherits `_this` from the calling scope".to_string())
+    }
+
+    fn help(&self) -> Option<String> {
+        Some("Remove `_this` from the call".to_string())
+    }
+
+    fn diagnostic(&self) -> Option<Diagnostic> {
+        self.diagnostic.clone()
+    }
+}
+
+impl CodeS22ThisCall {
+    #[must_use]
+    pub fn new(span: Range<usize>, processed: &Processed, severity: Severity) -> Self {
+        Self {
+            span,
+            severity,
+            diagnostic: None,
+        }
+        .generate_processed(processed)
+    }
+
+    fn generate_processed(mut self, processed: &Processed) -> Self {
+        self.diagnostic = Diagnostic::new_for_processed(&self, self.span.clone(), processed);
+        self
+    }
+}

libs/sqf/src/compiler/optimizer/mod.rs

@@ -144,6 +144,15 @@ impl Expression {
                                 left_o = consumable;
                             }
                         }
+                        "call" => {
+                            if matches!(&left_o, Self::Variable(name, _) if name == "_this") {
+                                return Self::UnaryCommand(
+                                    UnaryCommand::Named("call".into()),
+                                    Box::new(right_o),
+                                    range.clone(),
+                                );
+                            }
+                        }
                         _ => {}
                     },
                     BinaryCommand::Add => {

libs/sqf/tests/lints.rs

@@ -86,3 +86,4 @@ analyze!(s17_var_all_caps);
 analyze!(s18_in_vehicle_check);
 analyze!(s20_bool_static_comparison);
 analyze!(s21_invalid_comparisons);
+analyze!(s22_this_call);

libs/sqf/tests/lints/project_tests.toml

@@ -14,3 +14,6 @@ enabled = true
 options.ignore = [
     "AM_IGNORED",
 ]
+
+[lints.sqf.this_call]
+enabled = true

libs/sqf/tests/lints/s22_this_call/source.sqf

@@ -0,0 +1,7 @@
+private _my_fnc = {
+    systemChat _this;
+};
+
+_this call _my_fnc;
+
+123 call _my_fnc;

libs/sqf/tests/lints/s22_this_call/stdout.ansi

@@ -0,0 +1,9 @@
+help[L-S22]: Unnecessary `_this` in `call`
+  ┌─ source.sqf:5:1
+  │
+5 │ _this call _my_fnc;
+  │ ^^^^^
+  │
+  = note: `call` inherits `_this` from the calling scope
+  = help: Remove `_this` from the call
+