Rust: Add more jump-to-def test cases and refine logic

Author: hvitved

rust/ql/lib/codeql/rust/internal/Definitions.qll

@@ -179,26 +179,46 @@ private class MethodUse extends Use instanceof NameRef {
   override string getUseType() { result = "method" }
 }
 
+// We don't have entities for the operator symbols, so we approximate a location.
+// The location spans are chosen so that they align with rust-analyzer's jump-to-def
+// behavior in VS Code, which means using weird locations where the end column is
+// before the start column in the case of unary prefix operations.
+private predicate operatorHasLocationInfo(
+  Operation o, string filepath, int startline, int startcolumn, int endline, int endcolumn
+) {
+  o =
+    // `-x`; placing the cursor before `-` jumps to `neg`, placing it after jumps to `x`
+    any(PrefixExpr pe |
+      pe.getLocation().hasLocationInfo(filepath, startline, startcolumn, _, _) and
+      endline = startline and
+      endcolumn = startcolumn - 1
+    )
+  or
+  o =
+    // `x + y`: placing the cursor before or after `+` jumps to `add`
+    // `x+ y`: placing the cursor before `+` jumps to `x`, after `+` jumps to `add`
+    any(BinaryExpr be |
+      be.getLhs().getLocation().hasLocationInfo(filepath, _, _, startline, startcolumn - 2) and
+      be.getRhs().getLocation().hasLocationInfo(filepath, endline, endcolumn + 2, _, _) and
+      (
+        startline < endline
+        or
+        endcolumn = startcolumn
+      )
+    )
+}
+
 private class OperationUse extends Use instanceof Operation {
+  OperationUse() { operatorHasLocationInfo(this, _, _, _, _, _) }
+
   override Definition getDefinition() { result.asItemNode() = this.(Call).getStaticTarget() }
 
   override string getUseType() { result = "method" }
 
   override predicate hasLocationInfo(
     string filepath, int startline, int startcolumn, int endline, int endcolumn
   ) {
-    // We don't have entities for the operator symbols, so approximate a location
-    this =
-      any(PrefixExpr pe |
-        pe.getLocation().hasLocationInfo(filepath, startline, startcolumn, _, _) and
-        pe.getExpr().getLocation().hasLocationInfo(_, endline, endcolumn + 2, _, _)
-      )
-    or
-    this =
-      any(BinaryExpr be |
-        be.getLhs().getLocation().hasLocationInfo(filepath, _, _, startline, startcolumn - 2) and
-        be.getRhs().getLocation().hasLocationInfo(filepath, endline, endcolumn + 2, _, _)
-      )
+    operatorHasLocationInfo(this, filepath, startline, startcolumn, endline, endcolumn)
   }
 }
 
@@ -207,10 +227,13 @@ private class IndexExprUse extends Use instanceof IndexExpr {
 
   override string getUseType() { result = "method" }
 
+  // We don't have entities for the bracket symbols, so approximate a location
+  // The location spans are chosen so that they align with rust-analyzer's jump-to-def
+  // behavior in VS Code.
   override predicate hasLocationInfo(
     string filepath, int startline, int startcolumn, int endline, int endcolumn
   ) {
-    // We don't have entities for the brackets, so approximate a location
+    // `x[y]`: placing the cursor after `]` jumps to `index`
     super.getIndex().getLocation().hasLocationInfo(filepath, _, _, startline, startcolumn - 2) and
     this.getLocation().hasLocationInfo(_, _, _, endline, endcolumn)
   }

rust/ql/test/library-tests/definitions/Definitions.expected

@@ -73,5 +73,13 @@
 | main.rs:68:5:68:5 | S | main.rs:3:1:4:9 | struct S | path |
 | main.rs:68:7:68:7 | ... + ... | main.rs:19:5:21:5 | fn add | method |
 | main.rs:68:9:68:9 | S | main.rs:3:1:4:9 | struct S | path |
-| main.rs:69:5:69:5 | S | main.rs:3:1:4:9 | struct S | path |
-| main.rs:69:9:69:8 | S[0] | main.rs:27:5:29:5 | fn index | method |
+| main.rs:70:13:70:13 | S | main.rs:3:1:4:9 | struct S | path |
+| main.rs:70:15:70:15 | S | main.rs:3:1:4:9 | struct S | path |
+| main.rs:72:13:72:13 | S | main.rs:3:1:4:9 | struct S | path |
+| main.rs:72:15:73:4 | ... + ... | main.rs:19:5:21:5 | fn add | method |
+| main.rs:73:6:73:6 | S | main.rs:3:1:4:9 | struct S | path |
+| main.rs:75:13:75:13 | S | main.rs:3:1:4:9 | struct S | path |
+| main.rs:75:15:77:3 | ... + ... | main.rs:19:5:21:5 | fn add | method |
+| main.rs:77:5:77:5 | S | main.rs:3:1:4:9 | struct S | path |
+| main.rs:78:5:78:5 | S | main.rs:3:1:4:9 | struct S | path |
+| main.rs:78:9:78:8 | S[0] | main.rs:27:5:29:5 | fn index | method |

rust/ql/test/library-tests/definitions/main.rs

@@ -66,5 +66,14 @@ fn main() {
     M1::S2::<S>::new(S);
     -S;
     S + S;
+    #[rustfmt::skip]
+    let x = S+S;
+    #[rustfmt::skip]
+    let x = S
+    +S;
+    #[rustfmt::skip]
+    let x = S
+    +
+    S;
     S[0];
 }