analyze: mir_op: comment explaining SubLoc to WhichPlace conversion

spernsteiner · spernsteiner · commit ba951826cb22 · 2024-12-09T09:54:20.000-08:00
diff --git a/c2rust-analyze/src/rewrite/expr/mir_op.rs b/c2rust-analyze/src/rewrite/expr/mir_op.rs
@@ -417,6 +417,9 @@ impl<'a, 'tcx> ExprRewriteVisitor<'a, 'tcx> {
                 }
                 SubLoc::Rvalue => {
                     which = Some(last_use::WhichPlace::Operand(0));
+                    // Note there may be more entries in `self.sub_loc` giving a more precise
+                    // position, as in `[SubLoc::Rvalue, SubLoc::CallArg(0)]`.  We keep looping
+                    // over `self.sub_loc` and take the last (most precise) entry.
                 }
                 SubLoc::CallArg(i) => {
                     // In a call, `WhichPlace::Operand(0)` refers to the callee function.

Original file line number	Diff line number	Diff line change
`@@ -417,6 +417,9 @@ impl<'a, 'tcx> ExprRewriteVisitor<'a, 'tcx> {`
`417`	`417`	`}`
`418`	`418`	`SubLoc::Rvalue => {`
`419`	`419`	`which = Some(last_use::WhichPlace::Operand(0));`
	`420`	+ // Note there may be more entries in `self.sub_loc` giving a more precise
	`421`	+ // position, as in `[SubLoc::Rvalue, SubLoc::CallArg(0)]`. We keep looping
	`422`	+ // over `self.sub_loc` and take the last (most precise) entry.
`420`	`423`	`}`
`421`	`424`	`SubLoc::CallArg(i) => {`
`422`	`425`	// In a call, `WhichPlace::Operand(0)` refers to the callee function.