feat(tvix): Add a pos field to more expr classes r/1906

To aid in both debugging and (eventually) printing stacktraces, add a
Pos member to a few more Expr variants.

Change-Id: Ic1d2a056fc7e6c07bc3e79fa38845cb4a5da5ca5
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2133
Tested-by: BuildkiteCI
Reviewed-by: tazjin <mail@tazj.in>

2 files changed, 14 insertions, 6 deletions

diff --git a/third_party/nix/src/libexpr/nixexpr.hh b/third_party/nix/src/libexpr/nixexpr.hh
index 22b5f871f0..16b58dec2e 100644
--- a/third_party/nix/src/libexpr/nixexpr.hh
+++ b/third_party/nix/src/libexpr/nixexpr.hh
@@ -179,9 +179,12 @@ struct ExprSelect : Expr {
 };
 
 struct ExprOpHasAttr : Expr {
+  Pos pos;
   Expr* e;
   AttrPath attrPath;
   ExprOpHasAttr(Expr* e, const AttrPath& attrPath) : e(e), attrPath(attrPath){};
+  ExprOpHasAttr(const Pos& pos, Expr* e, const AttrPath& attrPath)
+      : pos(pos), e(e), attrPath(attrPath){};
   COMMON_METHODS
 };
 
@@ -279,9 +282,12 @@ struct ExprWith : Expr {
 };
 
 struct ExprIf : Expr {
+  Pos pos;
   Expr *cond, *then, *else_;
   ExprIf(Expr* cond, Expr* then, Expr* else_)
       : cond(cond), then(then), else_(else_){};
+  ExprIf(const Pos& pos, Expr* cond, Expr* then, Expr* else_)
+      : pos(pos), cond(cond), then(then), else_(else_){};
   COMMON_METHODS
 };
 
@@ -294,8 +300,10 @@ struct ExprAssert : Expr {
 };
 
 struct ExprOpNot : Expr {
+  Pos pos;
   Expr* e;
-  ExprOpNot(Expr* e) : e(e){};
+  explicit ExprOpNot(Expr* e) : e(e){};
+  ExprOpNot(const Pos& pos, Expr* e) : pos(pos), e(e){};
   COMMON_METHODS
 };
 
diff --git a/third_party/nix/src/libexpr/parser.y b/third_party/nix/src/libexpr/parser.y
index ba6490e60a..a8af06802f 100644
--- a/third_party/nix/src/libexpr/parser.y
+++ b/third_party/nix/src/libexpr/parser.y
@@ -121,15 +121,15 @@ expr_function
   ;
 
 expr_if
-  : IF expr THEN expr ELSE expr { $$ = new ExprIf($2, $4, $6); }
+  : IF expr THEN expr ELSE expr { $$ = new ExprIf(CUR_POS, $2, $4, $6); }
   | expr_op
   ;
 
 expr_op
-  : '!' expr_op %prec NOT { $$ = new ExprOpNot($2); }
+  : '!' expr_op %prec NOT { $$ = new ExprOpNot(CUR_POS, $2); }
   | '-' expr_op %prec NEGATE { $$ = new ExprApp(CUR_POS, new ExprApp(new ExprVar(data->symbols.Create("__sub")), new ExprInt(0)), $2); }
-  | expr_op EQ expr_op { $$ = new ExprOpEq($1, $3); }
-  | expr_op NEQ expr_op { $$ = new ExprOpNEq($1, $3); }
+  | expr_op EQ expr_op { $$ = new ExprOpEq(CUR_POS, $1, $3); }
+  | expr_op NEQ expr_op { $$ = new ExprOpNEq(CUR_POS, $1, $3); }
   | expr_op '<' expr_op { $$ = new ExprApp(CUR_POS, new ExprApp(new ExprVar(data->symbols.Create("__lessThan")), $1), $3); }
   | expr_op LEQ expr_op { $$ = new ExprOpNot(new ExprApp(CUR_POS, new ExprApp(new ExprVar(data->symbols.Create("__lessThan")), $3), $1)); }
   | expr_op '>' expr_op { $$ = new ExprApp(CUR_POS, new ExprApp(new ExprVar(data->symbols.Create("__lessThan")), $3), $1); }
@@ -138,7 +138,7 @@ expr_op
   | expr_op OR expr_op { $$ = new ExprOpOr(CUR_POS, $1, $3); }
   | expr_op IMPL expr_op { $$ = new ExprOpImpl(CUR_POS, $1, $3); }
   | expr_op UPDATE expr_op { $$ = new ExprOpUpdate(CUR_POS, $1, $3); }
-  | expr_op '?' attrpath { $$ = new ExprOpHasAttr($1, *$3); }
+  | expr_op '?' attrpath { $$ = new ExprOpHasAttr(CUR_POS, $1, *$3); }
   | expr_op '+' expr_op
     { $$ = new ExprConcatStrings(CUR_POS, false, new nix::VectorExprs({$1, $3})); }
   | expr_op '-' expr_op { $$ = new ExprApp(CUR_POS, new ExprApp(new ExprVar(data->symbols.Create("__sub")), $1), $3); }