Macro expansion errors are now wrapped

basis/stack-checker/errors/errors.factor

@@ -82,3 +82,8 @@ TUPLE: unknown-primitive-error ;
 
 : unknown-primitive-error ( -- * )
     \ unknown-primitive-error inference-warning ;
+
+TUPLE: transform-expansion-error word error ;
+
+: transform-expansion-error ( word error -- * )
+    \ transform-expansion-error inference-error ;

basis/stack-checker/errors/prettyprint/prettyprint.factor

@@ -79,3 +79,12 @@ M: inconsistent-recursive-call-error summary
 M: unknown-primitive-error summary
     drop
     "Cannot determine stack effect statically" ;
+
+M: transform-expansion-error summary
+    drop
+    "Compiler transform threw an error" ;
+
+M: transform-expansion-error error.
+    [ summary print ]
+    [ "Word: " write word>> . nl ]
+    [ error>> error. ] tri ;

basis/stack-checker/transforms/transforms-tests.factor

@@ -1,6 +1,6 @@
 IN: stack-checker.transforms.tests
 USING: sequences stack-checker.transforms tools.test math kernel
-quotations stack-checker accessors combinators words arrays
+quotations stack-checker stack-checker.errors accessors combinators words arrays
 classes classes.tuple ;
 
 : compose-n-quot ( word n -- quot' ) <repetition> >quotation ;
@@ -71,3 +71,10 @@ DEFER: curry-folding-test ( quot -- )
 
 [ f ] [ 1.0 member?-test ] unit-test
 [ t ] [ \ member?-test def>> first [ member?-test ] all? ] unit-test
+
+! Macro expansion should throw its own type of error
+: bad-macro ( -- ) ;
+
+\ bad-macro [ "OOPS" throw ] 0 define-transform
+
+[ [ bad-macro ] infer ] [ inference-error? ] must-fail-with

basis/stack-checker/transforms/transforms.factor

@@ -17,9 +17,14 @@ IN: stack-checker.transforms
         [ dup infer-word apply-word/effect ]
     } cond ;
 
+: call-transformer ( word stack quot -- newquot )
+    '[ _ _ with-datastack [ length 1 assert= ] [ first ] bi nip ]
+    [ transform-expansion-error ]
+    recover ;
+
 :: ((apply-transform)) ( word quot values stack rstate -- )
     rstate recursive-state
-    [ stack quot with-datastack first ] with-variable
+    [ word stack quot call-transformer ] with-variable
     [
         word inlined-dependency depends-on
         values [ length meta-d shorten-by ] [ #drop, ] bi