fix: improve trace remapping

Author: DylanPiercey

.changeset/smooth-olives-drum.md

@@ -0,0 +1,6 @@
+---
+"@marko/language-tools": patch
+"@marko/type-check": patch
+---
+
+Expose source/generated range helpers and use that when remapping generated traces in mtc.

packages/language-tools/src/util/extractor.ts

@@ -102,14 +102,15 @@ export class Extracted {
     if (sourceOffset !== undefined) return this.parsed.positionAt(sourceOffset);
   }
 
+  sourceRangeAt(generatedStart: number, generatedEnd: number) {
+    return this.#generatedToSource.rangeAt(generatedStart, generatedEnd);
+  }
+
   sourceLocationAt(
     generatedStart: number,
     generatedEnd: number,
   ): Location | undefined {
-    const sourceRange = this.#generatedToSource.rangeAt(
-      generatedStart,
-      generatedEnd,
-    );
+    const sourceRange = this.sourceRangeAt(generatedStart, generatedEnd);
     if (sourceRange) {
       return this.parsed.locationAt(sourceRange);
     }
@@ -126,14 +127,15 @@ export class Extracted {
     }
   }
 
+  generatedRangeAt(sourceStart: number, sourceEnd: number) {
+    return this.#sourceToGenerated.rangeAt(sourceStart, sourceEnd);
+  }
+
   generatedLocationAt(
     sourceStart: number,
     sourceEnd: number,
   ): Location | undefined {
-    const generatedRange = this.#sourceToGenerated.rangeAt(
-      sourceStart,
-      sourceEnd,
-    );
+    const generatedRange = this.generatedRangeAt(sourceStart, sourceEnd);
     if (generatedRange) {
       return getLocation(
         this.#generatedLines,

packages/type-check/src/run.ts

@@ -106,10 +106,16 @@ export default function run(opts: Options) {
         if (typeof fileName === "string") {
           const extracted = extractCache.get(getCanonicalFileName(fileName));
           if (extracted) {
+            const sourceRange = extracted.sourceRangeAt(args.pos, args.end);
+            if (sourceRange) {
+              args.pos = sourceRange.start;
+              args.end = sourceRange.end;
+            } else {
+              args.pos = args.end = undefined;
+            }
+
             (args as any).generatedPos = args.pos;
             (args as any).generatedEnd = args.end;
-            args.pos = extracted.sourceOffsetAt(args.pos);
-            args.end = extracted.sourceOffsetAt(args.end);
           }
         }
       }