Count each statement once in coverage however often it lowers (#1366)

packages/compiler/src/frontend/lowering/lower-classes.ts

@@ -4598,8 +4598,7 @@ function lowerStaticFieldInitsInner(lowerer: Lowerer, info: ClassInfo): IrStmt[]
       continue;
     }
     const f = item.f;
-    lowerer.stats.statementsTotal++;
-    lowerer.bumpFileStat(locOf(f.initializer).file, "total");
+    lowerer.countStatement(f.initializer, locOf(f.initializer).file);
     const diagsBefore = lowerer.diags.length;
     const sinkMark = lowerer.diagSinkMark();
     try {
@@ -4635,8 +4634,7 @@ function lowerStaticFieldInitsInner(lowerer: Lowerer, info: ClassInfo): IrStmt[]
       out.push({ kind: "assign", localId: f.globalId, value, loc: locOf(f.initializer) });
     } catch (e) {
       if (!(e instanceof PoisonError)) throw e;
-      lowerer.stats.statementsFailed++;
-      lowerer.bumpFileStat(locOf(f.initializer).file, "failed");
+      lowerer.countStatementFailed(f.initializer, locOf(f.initializer).file);
       if (isJsSourceFile(f.initializer.getSourceFile())) {
         const fence =
           lowerer.diagSink === null
@@ -7764,8 +7762,7 @@ export function fieldInitStmts(lowerer: Lowerer, info: ClassInfo, thisLocal: IrL
       });
     }
     if (!f.initializer) continue;
-    lowerer.stats.statementsTotal++;
-    lowerer.bumpFileStat(locOf(f.initializer).file, "total");
+    lowerer.countStatement(f.initializer, locOf(f.initializer).file);
     const diagsBefore = lowerer.diags.length;
     const sinkMark = lowerer.diagSinkMark();
     try {
@@ -7780,8 +7777,7 @@ export function fieldInitStmts(lowerer: Lowerer, info: ClassInfo, thisLocal: IrL
       });
     } catch (e) {
       if (!(e instanceof PoisonError)) throw e;
-      lowerer.stats.statementsFailed++;
-      lowerer.bumpFileStat(locOf(f.initializer).file, "failed");
+      lowerer.countStatementFailed(f.initializer, locOf(f.initializer).file);
       if (isJsSourceFile(f.initializer.getSourceFile())) {
         const fence =
           lowerer.diagSink === null

packages/compiler/src/frontend/lowering/lower-stmts.ts

@@ -689,10 +689,7 @@ export function lowerStmts(lowerer: Lowerer, stmts: readonly ts.Statement[]): Ir
       entry.index = i;
       if (unreachable && skipsWhenUnreachable(stmt)) continue;
       if (inFunction && isAbruptStatement(stmt)) unreachable = true;
-      if (!lowerer.suppressStats) {
-        lowerer.stats.statementsTotal++;
-        if (sf !== undefined) lowerer.bumpFileStat(sf.fileName, "total");
-      }
+      if (!lowerer.suppressStats) lowerer.countStatement(stmt, sf?.fileName);
       const diagsBefore = lowerer.diags.length;
       const sinkMark = lowerer.diagSinkMark();
       try {
@@ -757,10 +754,7 @@ export function lowerStmts(lowerer: Lowerer, stmts: readonly ts.Statement[]): Ir
         } else if (!(e instanceof PoisonError)) {
           throw e;
         }
-        if (!lowerer.suppressStats) {
-          lowerer.stats.statementsFailed++;
-          if (sf !== undefined) lowerer.bumpFileStat(sf.fileName, "failed");
-        }
+        if (!lowerer.suppressStats) lowerer.countStatementFailed(stmt, sf?.fileName);
         lowerer.noteBlockedBindings(stmt);
         // The runtime-fence conversion (JS sources, direct diagnostics
         // only — a capture wrapper in force means collection owns the

packages/compiler/src/frontend/lowering/lowerer.ts

@@ -2925,6 +2925,32 @@ export class Lowerer {
    * pass skips it (attribution describes the build). */
   readonly statsByFile = new Map<string, { total: number; failed: number }>();
 
+  /** Statements and field initializers already in the coverage totals, and
+   * those already counted as failed. Speculative lowering can lower one
+   * function body several times: each receiver probe of
+   * `(function () { ... }).call(this)` lowers it. A source statement counts
+   * once however many times it lowers. */
+  private readonly countedStatements = new Set<ts.Node>();
+  private readonly failedStatements = new Set<ts.Node>();
+
+  /** Adds `node` to the coverage totals unless it is already counted (the
+   * caller checks suppressStats). */
+  countStatement(node: ts.Node, file: string | undefined): void {
+    if (this.countedStatements.has(node)) return;
+    this.countedStatements.add(node);
+    this.stats.statementsTotal++;
+    if (file !== undefined) this.bumpFileStat(file, "total");
+  }
+
+  /** Counts `node` as failed unless it already is (the caller checks
+   * suppressStats). */
+  countStatementFailed(node: ts.Node, file: string | undefined): void {
+    if (this.failedStatements.has(node)) return;
+    this.failedStatements.add(node);
+    this.stats.statementsFailed++;
+    if (file !== undefined) this.bumpFileStat(file, "failed");
+  }
+
   /** Bumps the per-file attribution counter (no-op unless provenance is
    * active and this is the emit/discovery lane — mirror the CALLER's
    * suppressStats guard, this method only gates remainder). */

tests/corpus/6110-cjs-speculative-wrapper-fences.cjs

@@ -5,8 +5,7 @@
 // and `typeof module.exports` compile; a statement with no static lowering
 // (here `module.exports` passed as a value in the class base) compiles to
 // its runtime fence instead of vanishing. It never runs, so the binary
-// matches Node. Coverage counts that one fenced statement once: the class
-// base's body is lowered once.
+// matches Node.
 const verbose = process.argv.length > 99;
 (function () {
   var root = this;