Merge pull request #12061 from dotty-staging/fix-#10970

Disallow `@tailrec inline`

Author: nicolasstucki

compiler/src/dotty/tools/dotc/typer/Checking.scala

@@ -467,8 +467,11 @@ object Checking {
     if (sym.is(Trait) && sym.is(Final))
       fail(TraitsMayNotBeFinal(sym))
     // Skip ModuleVal since the annotation will also be on the ModuleClass
-    if (sym.hasAnnotation(defn.TailrecAnnot) && !sym.isOneOf(Method | ModuleVal))
-      fail(TailrecNotApplicable(sym))
+    if sym.hasAnnotation(defn.TailrecAnnot) then
+      if !sym.isOneOf(Method | ModuleVal) then
+        fail(TailrecNotApplicable(sym))
+      else if sym.is(Inline) then
+        fail("Inline methods cannot be @tailrec")
     if (sym.hasAnnotation(defn.NativeAnnot)) {
       if (!sym.is(Deferred))
         fail(NativeMembersMayNotHaveImplementation(sym))

tests/neg/i10970.scala

@@ -0,0 +1,3 @@
+import scala.annotation.tailrec
+
+@tailrec inline def foo() = ??? // error