Make internal errors in incremental compilation into actual errors

Previously they were warnings, which means we could miss them in the CI.

Author: smarter

compiler/src/dotty/tools/dotc/sbt/ExtractAPI.scala

@@ -1,6 +1,7 @@
 package dotty.tools.dotc
 package sbt
 
+import ExtractDependencies.internalError
 import ast.{Positioned, Trees, tpd, untpd}
 import core._
 import core.Decorators._
@@ -30,7 +31,7 @@ import scala.collection.mutable
  *
  *  See the documentation of `ExtractAPICollector`, `ExtractDependencies`,
  *  `ExtractDependenciesCollector` and
- *  http://www.scala-sbt.org/0.13/docs/Understanding-Recompilation.html for more
+ *  http://www.scala-sbt.org/1.x/docs/Understanding-Recompilation.html for more
  *  information on incremental recompilation.
  *
  *  The following flags affect this phase:
@@ -515,7 +516,7 @@ private class ExtractAPICollector(using Context) extends ThunkHolder {
       case tp: TypeVar =>
         apiType(tp.underlying)
       case _ => {
-        report.warning(i"sbt-api: Unhandled type ${tp.getClass} : $tp")
+        internalError(i"Unhandled type $tp of class ${tp.getClass}")
         Constants.emptyType
       }
     }
@@ -660,9 +661,10 @@ private class ExtractAPICollector(using Context) extends ThunkHolder {
             // The hashCode of the name itself is not stable across compiler instances
             h = MurmurHash3.mix(h, n.toString.hashCode)
           case elem =>
-            report.warning(
-              i"""Internal error: Don't know how to produce a stable hash for `$elem` of unknown class ${elem.getClass}
-                 |Incremental compilation might not work correctly.""", tree.sourcePos)
+            internalError(
+              i"Don't know how to produce a stable hash for `$elem` of unknown class ${elem.getClass}",
+              tree.sourcePos)
+
             h = MurmurHash3.mix(h, elem.toString.hashCode)
       h
     end iteratorHash

compiler/src/dotty/tools/dotc/sbt/ExtractDependencies.scala

@@ -16,6 +16,7 @@ import dotty.tools.dotc.core.StdNames._
 import dotty.tools.dotc.core.Symbols._
 import dotty.tools.dotc.core.Types._
 import dotty.tools.dotc.transform.SymUtils._
+import dotty.tools.dotc.util.{SrcPos, NoSourcePosition}
 import dotty.tools.io
 import dotty.tools.io.{AbstractFile, PlainFile, ZipArchive}
 import xsbti.UseScope
@@ -139,7 +140,7 @@ class ExtractDependencies extends Phase {
             binaryDependency(pf.file, binaryClassName(classSegments))
 
         case _ =>
-          report.warning(s"sbt-deps: Ignoring dependency $depFile of class ${depFile.getClass}}")
+          internalError(s"Ignoring dependency $depFile of unknown class ${depFile.getClass}}", dep.from.srcPos)
       }
     }
 
@@ -163,6 +164,10 @@ class ExtractDependencies extends Phase {
 object ExtractDependencies {
   def classNameAsString(sym: Symbol)(using Context): String =
     sym.fullName.stripModuleClassSuffix.toString
+
+  /** Report an internal error in incremental compilation. */
+  def internalError(msg: => String, pos: SrcPos = NoSourcePosition)(using Context): Unit =
+    report.error(s"Internal error in the incremental compiler while compiling ${ctx.compilationUnit.source}: $msg", pos)
 }
 
 private case class ClassDependency(from: Symbol, to: Symbol, context: DependencyContext)