use isProv only for caching

Author: smarter

Diff for: compiler/src/dotty/tools/dotc/core/TypeErasure.scala

@@ -96,11 +96,11 @@ object TypeErasure {
       val arity2 = tupleArity(tp.tp2)
       if arity1 == arity2 then arity1 else math.min(-1, math.min(arity1, arity2))
     case tp: WildcardType => -2
-    case tp: TypeVar if !tp.inst.exists => -2
+    case tp: TypeVar if !tp.isInstantiated => -2
     case _ =>
       if defn.isTupleNType(tp) then tp.dealias.argInfos.length
       else tp.dealias match
-        case tp: TypeVar if !tp.inst.exists => -2
+        case tp: TypeVar if !tp.isInstantiated => -2
         case _ => -1
 
   def normalizeClass(cls: ClassSymbol)(using Context): ClassSymbol = {
@@ -660,8 +660,8 @@ class TypeErasure(sourceLanguage: SourceLanguage, semiEraseVCs: Boolean, isConst
       erasePolyFunctionApply(refinedInfo)
     case RefinedType(parent, nme.apply, refinedInfo: MethodType) if defn.isErasedFunctionType(parent) =>
       eraseErasedFunctionApply(refinedInfo)
-    case tp: TypeVar if !tp.inst.exists =>
-      assert(inSigName, i"Cannot erase non-permanently instantiated type variable $tp")
+    case tp: TypeVar if !tp.isInstantiated =>
+      assert(inSigName, i"Cannot erase uninstantiated type variable $tp")
       null
     case tp: TypeProxy =>
       this(tp.underlying)
@@ -945,7 +945,7 @@ class TypeErasure(sourceLanguage: SourceLanguage, semiEraseVCs: Boolean, isConst
         sigName(underlyingOfTermRef(tp))
       case ExprType(rt) =>
         sigName(defn.FunctionOf(Nil, rt))
-      case tp: TypeVar if !tp.inst.exists =>
+      case tp: TypeVar if !tp.isInstantiated =>
         tpnme.Uninstantiated
       case tp @ RefinedType(parent, nme.apply, _) if parent.typeSymbol eq defn.PolyFunctionClass =>
         // we need this case rather than falling through to the default

Diff for: compiler/src/dotty/tools/dotc/core/Types.scala

@@ -2263,7 +2263,7 @@ object Types {
 
       if ctx.runId != mySignatureRunId then
         mySignature = computeSignature
-        if !mySignature.isUnderDefined then mySignatureRunId = ctx.runId
+        if !mySignature.isUnderDefined && !isProvisional then mySignatureRunId = ctx.runId
       mySignature
     end signature
 
@@ -3765,17 +3765,17 @@ object Types {
         case SourceLanguage.Java =>
           if ctx.runId != myJavaSignatureRunId then
             myJavaSignature = computeSignature
-            if !myJavaSignature.isUnderDefined then myJavaSignatureRunId = ctx.runId
+            if !myJavaSignature.isUnderDefined && !isProvisional then myJavaSignatureRunId = ctx.runId
           myJavaSignature
         case SourceLanguage.Scala2 =>
           if ctx.runId != myScala2SignatureRunId then
             myScala2Signature = computeSignature
-            if !myScala2Signature.isUnderDefined then myScala2SignatureRunId = ctx.runId
+            if !myScala2Signature.isUnderDefined && !isProvisional then myScala2SignatureRunId = ctx.runId
           myScala2Signature
         case SourceLanguage.Scala3 =>
           if ctx.runId != mySignatureRunId then
             mySignature = computeSignature
-            if !mySignature.isUnderDefined then mySignatureRunId = ctx.runId
+            if !mySignature.isUnderDefined && !isProvisional then mySignatureRunId = ctx.runId
           mySignature
     end signature