Performance improvements, particularly for deeply nested shapes.

src/main/java/com/tang/intellij/lua/codeInsight/inspection/AssignTypeInspection.kt

@@ -43,7 +43,7 @@ class AssignTypeInspection : StrictInspection() {
                         // Get owner class
                         val assigneeOwnerType = assignee.guessParentType(context)
 
-                        if (assigneeOwnerType is TyTable && resolvedValue is TyTable && assigneeOwnerType.table == resolvedValue.table) {
+                        if (assigneeOwnerType is TyTable && resolvedValue is TyTable && assigneeOwnerType.psi == resolvedValue.psi) {
                             return
                         }
 
@@ -87,7 +87,7 @@ class AssignTypeInspection : StrictInspection() {
 
                         val variableType = assignee.guessType(context)
 
-                        if (variableType == null || (variableType is TyTable && resolvedValue is TyTable && variableType.table == resolvedValue.table)) {
+                        if (variableType == null || (variableType is TyTable && resolvedValue is TyTable && variableType.psi == resolvedValue.psi)) {
                             return
                         }
 

src/main/java/com/tang/intellij/lua/comment/psi/impl/LuaCommentImpl.kt

@@ -182,6 +182,8 @@ class LuaCommentImpl(node: ASTNode) : ASTWrapperPsiElement(node), LuaComment {
             val map = list.associateBy { it.varName }
 
             object : TySubstitutor() {
+                override val name = "name substitutor"
+
                 override fun substitute(context: SearchContext, clazz: ITyClass): ITy {
                     return map[clazz.className] ?: super.substitute(context, clazz)
                 }

src/main/java/com/tang/intellij/lua/psi/LuaParamInfo.kt

@@ -23,7 +23,10 @@ import com.tang.intellij.lua.Constants
 import com.tang.intellij.lua.search.SearchContext
 import com.tang.intellij.lua.stubs.readTyNullable
 import com.tang.intellij.lua.stubs.writeTyNullable
-import com.tang.intellij.lua.ty.*
+import com.tang.intellij.lua.ty.ITy
+import com.tang.intellij.lua.ty.ITySubstitutor
+import com.tang.intellij.lua.ty.Primitives
+import com.tang.intellij.lua.ty.TyMultipleResults
 
 /**
  * parameter info
@@ -36,14 +39,14 @@ class LuaParamInfo(val name: String, val ty: ITy?) {
         return other is LuaParamInfo && other.ty == ty
     }
 
-    fun equals(context: SearchContext, other: LuaParamInfo): Boolean {
+    fun equals(context: SearchContext, other: LuaParamInfo, equalityFlags: Int): Boolean {
         if (ty == null) {
             return other.ty == null
         } else if (other.ty == null) {
             return false
         }
 
-        return ty.equals(context, other.ty)
+        return ty.equals(context, other.ty, equalityFlags)
     }
 
     override fun hashCode(): Int {

src/main/java/com/tang/intellij/lua/psi/LuaScopedTypeTree.kt

@@ -153,7 +153,7 @@ private class ScopedTypeTreeScope(override val psi: LuaTypeScope, override val t
             val classTag = if (cls is TySerializedClass) {
                 LuaClassIndex.find(context, cls.className)
             } else if (cls is TyPsiDocClass) {
-                cls.tagClass
+                cls.psi
             } else null
 
             // Need to ensure we don't check the same scope *without* beforeIndex

src/main/java/com/tang/intellij/lua/psi/PsiExtension.kt

@@ -104,9 +104,8 @@ private fun LuaExpression<*>.shouldBeInternal(context: SearchContext): ITy? {
                 var ret: ITy = Primitives.VOID
                 Ty.eachResolved(context, fTy) {
                     if (it is ITyFunction) {
-                        var sig = it.matchSignature(context, p2)?.substitutedSignature ?: it.mainSignature
-                        val substitutor = p2.createSubstitutor(context, sig)
-                        sig = sig.substitute(context, substitutor)
+                        val sig = it.matchSignature(context, p2)?.substitutedSignature
+                            ?: it.mainSignature.substitute(context, p2.createSubstitutor(context, it.mainSignature))
                         ret = ret.union(context, sig.getArgTy(idx))
                     }
                 }

src/main/java/com/tang/intellij/lua/ty/ProblemUtil.kt

@@ -90,6 +90,12 @@ object ProblemUtil {
             return false
         }
 
+        // We perform a non-structural (i.e. inheritance) check first as a happy path optimization. This is a *very*
+        // significant optimization when you've deeply nested shapes whose members are other (non-anonymous) shapes.
+        if (target.contravariantOf(context, source, varianceFlags or TyVarianceFlags.NON_STRUCTURAL)) {
+            return true;
+        }
+
         val sourceSubstitutor = source.getMemberSubstitutor(context)
         val targetSubstitutor = target.getMemberSubstitutor(context)
 
@@ -204,7 +210,7 @@ object ProblemUtil {
             val targetMemberTy = (if (indexTy != null) {
                 val targetMember = target.findIndexer(context, indexTy)
 
-                if (targetMember?.guessIndexType(context)?.equals(context, indexTy) == true) {
+                if (targetMember?.guessIndexType(context)?.equals(context, indexTy, 0) == true) {
                     // If the target index type == source index type, then we have already checked compatibility of this member above.
                     return@processMembers true
                 }
@@ -232,7 +238,7 @@ object ProblemUtil {
             // TODO: DRY
             if (varianceFlags and TyVarianceFlags.STRICT_UNKNOWN != 0 || !sourceMemberTy.isUnknown) {
                 if (varianceFlags and TyVarianceFlags.WIDEN_TABLES == 0) {
-                    if (!targetMemberTy.equals(context, sourceMemberTy)) {
+                    if (!targetMemberTy.equals(context, sourceMemberTy, 0)) {
                         isContravariant = false
 
                         if (processProblem != null && sourceElement != null) {
@@ -311,7 +317,7 @@ object ProblemUtil {
                 resolvedSourceTy.lazyInit(context)
 
                 if ((varianceFlags and TyVarianceFlags.NON_STRUCTURAL == 0 || resolvedSourceTy.isAnonymousTable) && resolvedSourceTy.isShape(context)) {
-                    val sourceIsInline = resolvedSourceTy is TyTable && resolvedSourceTy.table == sourceElement
+                    val sourceIsInline = resolvedSourceTy is TyTable && resolvedSourceTy.psi == sourceElement
                     val indexes = sortedMapOf<Int, PsiElement>()
                     var foundNumberIndexer = false
 
@@ -453,7 +459,7 @@ object ProblemUtil {
             base.lazyInit(context)
         }
 
-        if (varianceFlags and TyVarianceFlags.NON_STRUCTURAL == 0 && resolvedSourceTy is TyTable && resolvedSourceTy.table == sourceElement && base.isShape(context)) {
+        if (varianceFlags and TyVarianceFlags.NON_STRUCTURAL == 0 && resolvedSourceTy is TyTable && resolvedSourceTy.psi == sourceElement && base.isShape(context)) {
             isContravariant = contravariantOfShape(
                 context,
                 resolvedTargetTy,

src/main/java/com/tang/intellij/lua/ty/Ty.kt

@@ -29,9 +29,11 @@ import com.tang.intellij.lua.codeInsight.inspection.MatchFunctionSignatureInspec
 import com.tang.intellij.lua.ext.recursionGuard
 import com.tang.intellij.lua.project.LuaSettings
 import com.tang.intellij.lua.psi.LuaCallExpr
+import com.tang.intellij.lua.psi.LuaPsiElement
 import com.tang.intellij.lua.psi.LuaTableExpr
 import com.tang.intellij.lua.psi.argList
 import com.tang.intellij.lua.search.SearchContext
+import conditionallyCached
 import kotlin.contracts.ExperimentalContracts
 import kotlin.contracts.contract
 
@@ -68,6 +70,7 @@ class TyFlags {
         const val UNKNOWN = 0x20 // Unless STRICT_UNKNOWN is enabled, this type is covariant of all other types.
     }
 }
+
 class TyVarianceFlags {
     companion object {
         const val STRICT_UNKNOWN = 0x1 // When enabled UNKNOWN types are no longer treated as covariant of all types.
@@ -78,10 +81,28 @@ class TyVarianceFlags {
     }
 }
 
+class TyEqualityFlags {
+    companion object {
+        const val NON_STRUCTURAL = 0x1 // Treat shapes as classes i.e. a shape is only covariant of another shape if it explicitly inherits from it.
+
+        fun fromVarianceFlags(varianceFlags: Int): Int {
+            return if (varianceFlags and TyVarianceFlags.NON_STRUCTURAL != 0) {
+                TyEqualityFlags.NON_STRUCTURAL
+            } else {
+                0
+            }
+        }
+    }
+}
+
 data class SignatureMatchResult(val signature: IFunSignature?, val substitutedSignature: IFunSignature?, val returnTy: ITy)
 
 typealias ProcessTypeMember = (ownerTy: ITy, member: TypeMember) -> Boolean
 
+interface IPsiTy<T : LuaPsiElement> {
+    val psi: T
+}
+
 interface ITy : Comparable<ITy> {
     val kind: TyKind
 
@@ -91,7 +112,7 @@ interface ITy : Comparable<ITy> {
 
     val booleanType: ITy
 
-    fun equals(context: SearchContext, other: ITy): Boolean
+    fun equals(context: SearchContext, other: ITy, equalityFlags: Int): Boolean
 
     fun union(context: SearchContext, ty: ITy): ITy
 
@@ -501,8 +522,9 @@ abstract class Ty(override val kind: TyKind) : ITy {
 
     final override var flags: Int = 0
 
-    override val displayName: String
-        get() = TyRenderer.SIMPLE.render(this)
+    override val displayName by conditionallyCached({ !(this is IPsiTy<*>) || !SearchContext.get(psi.project).isDumb }) {
+        TyRenderer.SIMPLE.render(this)
+    }
 
     // Lazy initialization because Primitives.TRUE is itself a Ty that needs to be instantiated and refers to itself.
     override val booleanType: ITy by lazy { Primitives.TRUE }
@@ -548,7 +570,19 @@ abstract class Ty(override val kind: TyKind) : ITy {
 
         val resolvedOther = resolve(context, other)
 
-        if (this.equals(context, resolvedOther)) {
+        if (varianceFlags and TyVarianceFlags.NON_STRUCTURAL == 0 && isShape(context)) {
+            val isContravariant: Boolean? = recursionGuard(resolvedOther, {
+                // Note: ProblemUtil.contravariantOfShape will call back into this method with
+                //       TyVarianceFlags.NON_STRUCTURAL set as a fast nominal check, before checking structurally.
+                ProblemUtil.contravariantOfShape(context, this, resolvedOther, varianceFlags)
+            })
+
+            if (isContravariant != null) {
+                return isContravariant
+            }
+        }
+
+        if (this.equals(context, resolvedOther, TyEqualityFlags.fromVarianceFlags(varianceFlags))) {
             return true
         }
 
@@ -566,16 +600,6 @@ abstract class Ty(override val kind: TyKind) : ITy {
             return true
         }
 
-        if ((varianceFlags and TyVarianceFlags.NON_STRUCTURAL == 0 || other.isAnonymousTable) && isShape(context)) {
-            val isContravariant: Boolean? = recursionGuard(resolvedOther, {
-                ProblemUtil.contravariantOfShape(context, this, resolvedOther, varianceFlags)
-            })
-
-            if (isContravariant != null) {
-                return isContravariant
-            }
-        }
-
         val otherSuper = other.getSuperType(context)
         return otherSuper != null && contravariantOf(context, otherSuper, varianceFlags)
     }
@@ -871,7 +895,7 @@ class TyUnknown : Ty(TyKind.Unknown) {
         this.flags = this.flags or TyFlags.UNKNOWN
     }
 
-    override fun equals(context: SearchContext, other: ITy): Boolean {
+    override fun equals(context: SearchContext, other: ITy, equalityFlags: Int): Boolean {
         if (other === Primitives.UNKNOWN) {
             return true
         }
@@ -904,7 +928,7 @@ class TyNil : Ty(TyKind.Nil) {
 
     override val booleanType = Primitives.FALSE
 
-    override fun equals(context: SearchContext, other: ITy): Boolean {
+    override fun equals(context: SearchContext, other: ITy, equalityFlags: Int): Boolean {
         if (other === Primitives.NIL) {
             return true
         }
@@ -931,7 +955,7 @@ class TyNil : Ty(TyKind.Nil) {
 
 class TyVoid : Ty(TyKind.Void) {
 
-    override fun equals(context: SearchContext, other: ITy): Boolean {
+    override fun equals(context: SearchContext, other: ITy, equalityFlags: Int): Boolean {
         if (other === Primitives.VOID) {
             return true
         }

src/main/java/com/tang/intellij/lua/ty/TyAlias.kt

@@ -53,12 +53,12 @@ class TyAlias(override val name: String,
         return other is ITyAlias && other.name == name && other.flags == flags
     }
 
-    override fun equals(context: SearchContext, other: ITy): Boolean {
+    override fun equals(context: SearchContext, other: ITy, equalityFlags: Int): Boolean {
         if (this === other) {
             return true
         }
 
-        return ty.equals(context, other)
+        return ty.equals(context, other, equalityFlags)
     }
 
     override fun hashCode(): Int {

src/main/java/com/tang/intellij/lua/ty/TyArray.kt

@@ -31,13 +31,13 @@ open class TyArray(override val base: ITy) : Ty(TyKind.Array), ITyArray {
         return other is ITyArray && base == other.base
     }
 
-    override fun equals(context: SearchContext, other: ITy): Boolean {
+    override fun equals(context: SearchContext, other: ITy, equalityFlags: Int): Boolean {
         if (this === other) {
             return true
         }
 
         val resolvedOther = Ty.resolve(context, other)
-        return resolvedOther is ITyArray && base.equals(context, resolvedOther.base)
+        return resolvedOther is ITyArray && base.equals(context, resolvedOther.base, equalityFlags)
     }
 
     override fun hashCode(): Int {
@@ -56,7 +56,7 @@ open class TyArray(override val base: ITy) : Ty(TyKind.Array), ITyArray {
         val resolvedBase = Ty.resolve(context, base)
 
         if (other is ITyArray) {
-            return resolvedBase.equals(context, other.base)
+            return resolvedBase.equals(context, other.base, TyEqualityFlags.fromVarianceFlags(varianceFlags))
                     || (varianceFlags and TyVarianceFlags.WIDEN_TABLES != 0 && resolvedBase.contravariantOf(context, other.base, varianceFlags))
         }
 
@@ -88,7 +88,7 @@ open class TyArray(override val base: ITy) : Ty(TyKind.Array), ITyArray {
         }
 
         return varianceFlags and TyVarianceFlags.WIDEN_TABLES != 0
-                || Ty.resolve(context, resolvedBase).equals(context, indexedMemberType)
+                || Ty.resolve(context, resolvedBase).equals(context, indexedMemberType, TyEqualityFlags.fromVarianceFlags(varianceFlags))
                 || (resolvedBase.isUnknown && varianceFlags and TyVarianceFlags.STRICT_UNKNOWN == 0)
     }
 
@@ -185,14 +185,14 @@ object TyArraySerializer : TySerializer<ITyArray>() {
     }
 }
 
-class TyDocArray(val luaDocArrTy: LuaDocArrTy, base: ITy = luaDocArrTy.ty.getType()) : TyArray(base) {
+class TyDocArray(override val psi: LuaDocArrTy, base: ITy = psi.ty.getType()) : TyArray(base), IPsiTy<LuaDocArrTy> {
     override fun processIndexer(context: SearchContext, indexTy: ITy, exact: Boolean, deep: Boolean, process: ProcessTypeMember): Boolean {
         if (exact) {
-            if (Primitives.NUMBER.equals(context, indexTy)) {
-                return process(this, luaDocArrTy)
+            if (Primitives.NUMBER.equals(context, indexTy, 0)) {
+                return process(this, psi)
             }
         } else if (Primitives.NUMBER.contravariantOf(context, indexTy, TyVarianceFlags.STRICT_UNKNOWN)) {
-            return process(this, luaDocArrTy)
+            return process(this, psi)
         }
 
         return true
@@ -202,7 +202,7 @@ class TyDocArray(val luaDocArrTy: LuaDocArrTy, base: ITy = luaDocArrTy.ty.getTyp
         val substitutedBase = TyMultipleResults.getResult(context, base.substitute(context, substitutor))
 
         return if (substitutedBase !== base) {
-            TyDocArray(luaDocArrTy, substitutedBase)
+            TyDocArray(psi, substitutedBase)
         } else {
             this
         }