Ensure global classes (i.e. built-ins) can be extended.

Closes #55

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

@@ -26,7 +26,6 @@ import com.tang.intellij.lua.psi.LuaCallExpr
 import com.tang.intellij.lua.psi.LuaExpression
 import com.tang.intellij.lua.psi.LuaIndexExpr
 import com.tang.intellij.lua.psi.LuaVisitor
-import com.tang.intellij.lua.search.ProjectSearchContext
 import com.tang.intellij.lua.search.PsiSearchContext
 import com.tang.intellij.lua.search.SearchContext
 import com.tang.intellij.lua.ty.*

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

@@ -35,7 +35,7 @@ class UndeclaredMemberInspection : StrictInspection() {
                     val memberName = o.name
 
                     Ty.eachResolved(context, prefix) { prefixTy ->
-                        if (!prefixTy.isGlobal && !(prefixTy.isUnknown && LuaSettings.instance.isUnknownIndexable)) {
+                        if ((!prefixTy.isGlobal && !prefixTy.isUnknown) || !LuaSettings.instance.isUnknownIndexable) {
                             if (memberName != null) {
                                 if (prefixTy.guessMemberType(context, memberName) == null) {
                                     myHolder.registerProblem(o, "No such member '%s' found on type '%s'".format(memberName, prefixTy))

src/main/java/com/tang/intellij/lua/lang/LuaLanguage.java

@@ -24,7 +24,7 @@
  */
 public class LuaLanguage extends Language {
 
-    public static final int INDEX_VERSION = 70;
+    public static final int INDEX_VERSION = 71;
 
     public static final LuaLanguage INSTANCE = new LuaLanguage();
 

src/main/java/com/tang/intellij/lua/stubs/LuaClassMethodDefStatStub.kt

@@ -52,11 +52,6 @@ class LuaClassMethodType : LuaStubElementType<LuaClassMethodDefStatStub, LuaClas
             }
         }
 
-        if (classNameSet.isEmpty()) {
-            classNameSet.add(createSerializedClass(expr.text))
-        }
-
-
         val visibility = def.visibility
         val isStatic = methodName.dot != null
         val isDeprecated = def.isDeprecated

src/main/java/com/tang/intellij/lua/stubs/LuaDocTagClassStub.kt

@@ -116,6 +116,6 @@ class LuaDocTagClassStubImpl(override val className: String,
     override val classType: TyClass
         get() {
             val flags = if (isShape) TyFlags.SHAPE else 0
-            return createSerializedClass(className, params, className, superClass, signatures, aliasName, flags)
+            return createSerializedClass(className, params, null, superClass, signatures, aliasName, flags)
         }
 }

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

@@ -378,7 +378,7 @@ private fun LuaNameExpr.infer(context: SearchContext): ITy? {
             }
         }
 
-        withSearchGuard(this) {
+        var ty = withSearchGuard(this) {
             val multiResolve = multiResolve(context, this)
             var maxTimes = 10
 
@@ -400,6 +400,19 @@ private fun LuaNameExpr.infer(context: SearchContext): ITy? {
 
             type
         } ?: getType(context, this)
+
+        // Global
+        if (ty == null && context.isDumb && this.isGlobal()) {
+            // In order to facilitate the extension of globals without needing to *explicitly* refer to the
+            // underlying global variable's class by name. Since we can't look up / resolve the global's variable's
+            // type during indexing, we instead attach members to a global type (identified by variable name). When
+            // we process a class' members later, we also process against its aliasName i.e. name of global variable.
+            // NOTE: We only need to hit this code path in "dumb mode" (i.e. during stub indexing) since that's where
+            //       we create/index class members. All other times, we'll leave the ty as nil (unknown).
+            ty = TyClass.createGlobalType(this)
+        }
+
+        ty
     })
 }
 
@@ -429,26 +442,17 @@ private fun getType(context: SearchContext, def: PsiElement): ITy? {
                     }
                 }
             }
-
-            //Global
-            if (type != null && isGlobal(def) && def.docTy == null && type !is ITyPrimitive) {
-                // Explicitly instantiating a union (not calling the type.union()) as the global type resolves to type,
-                // and hence we would have just got type back. We're creating a union because we need to ensure members
-                // are indexed against the global name (for completion) as well as the other type (for type resolution).
-                type = TyUnion(listOf(type, TyClass.createGlobalType(def)))
-            }
-
             type
         }
         is LuaPsiTypeGuessable -> def.guessType(context)
         else -> null
     }
 }
 
-private fun isGlobal(nameExpr: LuaNameExpr): Boolean {
-    val minx = nameExpr as LuaNameExprMixin
-    val gs = minx.greenStub
-    return gs?.isGlobal ?: (resolveLocal(null, nameExpr) == null)
+fun LuaNameExpr.isGlobal(): Boolean {
+    val mixin = this as LuaNameExprMixin
+    val greenStub = mixin.greenStub
+    return greenStub?.isGlobal ?: (resolveLocal(null, this) == null)
 }
 
 fun LuaLiteralExpr.infer(): ITy {

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

@@ -588,7 +588,7 @@ abstract class Ty(override val kind: TyKind) : ITy {
     override fun toString() = displayName
 
     override fun contravariantOf(context: SearchContext, other: ITy, varianceFlags: Int): Boolean {
-        if ((other.kind == TyKind.Unknown && varianceFlags and TyVarianceFlags.STRICT_UNKNOWN == 0)
+        if (((other.kind == TyKind.Unknown || other.isGlobal) && varianceFlags and TyVarianceFlags.STRICT_UNKNOWN == 0)
             || (other.kind == TyKind.Nil && varianceFlags and TyVarianceFlags.STRICT_NIL == 0 && !LuaSettings.instance.isNilStrict)
         ) {
             return true

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

@@ -38,7 +38,7 @@ import com.tang.intellij.lua.stubs.*
 
 interface ITyClass : ITyResolvable {
     val className: String
-    val varName: String
+    val varName: String?
 
     var superClass: ITy?
     var aliasName: String?
@@ -168,7 +168,7 @@ private fun equalToShape(context: SearchContext, target: ITy, source: ITy): Bool
 
 abstract class TyClass(override val className: String,
                        override var params: Array<TyGenericParameter>? = null,
-                       override val varName: String = "",
+                       override val varName: String? = "",
                        override var superClass: ITy? = null,
                        override var signatures: Array<IFunSignature>? = null
 ) : Ty(TyKind.Class), ITyClass {
@@ -407,7 +407,7 @@ abstract class TyClass(override val className: String,
 class TyPsiDocClass(override val psi: LuaDocTagClass) : TyClass(
     psi.name,
     psi.genericDefList.map { TyGenericParameter(it) }.toTypedArray(),
-    "",
+    null,
     psi.superClass?.getType(),
     psi.overloads
 ), IPsiTy<LuaDocTagClass> {
@@ -425,7 +425,7 @@ class TyPsiDocClass(override val psi: LuaDocTagClass) : TyClass(
 
 open class TySerializedClass(name: String,
                              params: Array<TyGenericParameter>? = null,
-                             varName: String = name,
+                             varName: String? = null,
                              superClass: ITy? = null,
                              signatures: Array<IFunSignature>? = null,
                              alias: String? = null,
@@ -467,7 +467,7 @@ class TyLazyClass(name: String, val psi: PsiElement? = null) : TySerializedClass
 
 fun createSerializedClass(name: String,
                           params: Array<TyGenericParameter>? = null,
-                          varName: String = name,
+                          varName: String? = null,
                           superClass: ITy? = null,
                           signatures: Array<IFunSignature>? = null,
                           alias: String? = null,
@@ -619,7 +619,7 @@ fun getConcreteGenericParameterName(genericParam: TyGenericParameter): String {
 }
 
 fun getGlobalTypeName(text: String): String {
-    return if (text == Constants.WORD_G) text else "$$text"
+    return if (text == Constants.WORD_G) text else "${Constants.WORD_G}.$text"
 }
 
 fun getGlobalTypeName(nameExpr: LuaNameExpr): String {

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

@@ -30,7 +30,7 @@ fun genericParameterName(def: LuaDocGenericDef): String {
     return "${def.id.text}@${def.node.startOffset}@${def.containingFile.getFileIdentifier()}"
 }
 
-class TyGenericParameter(name: String, varName: String, superClass: ITy? = null) : TySerializedClass(name, emptyArray(), varName, superClass, null) {
+class TyGenericParameter(name: String, override val varName: String, superClass: ITy? = null) : TySerializedClass(name, emptyArray(), varName, superClass, null) {
     constructor(def: LuaDocGenericDef) : this(genericParameterName(def), def.id.text, def.superClass?.getType())
 
     override fun equals(other: Any?): Boolean {

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

@@ -332,10 +332,10 @@ open class TyRenderer : TyVisitor(), ITyRenderer {
             }
             clazz.isAnonymous -> {
                 if (isSuffixedClass(clazz)) {
-                    clazz.varName
-                } else {
-                    "[local ${clazz.varName}]"
+                    clazz.varName?.let { return it }
                 }
+
+                "[local ${clazz.varName}]"
             }
             clazz.isGlobal -> "[global ${clazz.varName}]"
             else -> "${clazz.className}${renderGenericParams(clazz.params?.map { it.toString() })}"

src/test/resources/inspections/global_definitions.lua

@@ -16,3 +16,10 @@ function GlobalAnonymousClass.doSomethingElse()
 end
 
 GlobalAnonymousClass.anotherNumber = 2
+
+--- Extend built-in global without explicitly referring to its type
+
+---@param a number
+function math.extension(a)
+    return a
+end

src/test/resources/inspections/global_usage.lua

@@ -16,5 +16,9 @@ aNumber = GlobalAnonymousClass.anotherNumber
 aString = <error descr="Type mismatch. Required: 'string' Found: 'number'">GlobalClass.someNumber</error>
 aString = <error descr="Type mismatch. Required: 'string' Found: 'number'">GlobalAnonymousClass.anotherNumber</error>
 
----@type number
 local fromStdLib = math.pi
+aNumber = fromStdLib
+aString = <error descr="Type mismatch. Required: 'string' Found: 'number'">fromStdLib</error>
+
+aNumber = math.extension(aNumber)
+aString = <error descr="Type mismatch. Required: 'string' Found: 'number'">math.extension(aNumber)</error>

src/test/resources/inspections/self.lua

@@ -28,7 +28,7 @@ end
 ---@return self
 function SelfA.dotMethod()
     ---@type self
-    local selfTypedVar = <warning descr="Undeclared variable 'self'.">self</warning>
+    local selfTypedVar
 
     ---@type SelfA
     local someSelfA
@@ -46,7 +46,7 @@ end
 ---@return self
 SelfA.lambdaMethod = function()
     ---@type self
-    local selfTypedVar = <warning descr="Undeclared variable 'self'.">self</warning>
+    local selfTypedVar
 
     ---@type SelfA
     local someSelfA