feat(completion): show self type fields/methods in completion list (#262)

With auto-insertion of `self.` prefix on select

Fixes #70

Author: i582

server/src/e2e/suite/testcases/completion/methods.test

@@ -19,3 +19,50 @@ fun test() {
 14 let  Create variable
 14 not  Negate expression
 14 repeat  Create repeat loop
+
+========================================================================
+Completion of struct field of self type
+========================================================================
+primitive Int;
+
+struct Data {
+    active: Bool;
+}
+
+extends fun some(self: Data) {
+    return <caret>
+}
+------------------------------------------------------------------------
+5  self   Data
+9  self.active:    of Data
+13 false
+13 initOf Contract(params)   StateInit
+13 null
+13 true
+2  some(self: Data)
+21 Data{}
+
+========================================================================
+Completion of struct method of self type
+========================================================================
+primitive Int;
+
+struct Data {
+    active: Bool;
+}
+
+extends fun other(self: Data) {}
+
+extends fun some(self: Data) {
+    return <caret>
+}
+------------------------------------------------------------------------
+5  self   Data
+9  self.active:    of Data
+13 false
+13 initOf Contract(params)   StateInit
+13 null
+13 true
+2  other(self: Data)
+2  some(self: Data)
+21 Data{}

server/src/e2e/suite/testcases/completion/variables.test

@@ -82,6 +82,7 @@ extends fun move(self: Point, x: Int, y: Int) {
 13 null
 13 return;
 13 true
+2  move(self: Point, x: Int, y: Int)
 21 Point{}
 14 do
 14 foreach
@@ -114,6 +115,7 @@ extends fun scale(self: Point, factor: Int) {
 13 null
 13 return;
 13 true
+2  scale(self: Point, factor: Int)
 21 Point{}
 14 do
 14 foreach

server/src/psi/Decls.ts

@@ -291,6 +291,14 @@ export class Fun extends NamedNode {
         return first.name() === "self"
     }
 
+    public selfParam(): NamedNode | null {
+        const params = this.parameters()
+        if (params.length === 0) return null
+        const first = params[0]
+        if (first.name() !== "self") return null
+        return first
+    }
+
     public signaturePresentation(): string {
         const parametersNode = this.node.childForFieldName("parameters")
         if (!parametersNode) return ""

server/src/psi/Reference.ts

@@ -315,21 +315,25 @@ export class Reference {
             }
         }
 
-        // inside a trait/contract, when we write `foo`, we want to automatically complete it
-        // with `self.foo` if there are any methods/fields/constants with the same name
-        const ownerNode = parentOfType(this.element.node, "contract_body", "trait_body")
-        if (ownerNode !== null && state.get("completion")) {
-            const constructor = ownerNode.type === "contract_body" ? Contract : Trait
-            const parent = ownerNode.parent
-            if (!parent) return true
-
-            const owner = new constructor(parent, this.element.file)
-            const typeConstructor = ownerNode.type === "contract_body" ? ContractTy : TraitTy
-            const ownerTy = new typeConstructor(owner.name(), owner)
-            const expr = new Expression(this.element.node, this.element.file)
+        if (state.get("completion")) {
+            const ownerNode = parentOfType(
+                this.element.node,
+                "contract_body",
+                "trait_body",
+                "global_function",
+            )
+
+            // inside a trait/contract, when we write `foo`, we want to automatically complete it
+            // with `self.foo` if there are any methods/fields/constants with the same name
+            if (ownerNode?.type === "contract_body" || ownerNode?.type === "trait_body") {
+                if (!this.processContractTraitSelfCompletion(ownerNode, state, proc)) return false
+            }
 
-            const newState = state.withValue("prefix", "self.")
-            if (!this.processType(expr, ownerTy, proc, newState)) return false
+            // inside extends function, when we write `foo`, we want to automatically complete it
+            // with `self.foo` if there are any methods/fields/constants with the same name
+            if (ownerNode?.type === "global_function") {
+                if (!this.processExtendsMethodSelfCompletion(ownerNode, state, proc)) return false
+            }
         }
 
         if (this.element.node.type === "tvm_instruction") {
@@ -369,6 +373,41 @@ export class Reference {
         return this.processAllEntities(proc, state)
     }
 
+    private processContractTraitSelfCompletion(
+        ownerNode: SyntaxNode,
+        state: ResolveState,
+        proc: ScopeProcessor,
+    ): boolean {
+        const constructor = ownerNode.type === "contract_body" ? Contract : Trait
+        const parent = ownerNode.parent
+        if (!parent) return true
+
+        const owner = new constructor(parent, this.element.file)
+        const typeConstructor = ownerNode.type === "contract_body" ? ContractTy : TraitTy
+        const ownerTy = new typeConstructor(owner.name(), owner)
+        const expr = new Expression(this.element.node, this.element.file)
+
+        const newState = state.withValue("prefix", "self.")
+        return this.processType(expr, ownerTy, proc, newState)
+    }
+
+    private processExtendsMethodSelfCompletion(
+        ownerNode: SyntaxNode,
+        state: ResolveState,
+        proc: ScopeProcessor,
+    ): boolean {
+        const func = new Fun(ownerNode, this.element.file)
+        const selfParam = func.selfParam()
+        if (selfParam === null) return true // skip if we are not in extends function
+
+        const selfTy = TypeInferer.inferType(selfParam)
+        if (!selfTy) return true
+        const expr = new Expression(this.element.node, this.element.file)
+
+        const newState = state.withValue("prefix", "self.")
+        return this.processType(expr, selfTy, proc, newState)
+    }
+
     private resolveInstanceInitField(
         parent: SyntaxNode,
         proc: ScopeProcessor,