Fixes to isFunctionCallExternal() after end-to-end test (#215)

* Reintroduce isFunctionCallExternal() as method of InferType. Impoved detection of calls in external context. Added relevant cases to a test sample.

* Update dependencies

* Update test sample

* Fix few more edge cases to address failures of Scribble tests

* Fix review remarks

src/types/infer.ts

@@ -50,7 +50,7 @@ import {
     encodeFuncSignature,
     resolveAny
 } from "../ast";
-import { DataLocation } from "../ast/constants";
+import { DataLocation, ExternalReferenceType } from "../ast/constants";
 import { assert, eq, forAll, forAny, pp } from "../misc";
 import { ABIEncoderVersion, abiTypeToCanonicalName, abiTypeToLibraryCanonicalName } from "./abi";
 import {
@@ -98,6 +98,7 @@ import { TypeSubstituion, applySubstitution, buildSubstitutions } from "./polymo
 import { types } from "./reserved";
 import {
     BINARY_OPERATOR_GROUPS,
+    CALL_BUILTINS,
     SUBDENOMINATION_MULTIPLIERS,
     castable,
     decimalToRational,
@@ -2662,4 +2663,95 @@ export class InferType {
 
         return resolvedCalleeT;
     }
+
+    private isExternalCallContext(expr: Expression): boolean {
+        if (
+            expr instanceof Identifier ||
+            expr instanceof MemberAccess ||
+            expr instanceof FunctionCallOptions ||
+            expr instanceof FunctionCall
+        ) {
+            const exprT = this.typeOf(expr);
+
+            if (exprT instanceof UserDefinedType) {
+                if (exprT.definition instanceof ContractDefinition) {
+                    return true;
+                }
+            }
+
+            if (exprT instanceof TypeNameType) {
+                return (
+                    exprT.type instanceof UserDefinedType &&
+                    exprT.type.definition instanceof ContractDefinition &&
+                    exprT.type.definition.kind === ContractKind.Library
+                );
+            }
+        }
+
+        if (
+            expr instanceof MemberAccess ||
+            expr instanceof FunctionCallOptions ||
+            expr instanceof FunctionCall
+        ) {
+            return this.isExternalCallContext(expr.vExpression);
+        }
+
+        if (expr instanceof Conditional) {
+            return (
+                this.isExternalCallContext(expr.vTrueExpression) ||
+                this.isExternalCallContext(expr.vFalseExpression)
+            );
+        }
+
+        if (expr instanceof TupleExpression && expr.vComponents.length === 1) {
+            return this.isExternalCallContext(expr.vComponents[0]);
+        }
+
+        return false;
+    }
+
+    isFunctionCallExternal(call: FunctionCall): boolean {
+        if (call.kind !== FunctionCallKind.FunctionCall) {
+            return false;
+        }
+
+        if (
+            call.vFunctionCallType === ExternalReferenceType.Builtin &&
+            CALL_BUILTINS.includes(call.vFunctionName)
+        ) {
+            return true;
+        }
+
+        let exprT = this.typeOf(call.vExpression);
+
+        if (exprT instanceof FunctionLikeSetType) {
+            const calleeT = this.typeOfCallee(call);
+
+            if (!(calleeT instanceof FunctionType)) {
+                return false;
+            }
+
+            exprT = calleeT;
+        }
+
+        if (exprT instanceof FunctionType) {
+            if (exprT.implicitFirstArg) {
+                /**
+                 * Calls via using-for are not considered as external.
+                 * Currently "implicitFirstArg" is used only for using-for.
+                 */
+                return false;
+            }
+
+            if (exprT.visibility === FunctionVisibility.External) {
+                return true;
+            }
+
+            if (exprT.visibility === FunctionVisibility.Public) {
+                return this.isExternalCallContext(call.vExpression);
+            }
+        }
+
+        return false;
+    }
 }

src/types/utils.ts

@@ -7,22 +7,18 @@ import {
     ErrorDefinition,
     EventDefinition,
     Expression,
-    ExternalReferenceType,
-    FunctionCall,
-    FunctionCallKind,
     FunctionDefinition,
     FunctionKind,
     FunctionStateMutability,
     FunctionVisibility,
-    MemberAccess,
     ModifierDefinition,
     SourceUnit,
     StructDefinition,
     TupleExpression,
     VariableDeclaration
 } from "../ast";
 import { assert, eq, forAll, forAny } from "../misc";
-import { InferType, types } from "../types";
+import { types } from "../types";
 import { ABIEncoderVersion } from "./abi";
 import {
     AddressType,
@@ -317,49 +313,6 @@ export function getABIEncoderVersion(unit: SourceUnit, compilerVersion: string):
     return lt(compilerVersion, "0.8.0") ? ABIEncoderVersion.V1 : ABIEncoderVersion.V2;
 }
 
-export function isFunctionCallExternal(call: FunctionCall, inference: InferType): boolean {
-    if (call.kind !== FunctionCallKind.FunctionCall) {
-        return false;
-    }
-
-    if (
-        call.vFunctionCallType === ExternalReferenceType.Builtin &&
-        CALL_BUILTINS.includes(call.vFunctionName)
-    ) {
-        return true;
-    }
-
-    const exprT = inference.typeOf(call.vExpression);
-
-    if (exprT instanceof FunctionType) {
-        if (exprT.implicitFirstArg) {
-            /**
-             * Calls via using-for are not considered as external.
-             * Currently "implicitFirstArg" is used only for using-for.
-             */
-            return false;
-        }
-
-        if (exprT.visibility === FunctionVisibility.External) {
-            return true;
-        }
-
-        if (exprT.visibility === FunctionVisibility.Public) {
-            /**
-             * We have external calls when call expression have pattern "expr.fun()",
-             * where "expr" is an identifier, "this" or an expression of ContractType.
-             *
-             * Other expressions, that are invoked via an identifier or struct type
-             * are requiring function type to have non-public visibility,
-             * so they are handled by other cases.
-             */
-            return call.vExpression.getChildrenByType(MemberAccess, true).length > 0;
-        }
-    }
-
-    return false;
-}
-
 export function getFallbackRecvFuns(contract: ContractDefinition): FunctionDefinition[] {
     const res: FunctionDefinition[] = [];