Baseline arity checks for jsx sfc tags

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Author: weswigham

src/compiler/checker.ts

@@ -939,6 +939,7 @@ namespace ts {
                     if (jsxPragma) {
                         const chosenpragma = isArray(jsxPragma) ? jsxPragma[0] : jsxPragma;
                         file.localJsxFactory = parseIsolatedEntityName(chosenpragma.arguments.factory, languageVersion);
+                        visitNode(file.localJsxFactory, markAsSynthetic);
                         if (file.localJsxFactory) {
                             return file.localJsxNamespace = getFirstIdentifier(file.localJsxFactory).escapedText;
                         }
@@ -949,6 +950,7 @@ namespace ts {
                 _jsxNamespace = "React" as __String;
                 if (compilerOptions.jsxFactory) {
                     _jsxFactoryEntity = parseIsolatedEntityName(compilerOptions.jsxFactory, languageVersion);
+                    visitNode(_jsxFactoryEntity, markAsSynthetic);
                     if (_jsxFactoryEntity) {
                         _jsxNamespace = getFirstIdentifier(_jsxFactoryEntity).escapedText;
                     }
@@ -957,7 +959,16 @@ namespace ts {
                     _jsxNamespace = escapeLeadingUnderscores(compilerOptions.reactNamespace);
                 }
             }
+            if (!_jsxFactoryEntity) {
+                _jsxFactoryEntity = createQualifiedName(createIdentifier(unescapeLeadingUnderscores(_jsxNamespace)), "createElement");
+            }
             return _jsxNamespace;
+
+            function markAsSynthetic(node: Node): VisitResult<Node> {
+                node.pos = -1;
+                node.end = -1;
+                return visitEachChild(node, markAsSynthetic, nullTransformationContext);
+            }
         }
 
         function getEmitResolver(sourceFile: SourceFile, cancellationToken: CancellationToken) {
@@ -2801,8 +2812,8 @@ namespace ts {
             const namespaceMeaning = SymbolFlags.Namespace | (isInJSFile(name) ? meaning & SymbolFlags.Value : 0);
             let symbol: Symbol | undefined;
             if (name.kind === SyntaxKind.Identifier) {
-                const message = meaning === namespaceMeaning ? Diagnostics.Cannot_find_namespace_0 : getCannotFindNameDiagnosticForName(getFirstIdentifier(name));
-                const symbolFromJSPrototype = isInJSFile(name) ? resolveEntityNameFromAssignmentDeclaration(name, meaning) : undefined;
+                const message = meaning === namespaceMeaning || nodeIsSynthesized(name) ? Diagnostics.Cannot_find_namespace_0 : getCannotFindNameDiagnosticForName(getFirstIdentifier(name));
+                const symbolFromJSPrototype = isInJSFile(name) && !nodeIsSynthesized(name) ? resolveEntityNameFromAssignmentDeclaration(name, meaning) : undefined;
                 symbol = resolveName(location || name, name.escapedText, meaning, ignoreErrors || symbolFromJSPrototype ? undefined : message, name, /*isUse*/ true);
                 if (!symbol) {
                     return symbolFromJSPrototype;
@@ -2845,7 +2856,7 @@ namespace ts {
                 throw Debug.assertNever(name, "Unknown entity name kind.");
             }
             Debug.assert((getCheckFlags(symbol) & CheckFlags.Instantiated) === 0, "Should never get an instantiated symbol here.");
-            if (isEntityName(name) && (symbol.flags & SymbolFlags.Alias || name.parent.kind === SyntaxKind.ExportAssignment)) {
+            if (!nodeIsSynthesized(name) && isEntityName(name) && (symbol.flags & SymbolFlags.Alias || name.parent.kind === SyntaxKind.ExportAssignment)) {
                 markSymbolOfAliasDeclarationIfTypeOnly(getAliasDeclarationFromName(name), symbol, /*finalTarget*/ undefined, /*overwriteEmpty*/ true);
             }
             return (symbol.flags & meaning) || dontResolveAlias ? symbol : resolveAlias(symbol);
@@ -24298,7 +24309,7 @@ namespace ts {
             // can be specified by users through attributes property.
             const paramType = getEffectiveFirstArgumentForJsxSignature(signature, node);
             const attributesType = checkExpressionWithContextualType(node.attributes, paramType, /*inferenceContext*/ undefined, checkMode);
-            return checkTypeRelatedToAndOptionallyElaborate(
+            return checkTagNameDoesNotExpectTooManyArguments() && checkTypeRelatedToAndOptionallyElaborate(
                 attributesType,
                 paramType,
                 relation,
@@ -24307,6 +24318,80 @@ namespace ts {
                 /*headMessage*/ undefined,
                 containingMessageChain,
                 errorOutputContainer);
+
+            function checkTagNameDoesNotExpectTooManyArguments(): boolean {
+                const tagType = isJsxOpeningElement(node) || isJsxSelfClosingElement(node) && !isJsxIntrinsicIdentifier(node.tagName) ? checkExpression(node.tagName) : undefined;
+                if (!tagType) {
+                    return true;
+                }
+                const tagCallSignatures = getSignaturesOfType(tagType, SignatureKind.Call);
+                if (!length(tagCallSignatures)) {
+                    return true;
+                }
+                const factory = getJsxFactoryEntity(node);
+                if (!factory) {
+                    return true;
+                }
+                const factorySymbol = resolveEntityName(factory, SymbolFlags.Value, /*ignoreErrors*/ true, /*dontResolveAlias*/ false, node);
+                if (!factorySymbol) {
+                    return true;
+                }
+
+                const factoryType = getTypeOfSymbol(factorySymbol);
+                const callSignatures = getSignaturesOfType(factoryType, SignatureKind.Call);
+                if (!length(callSignatures)) {
+                    return true;
+                }
+
+                let hasFirstParamSignatures = false;
+                let maxParamCount = 0;
+                // Check that _some_ first parameter expects a FC-like thing, and that some overload of the SFC expects an acceptable number of arguments
+                for (const sig of callSignatures) {
+                    const firstparam = getTypeAtPosition(sig, 0);
+                    const signaturesOfParam = getSignaturesOfType(firstparam, SignatureKind.Call);
+                    if (!length(signaturesOfParam)) continue;
+                    for (const paramSig of signaturesOfParam) {
+                        hasFirstParamSignatures = true;
+                        if (hasEffectiveRestParameter(paramSig)) {
+                            return true; // some signature has a rest param, so function components can have an arbitrary number of arguments
+                        }
+                        const paramCount = getParameterCount(paramSig);
+                        if (paramCount > maxParamCount) {
+                            maxParamCount = paramCount;
+                        }
+                    }
+                }
+                if (!hasFirstParamSignatures) {
+                    // Not a single signature had a first parameter which expected a signature - for back compat, and
+                    // to guard against generic factories which won't have signatures directly, do not error
+                    return true;
+                }
+                let absoluteMinArgCount = Infinity;
+                for (const tagSig of tagCallSignatures) {
+                    const tagRequiredArgCount = getMinArgumentCount(tagSig);
+                    if (tagRequiredArgCount < absoluteMinArgCount) {
+                        absoluteMinArgCount = tagRequiredArgCount;
+                    }
+                }
+                if (absoluteMinArgCount <= maxParamCount) {
+                    return true; // some signature accepts the number of arguments the function component provides
+                }
+
+                if (reportErrors) {
+                    const diag = createDiagnosticForNode(node.tagName, Diagnostics.Tag_0_expects_at_least_1_arguments_but_the_JSX_factory_2_provides_at_most_3, entityNameToString(node.tagName), absoluteMinArgCount, entityNameToString(factory), maxParamCount);
+                    const tagNameDeclaration = getSymbolAtLocation(node.tagName)?.valueDeclaration;
+                    if (tagNameDeclaration) {
+                        addRelatedInfo(diag, createDiagnosticForNode(tagNameDeclaration, Diagnostics._0_is_declared_here, entityNameToString(node.tagName)));
+                    }
+                    if (errorOutputContainer && errorOutputContainer.skipLogging) {
+                        (errorOutputContainer.errors || (errorOutputContainer.errors = [])).push(diag);
+                    }
+                    if (!errorOutputContainer.skipLogging) {
+                        diagnostics.add(diag);
+                    }
+                }
+                return false;
+            }
         }
 
         function getSignatureApplicabilityError(
@@ -35175,6 +35260,10 @@ namespace ts {
             return literalTypeToNode(<FreshableType>type, node, tracker);
         }
 
+        function getJsxFactoryEntity(location: Node) {
+            return location ? (getJsxNamespace(location), (getSourceFileOfNode(location).localJsxFactory || _jsxFactoryEntity)) : _jsxFactoryEntity;
+        }
+
         function createResolver(): EmitResolver {
             // this variable and functions that use it are deliberately moved here from the outer scope
             // to avoid scope pollution
@@ -35246,7 +35335,7 @@ namespace ts {
                     const symbol = node && getSymbolOfNode(node);
                     return !!(symbol && getCheckFlags(symbol) & CheckFlags.Late);
                 },
-                getJsxFactoryEntity: location => location ? (getJsxNamespace(location), (getSourceFileOfNode(location).localJsxFactory || _jsxFactoryEntity)) : _jsxFactoryEntity,
+                getJsxFactoryEntity,
                 getAllAccessorDeclarations(accessor: AccessorDeclaration): AllAccessorDeclarations {
                     accessor = getParseTreeNode(accessor, isGetOrSetAccessorDeclaration)!; // TODO: GH#18217
                     const otherKind = accessor.kind === SyntaxKind.SetAccessor ? SyntaxKind.GetAccessor : SyntaxKind.SetAccessor;

src/compiler/diagnosticMessages.json

@@ -4280,6 +4280,10 @@
         "category": "Message",
         "code": 6228
     },
+    "Tag '{0}' expects at least '{1}' arguments, but the JSX factory '{2}' provides at most '{3}'.": {
+        "category": "Error",
+        "code": 6229
+    },
 
     "Projects to reference": {
         "category": "Message",

src/compiler/utilities.ts

@@ -864,14 +864,17 @@ namespace ts {
         }
     }
 
-    export function entityNameToString(name: EntityNameOrEntityNameExpression): string {
+    export function entityNameToString(name: EntityNameOrEntityNameExpression | JsxTagNameExpression | PrivateIdentifier): string {
         switch (name.kind) {
+            case SyntaxKind.ThisKeyword:
+                return "this";
+            case SyntaxKind.PrivateIdentifier:
             case SyntaxKind.Identifier:
                 return getFullWidth(name) === 0 ? idText(name) : getTextOfNode(name);
             case SyntaxKind.QualifiedName:
                 return entityNameToString(name.left) + "." + entityNameToString(name.right);
             case SyntaxKind.PropertyAccessExpression:
-                if (isIdentifier(name.name)) {
+                if (isIdentifier(name.name) || isPrivateIdentifier(name.name)) {
                     return entityNameToString(name.expression) + "." + entityNameToString(name.name);
                 }
                 else {

tests/baselines/reference/jsxIssuesErrorWhenTagExpectsTooManyArguments.errors.txt

@@ -0,0 +1,35 @@
+tests/cases/compiler/jsxIssuesErrorWhenTagExpectsTooManyArguments.tsx(19,12): error TS6229: Tag 'MyComp4' expects at least '4' arguments, but the JSX factory 'React.createElement' provides at most '2'.
+tests/cases/compiler/jsxIssuesErrorWhenTagExpectsTooManyArguments.tsx(20,12): error TS6229: Tag 'MyComp3' expects at least '3' arguments, but the JSX factory 'React.createElement' provides at most '2'.
+
+
+==== tests/cases/compiler/jsxIssuesErrorWhenTagExpectsTooManyArguments.tsx (2 errors) ====
+    /// <reference path="/.lib/react16.d.ts" />
+    
+    import * as React from "react";
+    
+    interface MyProps {
+        x: number;
+    }
+    
+    function MyComp4(props: MyProps, context: any, bad: any, verybad: any) {
+        return <div></div>;
+    }
+    function MyComp3(props: MyProps, context: any, bad: any) {
+        return <div></div>;
+    }
+    function MyComp2(props: MyProps, context: any) {
+        return <div></div>
+    }
+    
+    const a = <MyComp4 x={2}/>; // using `MyComp` as a component should error - it expects more arguments than react provides
+               ~~~~~~~
+!!! error TS6229: Tag 'MyComp4' expects at least '4' arguments, but the JSX factory 'React.createElement' provides at most '2'.
+!!! related TS2728 tests/cases/compiler/jsxIssuesErrorWhenTagExpectsTooManyArguments.tsx:9:10: 'MyComp4' is declared here.
+    const b = <MyComp3 x={2}/>; // using `MyComp` as a component should error - it expects more arguments than react provides
+               ~~~~~~~
+!!! error TS6229: Tag 'MyComp3' expects at least '3' arguments, but the JSX factory 'React.createElement' provides at most '2'.
+!!! related TS2728 tests/cases/compiler/jsxIssuesErrorWhenTagExpectsTooManyArguments.tsx:12:10: 'MyComp3' is declared here.
+    const c  = <MyComp2 x={2}/>; // Should be OK, `context` is allowed, per react rules
+    
+    declare function MyTagWithOptionalNonJSXBits(props: MyProps, context: any, nonReactArg?: string): JSX.Element;
+    const d = <MyTagWithOptionalNonJSXBits x={2} />; // Technically OK, but probably questionable

tests/baselines/reference/jsxIssuesErrorWhenTagExpectsTooManyArguments.js

@@ -0,0 +1,44 @@
+//// [jsxIssuesErrorWhenTagExpectsTooManyArguments.tsx]
+/// <reference path="/.lib/react16.d.ts" />
+
+import * as React from "react";
+
+interface MyProps {
+    x: number;
+}
+
+function MyComp4(props: MyProps, context: any, bad: any, verybad: any) {
+    return <div></div>;
+}
+function MyComp3(props: MyProps, context: any, bad: any) {
+    return <div></div>;
+}
+function MyComp2(props: MyProps, context: any) {
+    return <div></div>
+}
+
+const a = <MyComp4 x={2}/>; // using `MyComp` as a component should error - it expects more arguments than react provides
+const b = <MyComp3 x={2}/>; // using `MyComp` as a component should error - it expects more arguments than react provides
+const c  = <MyComp2 x={2}/>; // Should be OK, `context` is allowed, per react rules
+
+declare function MyTagWithOptionalNonJSXBits(props: MyProps, context: any, nonReactArg?: string): JSX.Element;
+const d = <MyTagWithOptionalNonJSXBits x={2} />; // Technically OK, but probably questionable
+
+//// [jsxIssuesErrorWhenTagExpectsTooManyArguments.js]
+"use strict";
+/// <reference path="react16.d.ts" />
+exports.__esModule = true;
+var React = require("react");
+function MyComp4(props, context, bad, verybad) {
+    return React.createElement("div", null);
+}
+function MyComp3(props, context, bad) {
+    return React.createElement("div", null);
+}
+function MyComp2(props, context) {
+    return React.createElement("div", null);
+}
+var a = React.createElement(MyComp4, { x: 2 }); // using `MyComp` as a component should error - it expects more arguments than react provides
+var b = React.createElement(MyComp3, { x: 2 }); // using `MyComp` as a component should error - it expects more arguments than react provides
+var c = React.createElement(MyComp2, { x: 2 }); // Should be OK, `context` is allowed, per react rules
+var d = React.createElement(MyTagWithOptionalNonJSXBits, { x: 2 }); // Technically OK, but probably questionable