Fix lack of error on default export of nonexistant name (microsoft#40094)

* Modify test harness so it can report underlying issue, fix small parent pointer issue

* Fix underlying export asignment check issue and fix lints

* Ensure class/function duplicate declaration errors are reported regarless of which is encountered first

* Ensure flag conflict errors are reported regardless of which declaration is encountered first

Author: weswigham

Diff for: src/compiler/checker.ts

@@ -32269,11 +32269,8 @@ namespace ts {
                 }
 
                 if (symbol.parent) {
-                    // run check once for the first declaration
-                    if (getDeclarationOfKind(symbol, node.kind) === node) {
-                        // run check on export symbol to check that modifiers agree across all exported declarations
-                        checkFunctionOrConstructorSymbol(symbol);
-                    }
+                    // run check on export symbol to check that modifiers agree across all exported declarations
+                    checkFunctionOrConstructorSymbol(symbol);
                 }
             }
 
@@ -34457,6 +34454,7 @@ namespace ts {
             const typeWithThis = getTypeWithThisArgument(type);
             const staticType = <ObjectType>getTypeOfSymbol(symbol);
             checkTypeParameterListsIdentical(symbol);
+            checkFunctionOrConstructorSymbol(symbol);
             checkClassForDuplicateDeclarations(node);
 
             // Only check for reserved static identifiers on non-ambient context.
@@ -35645,6 +35643,9 @@ namespace ts {
                         checkExpressionCached(node.expression);
                     }
                 }
+                else {
+                    checkExpressionCached(node.expression); // doesn't resolve, check as expression to mark as error
+                }
 
                 if (getEmitDeclarations(compilerOptions)) {
                     collectLinkedAliases(node.expression as Identifier, /*setVisibility*/ true);

Diff for: src/compiler/program.ts

@@ -1854,7 +1854,7 @@ namespace ts {
                     switch (node.kind) {
                         case SyntaxKind.ImportClause:
                             if ((node as ImportClause).isTypeOnly) {
-                                diagnostics.push(createDiagnosticForNode(node.parent, Diagnostics._0_declarations_can_only_be_used_in_TypeScript_files, "import type"));
+                                diagnostics.push(createDiagnosticForNode(parent, Diagnostics._0_declarations_can_only_be_used_in_TypeScript_files, "import type"));
                                 return "skip";
                             }
                             break;

Diff for: src/harness/compilerImpl.ts

@@ -256,9 +256,29 @@ namespace compiler {
         if (compilerOptions.skipDefaultLibCheck === undefined) compilerOptions.skipDefaultLibCheck = true;
         if (compilerOptions.noErrorTruncation === undefined) compilerOptions.noErrorTruncation = true;
 
+        const preProgram = ts.createProgram(rootFiles || [], { ...compilerOptions, traceResolution: false }, host);
+        const preErrors = ts.getPreEmitDiagnostics(preProgram);
+
         const program = ts.createProgram(rootFiles || [], compilerOptions, host);
         const emitResult = program.emit();
-        const errors = ts.getPreEmitDiagnostics(program);
+        const postErrors = ts.getPreEmitDiagnostics(program);
+        const errors = (preErrors.length !== postErrors.length) ? [...postErrors,
+            ts.addRelatedInfo(
+                ts.createCompilerDiagnostic({
+                    category: ts.DiagnosticCategory.Error,
+                    code: -1,
+                    key: "-1",
+                    message: `Pre-emit (${preErrors.length}) and post-emit (${postErrors.length}) diagnostic counts do not match! This can indicate that a semantic _error_ was added by the emit resolver - such an error may not be reflected on the command line or in the editor, but may be captured in a baseline here!`
+                }),
+                ts.createCompilerDiagnostic({
+                    category: ts.DiagnosticCategory.Error,
+                    code: -1,
+                    key: "-1",
+                    message: `The excess diagnostics are:`
+                }),
+                ...ts.filter(postErrors, p => !ts.some(preErrors, p2 => ts.compareDiagnostics(p, p2) === ts.Comparison.EqualTo))
+            )
+        ] : postErrors;
         return new CompilationResult(host, compilerOptions, program, emitResult, errors);
     }
 }

Diff for: tests/baselines/reference/exportDefaultMissingName.errors.txt

@@ -0,0 +1,7 @@
+tests/cases/compiler/exportDefaultMissingName.ts(1,16): error TS2304: Cannot find name 'xyzzy'.
+
+
+==== tests/cases/compiler/exportDefaultMissingName.ts (1 errors) ====
+    export default xyzzy;
+                   ~~~~~
+!!! error TS2304: Cannot find name 'xyzzy'.

Diff for: tests/baselines/reference/exportDefaultMissingName.js

@@ -0,0 +1,7 @@
+//// [exportDefaultMissingName.ts]
+export default xyzzy;
+
+//// [exportDefaultMissingName.js]
+"use strict";
+exports.__esModule = true;
+exports["default"] = xyzzy;

Diff for: tests/baselines/reference/exportDefaultMissingName.symbols

@@ -0,0 +1,3 @@
+=== tests/cases/compiler/exportDefaultMissingName.ts ===
+export default xyzzy;
+No type information for this code.

Diff for: tests/baselines/reference/exportDefaultMissingName.types

@@ -0,0 +1,4 @@
+=== tests/cases/compiler/exportDefaultMissingName.ts ===
+export default xyzzy;
+>xyzzy : any
+

Diff for: tests/cases/compiler/exportDefaultMissingName.ts

@@ -0,0 +1 @@
+export default xyzzy;