From 7cd94d212361bc5662e8cc6959cd32edca1df03a Mon Sep 17 00:00:00 2001
From: Andrew Kelley <andrew@ziglang.org>
Date: Sat, 15 May 2021 21:20:06 -0700
Subject: [PATCH] stage2: omit Decl compile errors from failed AstGen files

Just like when new parse errors occur during an update, when new AstGen
errors occur during an update, we do not reveal compile errors for Decl
objects which are inside of a newly failed File. Once the File passes
AstGen successfully, it will be compared with the previously succeeded
ZIR and the saved Decl compile errors will be handled properly.
---
 src/Compilation.zig  | 28 ++++++++++++----------------
 src/Module.zig       |  7 +++++++
 test/stage2/test.zig |  7 +++----
 3 files changed, 22 insertions(+), 20 deletions(-)

diff --git a/src/Compilation.zig b/src/Compilation.zig
index ac26b89926..6e6fab5cc2 100644
--- a/src/Compilation.zig
+++ b/src/Compilation.zig
@@ -1696,17 +1696,15 @@ pub fn totalErrorCount(self: *Compilation) usize {
         // the previous parse success, including compile errors, but we cannot
         // emit them until the file succeeds parsing.
         for (module.failed_decls.items()) |entry| {
-            if (entry.key.namespace.file_scope.status == .parse_failure) {
-                continue;
+            if (entry.key.namespace.file_scope.okToReportErrors()) {
+                total += 1;
             }
-            total += 1;
         }
         if (module.emit_h) |emit_h| {
             for (emit_h.failed_decls.items()) |entry| {
-                if (entry.key.namespace.file_scope.status == .parse_failure) {
-                    continue;
+                if (entry.key.namespace.file_scope.okToReportErrors()) {
+                    total += 1;
                 }
-                total += 1;
             }
         }
     }
@@ -1767,21 +1765,19 @@ pub fn getAllErrorsAlloc(self: *Compilation) !AllErrors {
             }
         }
         for (module.failed_decls.items()) |entry| {
-            if (entry.key.namespace.file_scope.status == .parse_failure) {
-                // Skip errors for Decls within files that had a parse failure.
-                // We'll try again once parsing succeeds.
-                continue;
+            // Skip errors for Decls within files that had a parse failure.
+            // We'll try again once parsing succeeds.
+            if (entry.key.namespace.file_scope.okToReportErrors()) {
+                try AllErrors.add(module, &arena, &errors, entry.value.*);
             }
-            try AllErrors.add(module, &arena, &errors, entry.value.*);
         }
         if (module.emit_h) |emit_h| {
             for (emit_h.failed_decls.items()) |entry| {
-                if (entry.key.namespace.file_scope.status == .parse_failure) {
-                    // Skip errors for Decls within files that had a parse failure.
-                    // We'll try again once parsing succeeds.
-                    continue;
+                // Skip errors for Decls within files that had a parse failure.
+                // We'll try again once parsing succeeds.
+                if (entry.key.namespace.file_scope.okToReportErrors()) {
+                    try AllErrors.add(module, &arena, &errors, entry.value.*);
                 }
-                try AllErrors.add(module, &arena, &errors, entry.value.*);
             }
         }
         for (module.failed_exports.items()) |entry| {
diff --git a/src/Module.zig b/src/Module.zig
index f31b243819..2227e47d72 100644
--- a/src/Module.zig
+++ b/src/Module.zig
@@ -1138,6 +1138,13 @@ pub const Scope = struct {
             const loc = std.zig.findLineColumn(file.source.bytes, src);
             std.debug.print("{s}:{d}:{d}\n", .{ file.sub_file_path, loc.line + 1, loc.column + 1 });
         }
+
+        pub fn okToReportErrors(file: File) bool {
+            return switch (file.status) {
+                .parse_failure, .astgen_failure => false,
+                else => true,
+            };
+        }
     };
 
     /// This is the context needed to semantically analyze ZIR instructions and
diff --git a/test/stage2/test.zig b/test/stage2/test.zig
index 56fe2b026f..dfe3e7cbdf 100644
--- a/test/stage2/test.zig
+++ b/test/stage2/test.zig
@@ -1225,7 +1225,7 @@ pub fn addCases(ctx: *TestContext) !void {
     {
         var case = ctx.obj("variable shadowing", linux_x64);
         case.addError(
-            \\pub export fn _start() noreturn {
+            \\export fn _start() noreturn {
             \\    var i: u32 = 10;
             \\    var i: u32 = 10;
             \\    unreachable;
@@ -1251,7 +1251,7 @@ pub fn addCases(ctx: *TestContext) !void {
         var case = ctx.obj("@compileLog", linux_x64);
         // The other compile error prevents emission of a "found compile log" statement.
         case.addError(
-            \\pub export fn _start() noreturn {
+            \\export fn _start() noreturn {
             \\    const b = true;
             \\    var f: u32 = 1;
             \\    @compileLog(b, 20, f, x);
@@ -1293,10 +1293,9 @@ pub fn addCases(ctx: *TestContext) !void {
             \\    _ = foo;
             \\}
             \\extern var foo: i32;
-            \\pub export fn _start() void {}
         , &[_][]const u8{":2:9: error: unable to resolve comptime value"});
         case.addError(
-            \\pub export fn _start() void {
+            \\export fn entry() void {
             \\    _ = foo;
             \\}
             \\extern var foo;