Zcu: store `LazySrcLoc` in error messages

This change modifies `Zcu.ErrorMsg` to store a `Zcu.LazySrcLoc` rather
than a `Zcu.SrcLoc`. Everything else is dominoes.

The reason for this change is incremental compilation. If a failed
`AnalUnit` is up-to-date on an update, we want to re-use the old error
messages. However, the file containing the error location may have been
modified, and `SrcLoc` cannot survive such a modification. `LazySrcLoc`
is designed to be correct across incremental updates. Therefore, we
defer source location resolution until `Compilation` gathers the compile
errors into the `ErrorBundle`.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/codegen/spirv.zig b/src/codegen/spirv.zig
index 54b7b381cf..494ec0737e 100644
--- a/src/codegen/spirv.zig
+++ b/src/codegen/spirv.zig
@@ -415,7 +415,7 @@ const DeclGen = struct {
     pub fn fail(self: *DeclGen, comptime format: []const u8, args: anytype) Error {
         @setCold(true);
         const mod = self.module;
-        const src_loc = self.module.declPtr(self.decl_index).navSrcLoc(mod).upgrade(mod);
+        const src_loc = self.module.declPtr(self.decl_index).navSrcLoc(mod);
         assert(self.error_msg == null);
         self.error_msg = try Module.ErrorMsg.create(self.module.gpa, src_loc, format, args);
         return error.CodegenFail;
@@ -6439,7 +6439,7 @@ const DeclGen = struct {
                 // TODO: Translate proper error locations.
                 assert(as.errors.items.len != 0);
                 assert(self.error_msg == null);
-                const src_loc = self.module.declPtr(self.decl_index).navSrcLoc(mod).upgrade(mod);
+                const src_loc = self.module.declPtr(self.decl_index).navSrcLoc(mod);
                 self.error_msg = try Module.ErrorMsg.create(self.module.gpa, src_loc, "failed to assemble SPIR-V inline assembly", .{});
                 const notes = try self.module.gpa.alloc(Module.ErrorMsg, as.errors.items.len);