[clang] [clang] Diagnose config_macros before building modules (PR #83641)

[Volodymyr Sapsai via cfe-commits]

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@@ -22,7 +58,10 @@
 #define WANT_BAR 1 // expected-note{{macro was defined here}}
 @import config; // expected-warning{{definition of configuration macro 'WANT_BAR' has no effect on the import of 'config'; pass '-DWANT_BAR=...' on the command line to configure the module}}
 
-// RUN: rm -rf %t
-// RUN: %clang_cc1 -std=c99 -fmodules -fimplicit-module-maps -x objective-c -fmodules-cache-path=%t -DWANT_FOO=1 -emit-module -fmodule-name=config %S/Inputs/module.modulemap
-// RUN: %clang_cc1 -std=c99 -fmodules -fimplicit-module-maps -fmodules-cache-path=%t -I %S/Inputs -DWANT_FOO=1 %s -verify
+//--- config_error.m
 
+#ifdef TEST_ERROR
+#define SOME_VALUE 5 // expected-note{{macro was defined here}}
+ at import config_error; // expected-error{{could not build module}} \
+                      // expected-warning{{definition of configuration macro 'SOME_VALUE' has no effect on the import of 'config_error';}}
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vsapsai wrote:

Not sure if it is worth testing the part `pass '-DSOME_VALUE=...' on the command line to configure the module` but can confirm there is an actionable recommendation here.

https://github.com/llvm/llvm-project/pull/83641