[flang][OpenMP] Skip implicit typing for OpenMPDeclarativeConstruct

flang/lib/Semantics/resolve-names.cpp

@@ -1661,9 +1661,14 @@ class OmpVisitor : public virtual DeclarationVisitor {
   }
   bool Pre(const parser::OpenMPDeclarativeConstruct &x) {
     AddOmpSourceRange(x.source);
+    // Without skipping implicit typing, declarative constructs
+    // can implicitly declare variables instead of only using the
+    // ones already declared in the Fortran sources.
+    SkipImplicitTyping(true);
     return true;
   }
   void Post(const parser::OpenMPDeclarativeConstruct &) {
+    SkipImplicitTyping(false);
     messageHandler().set_currStmtSource(std::nullopt);
   }
   bool Pre(const parser::OpenMPDepobjConstruct &x) {

flang/test/Semantics/OpenMP/declare-simd-linear.f90

@@ -0,0 +1,12 @@
+! RUN: %python %S/../test_errors.py %s %flang -fopenmp
+! Test declare simd with linear clause does not cause an implicit declaration of i
+
+module mod
+contains
+subroutine test(i)
+!$omp declare simd linear(i:1)
+  implicit none
+  integer*8 i
+  i=i+2
+end subroutine
+end module

flang/test/Semantics/OpenMP/linear-clause01.f90

@@ -24,12 +24,10 @@ subroutine linear_clause_02(arg_01, arg_02)
     !$omp declare simd linear(uval(arg_02))
     integer, value, intent(in) :: arg_02
 
-    !ERROR: The list item 'var' specified without the REF 'linear-modifier' must be of INTEGER type
     !ERROR: If the `linear-modifier` is REF or UVAL, the list item 'var' must be a dummy argument without the VALUE attribute
     !ERROR: The list item `var` must be a dummy argument
     !ERROR: The list item `var` in a LINEAR clause must not be Cray Pointer or a variable with POINTER attribute
     !$omp declare simd linear(uval(var))
-    !ERROR: The type of 'var' has already been implicitly declared
     integer, pointer :: var
 end subroutine linear_clause_02